Show queued jobs before finished jobs

The few queued builds practically vanish at the bottom of the page otherwise.
Merge pull request #1426 from NixOS/queue-runner-wants-after
2025-01-23 21:11:47 +01:00 · 2024-12-05 19:28:15 -05:00 · 2024-12-03 01:44:55 +01:00 · 2024-11-26 08:53:13 +01:00 · 2024-11-26 08:52:24 +01:00 · 2024-11-25 10:13:36 -05:00
105 changed files with 1256 additions and 1486 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -1,48 +1,8 @@
-/.pls_cache
-*.o
 *~
-Makefile
-Makefile.in
-.deps
-.hydra-data
-/config.guess
-/config.log
-/config.status
-/config.sub
-/configure
-/depcomp
-/libtool
-/ltmain.sh
-/autom4te.cache
-/aclocal.m4
-/missing
-/install-sh
+.test_info.*
 /src/sql/hydra-postgresql.sql
 /src/sql/hydra-sqlite.sql
 /src/sql/tmp.sqlite
-/src/hydra-eval-jobs/hydra-eval-jobs
-/src/root/static/bootstrap
-/src/root/static/js/flot
-/tests
-/doc/manual/images
-/doc/manual/manual.html
-/doc/manual/manual.pdf
-/t/.bzr*
-/t/.git*
-/t/.hg*
-/t/nix
-/t/data
-/t/jobs/config.nix
-t/jobs/declarative/project.json
-/inst
-hydra-config.h
-hydra-config.h.in
 result
 result-*
 outputs
-config
-stamp-h1
-src/hydra-evaluator/hydra-evaluator
-src/hydra-queue-runner/hydra-queue-runner
-src/root/static/fontawesome/
-src/root/static/bootstrap*/
--- a/.yath.rc
+++ b/.yath.rc
@@ -1,2 +0,0 @@
-[test]
-I=rel(t/lib)
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,12 +0,0 @@
-SUBDIRS = src doc
-if CAN_DO_CHECK
-  SUBDIRS += t
-endif
-
-BOOTCLEAN_SUBDIRS = $(SUBDIRS)
-DIST_SUBDIRS      = $(SUBDIRS)
-EXTRA_DIST        = nixos-modules/hydra.nix
-
-install-data-local: nixos-modules/hydra.nix
-	$(INSTALL) -d $(DESTDIR)$(datadir)/nix
-	$(INSTALL_DATA) nixos-modules/hydra.nix $(DESTDIR)$(datadir)/nix/hydra-module.nix
--- a/README.md
+++ b/README.md
@@ -39,16 +39,16 @@ In order to evaluate and build anything you need to create _projects_ that conta
 #### Creating A Project
 Log in as administrator, click "_Admin_" and select "_Create project_". Fill the form as follows:

- **Identifier**: `hello`
+- **Identifier**: `hello-project`
 - **Display name**: `hello`
 - **Description**: `hello project`

 Click "_Create project_".

 #### Creating A Jobset
-After creating a project you are forwarded to the project page. Click "_Actions_" and choose "_Create jobset_". Fill the form with the following values:
+After creating a project you are forwarded to the project page. Click "_Actions_" and choose "_Create jobset_". Change **Type** to Legacy for the example below. Fill the form with the following values:

- **Identifier**: `hello`
+- **Identifier**: `hello-project`
 - **Nix expression**: `examples/hello.nix` in `hydra`
 - **Check interval**: 60
 - **Scheduling shares**: 1
@@ -57,7 +57,7 @@ We have to add two inputs for this jobset. One for _nixpkgs_ and one for _hydra_

 - **Input name**: `nixpkgs`
 - **Type**: `Git checkout`
- **Value**: `https://github.com/nixos/nixpkgs-channels nixos-20.03`
+- **Value**: `https://github.com/NixOS/nixpkgs nixos-24.05`

 - **Input name**: `hydra`
 - **Type**: `Git checkout`
@@ -140,7 +140,7 @@ You can also interface with Hydra through a JSON API. The API is defined in [hyd
 ## Additional Resources

 - [Hydra User's Guide](https://nixos.org/hydra/manual/)
- [Hydra on the NixOS Wiki](https://nixos.wiki/wiki/Hydra)
+- [Hydra on the NixOS Wiki](https://wiki.nixos.org/wiki/Hydra)
 - [hydra-cli](https://github.com/nlewo/hydra-cli)
 - [Peter Simons - Hydra: Setting up your own build farm (NixOS)](https://www.youtube.com/watch?v=RXV0Y5Bn-QQ)

--- a/configure.ac
+++ b/configure.ac
@@ -1,91 +0,0 @@
-AC_INIT([Hydra], [m4_esyscmd([echo -n $(cat ./version.txt)$VERSION_SUFFIX])])
-AC_CONFIG_AUX_DIR(config)
-AM_INIT_AUTOMAKE([foreign serial-tests])
-
-AC_LANG([C++])
-
-AC_PROG_CC
-AC_PROG_INSTALL
-AC_PROG_LN_S
-AC_PROG_LIBTOOL
-AC_PROG_CXX
-
-AC_PATH_PROG([XSLTPROC], [xsltproc])
-
-AC_ARG_WITH([docbook-xsl],
-  [AS_HELP_STRING([--with-docbook-xsl=PATH],
-    [path of the DocBook XSL stylesheets])],
-  [docbookxsl="$withval"],
-  [docbookxsl="/docbook-xsl-missing"])
-AC_SUBST([docbookxsl])
-
-
-AC_DEFUN([NEED_PROG],
-[
-AC_PATH_PROG($1, $2)
-if test -z "$$1"; then
-    AC_MSG_ERROR([$2 is required])
-fi
-])
-
-NEED_PROG(perl, perl)
-
-NEED_PROG([NIX_STORE_PROGRAM], [nix-store])
-
-AC_MSG_CHECKING([whether $NIX_STORE_PROGRAM is recent enough])
-if test -n "$NIX_STORE" -a -n "$TMPDIR"
-then
-    # This may be executed from within a build chroot, so pacify
-    # `nix-store' instead of letting it choke while trying to mkdir
-    # /nix/var.
-    NIX_STATE_DIR="$TMPDIR"
-    export NIX_STATE_DIR
-fi
-if NIX_REMOTE=daemon PAGER=cat "$NIX_STORE_PROGRAM" --timeout 123 -q; then
-    AC_MSG_RESULT([yes])
-else
-    AC_MSG_RESULT([no])
-    AC_MSG_ERROR([`$NIX_STORE_PROGRAM' doesn't support `--timeout'; please use a newer version.])
-fi
-
-PKG_CHECK_MODULES([NIX], [nix-main nix-expr nix-store])
-
-testPath="$(dirname $(type -p expr))"
-AC_SUBST(testPath)
-
-CXXFLAGS+=" -include nix/config.h"
-
-AC_CONFIG_FILES([
-  Makefile
-  doc/Makefile
-  doc/manual/Makefile
-  src/Makefile
-  src/hydra-evaluator/Makefile
-  src/hydra-eval-jobs/Makefile
-  src/hydra-queue-runner/Makefile
-  src/sql/Makefile
-  src/ttf/Makefile
-  src/lib/Makefile
-  src/root/Makefile
-  src/script/Makefile
-])
-
-# Tests might be filtered out
-AM_CONDITIONAL([CAN_DO_CHECK], [test -f "$srcdir/t/api-test.t"])
-AM_COND_IF(
-  [CAN_DO_CHECK],
-  [
-    jobsPath="$(realpath ./t/jobs)"
-    AC_SUBST(jobsPath)
-    AC_CONFIG_FILES([
-      t/Makefile
-      t/jobs/config.nix
-      t/jobs/declarative/project.json
-    ])
-  ])
-
-AC_CONFIG_COMMANDS([executable-scripts], [])
-
-AC_CONFIG_HEADER([hydra-config.h])
-
-AC_OUTPUT
--- a/default.nix
+++ b/default.nix
@@ -1,6 +1,6 @@
 # The `default.nix` in flake-compat reads `flake.nix` and `flake.lock` from `src` and
 # returns an attribute set of the shape `{ defaultNix, shellNix }`

-(import (fetchTarball https://github.com/edolstra/flake-compat/archive/master.tar.gz) {
+(import (fetchTarball "https://github.com/edolstra/flake-compat/archive/master.tar.gz") {
  src = ./.;
 }).defaultNix
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,4 +0,0 @@
-SUBDIRS = manual
-BOOTCLEAN_SUBDIRS = $(SUBDIRS)
-DIST_SUBDIRS      = $(SUBDIRS)
-
--- a/doc/manual/Makefile.am
+++ b/doc/manual/Makefile.am
@@ -1,6 +0,0 @@
-MD_FILES = src/*.md
-
-EXTRA_DIST = $(MD_FILES)
-
-install: $(MD_FILES)
-	mdbook build . -d $(docdir)
--- a/doc/manual/meson.build
+++ b/doc/manual/meson.build
@@ -0,0 +1,36 @@
+srcs = files(
+  'src/SUMMARY.md',
+  'src/about.md',
+  'src/api.md',
+  'src/configuration.md',
+  'src/hacking.md',
+  'src/installation.md',
+  'src/introduction.md',
+  'src/jobs.md',
+  'src/monitoring/README.md',
+  'src/notifications.md',
+  'src/plugins/README.md',
+  'src/plugins/RunCommand.md',
+  'src/plugins/declarative-projects.md',
+  'src/projects.md',
+  'src/webhooks.md',
+)
+
+manual = custom_target(
+  'manual',
+  command: [
+    mdbook,
+    'build',
+    '@SOURCE_ROOT@/doc/manual',
+    '-d', meson.current_build_dir() / 'html'
+  ],
+  depend_files: srcs,
+  output: ['html'],
+  build_by_default: true,
+)
+
+install_subdir(
+  manual.full_path(),
+  install_dir: get_option('datadir') / 'doc/hydra',
+  strip_directory: true,
+)
--- a/doc/manual/src/hacking.md
+++ b/doc/manual/src/hacking.md
@@ -15,12 +15,18 @@ and dependencies can be found:
 $ nix-shell
 ```

+of when flakes are enabled:
+
+```console
+$ nix develop
+```
+
 To build Hydra, you should then do:

 ```console
 [nix-shell]$ autoreconfPhase
 [nix-shell]$ configurePhase
-[nix-shell]$ make
+[nix-shell]$ make -j$(nproc)
 ```

 You start a local database, the webserver, and other components with
@@ -30,6 +36,8 @@ foreman:
 $ foreman start
 ```

+The Hydra interface will be available on port 63333, with an admin user named "alice" with password "foobar"
+
 You can run just the Hydra web server in your source tree as follows:

 ```console
--- a/doc/manual/src/plugins/README.md
+++ b/doc/manual/src/plugins/README.md
@@ -42,7 +42,7 @@ Sets CircleCI status.

 ## Compress build logs

-Compresses build logs after a build with bzip2.
+Compresses build logs after a build with bzip2 or zstd.

 ### Configuration options

@@ -50,6 +50,14 @@ Compresses build logs after a build with bzip2.

 Enable log compression

+- `compress_build_logs_compression`
+
+Which compression format to use. Valid values are bzip2 (default) and zstd.
+
+- `compress_build_logs_silent`
+
+Whether to compress logs silently.
+
 ### Example

 ```xml
--- a/doc/manual/src/webhooks.md
+++ b/doc/manual/src/webhooks.md
@@ -1,9 +1,12 @@
 # Webhooks

-Hydra can be notified by github's webhook to trigger a new evaluation when a
+Hydra can be notified by github or gitea with webhooks to trigger a new evaluation when a
 jobset has a github repo in its input.
-To set up a github webhook go to `https://github.com/<yourhandle>/<yourrepo>/settings` and in the `Webhooks` tab
-click on `Add webhook`.
+
+## GitHub
+
+To set up a webhook for a GitHub repository go to `https://github.com/<yourhandle>/<yourrepo>/settings`
+and in the `Webhooks` tab click on `Add webhook`.

 - In `Payload URL` fill in `https://<your-hydra-domain>/api/push-github`.
 - In `Content type` switch to `application/json`.
@@ -11,3 +14,14 @@ click on `Add webhook`.
 - For `Which events would you like to trigger this webhook?` keep the default option for events on `Just the push event.`.

 Then add the hook with `Add webhook`.
+
+## Gitea
+
+To set up a webhook for a Gitea repository go to the settings of the repository in your Gitea instance
+and in the `Webhooks` tab click on `Add Webhook` and choose `Gitea` in the drop down.
+
+- In `Target URL` fill in `https://<your-hydra-domain>/api/push-gitea`.
+- Keep HTTP method `POST`, POST Content Type `application/json` and Trigger On `Push Events`.
+- Change the branch filter to match the git branch hydra builds.
+
+Then add the hook with `Add webhook`.
--- a/examples/hello.nix
+++ b/examples/hello.nix
@@ -1,5 +1,5 @@
 #
-# jobset example file. This file canbe referenced as Nix expression
+# jobset example file. This file can be referenced as Nix expression
 # in a jobset configuration along with inputs for nixpkgs and the
 # repository containing this file.
 #
--- a/flake.lock
+++ b/flake.lock
@@ -1,114 +1,72 @@
 {
  "nodes": {
-    "flake-compat": {
+    "libgit2": {
      "flake": false,
      "locked": {
-        "lastModified": 1673956053,
-        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
-        "owner": "edolstra",
-        "repo": "flake-compat",
-        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
+        "lastModified": 1715853528,
+        "narHash": "sha256-J2rCxTecyLbbDdsyBWn9w7r3pbKRMkI9E7RvRgAqBdY=",
+        "owner": "libgit2",
+        "repo": "libgit2",
+        "rev": "36f7e21ad757a3dacc58cf7944329da6bc1d6e96",
        "type": "github"
      },
      "original": {
-        "owner": "edolstra",
-        "repo": "flake-compat",
-        "type": "github"
-      }
-    },
-    "lowdown-src": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1633514407,
-        "narHash": "sha256-Dw32tiMjdK9t3ETl5fzGrutQTzh2rufgZV4A/BbxuD4=",
-        "owner": "kristapsdz",
-        "repo": "lowdown",
-        "rev": "d2c2b44ff6c27b936ec27358a2653caaef8f73b8",
-        "type": "github"
-      },
-      "original": {
-        "owner": "kristapsdz",
-        "repo": "lowdown",
+        "owner": "libgit2",
+        "ref": "v1.8.1",
+        "repo": "libgit2",
        "type": "github"
      }
    },
    "nix": {
      "inputs": {
-        "flake-compat": "flake-compat",
-        "lowdown-src": "lowdown-src",
+        "flake-compat": [],
+        "flake-parts": [],
+        "git-hooks-nix": [],
+        "libgit2": [
+          "libgit2"
+        ],
        "nixpkgs": [
          "nixpkgs"
        ],
-        "nixpkgs-regression": "nixpkgs-regression"
+        "nixpkgs-23-11": [],
+        "nixpkgs-regression": []
      },
      "locked": {
-        "lastModified": 1706208340,
-        "narHash": "sha256-wNyHUEIiKKVs6UXrUzhP7RSJQv0A8jckgcuylzftl8k=",
+        "lastModified": 1726787955,
+        "narHash": "sha256-XFznzb8L4SdUm9u+w3DPpMWJhffuv+/6+aiVl00slns=",
        "owner": "NixOS",
        "repo": "nix",
-        "rev": "2c4bb93ba5a97e7078896ebc36385ce172960e4e",
+        "rev": "a7fdef6858dd45b9d7bda7c92324c63faee7f509",
        "type": "github"
      },
      "original": {
        "owner": "NixOS",
-        "ref": "2.19-maintenance",
+        "ref": "2.24-maintenance",
        "repo": "nix",
        "type": "github"
      }
    },
    "nixpkgs": {
      "locked": {
-        "lastModified": 1701615100,
-        "narHash": "sha256-7VI84NGBvlCTduw2aHLVB62NvCiZUlALLqBe5v684Aw=",
+        "lastModified": 1726688310,
+        "narHash": "sha256-Xc9lEtentPCEtxc/F1e6jIZsd4MPDYv4Kugl9WtXlz0=",
        "owner": "NixOS",
        "repo": "nixpkgs",
-        "rev": "e9f06adb793d1cca5384907b3b8a4071d5d7cb19",
+        "rev": "dbebdd67a6006bb145d98c8debf9140ac7e651d0",
        "type": "github"
      },
      "original": {
        "owner": "NixOS",
-        "ref": "nixos-23.05",
+        "ref": "nixos-24.05-small",
        "repo": "nixpkgs",
        "type": "github"
      }
    },
-    "nixpkgs-for-fileset": {
-      "locked": {
-        "lastModified": 1706098335,
-        "narHash": "sha256-r3dWjT8P9/Ah5m5ul4WqIWD8muj5F+/gbCdjiNVBKmU=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "a77ab169a83a4175169d78684ddd2e54486ac651",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-23.11",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs-regression": {
-      "locked": {
-        "lastModified": 1643052045,
-        "narHash": "sha256-uGJ0VXIhWKGXxkeNnq4TvV3CIOkUJ3PAoLZ3HMzNVMw=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
-        "type": "github"
-      }
-    },
    "root": {
      "inputs": {
+        "libgit2": "libgit2",
        "nix": "nix",
-        "nixpkgs": "nixpkgs",
-        "nixpkgs-for-fileset": "nixpkgs-for-fileset"
+        "nixpkgs": "nixpkgs"
      }
    }
  },
--- a/flake.nix
+++ b/flake.nix
@@ -1,79 +1,37 @@
 {
  description = "A Nix-based continuous build system";

-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
-  inputs.nix.url = "github:NixOS/nix/2.19-maintenance";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05-small";
+
+  inputs.libgit2 = { url = "github:libgit2/libgit2/v1.8.1"; flake = false; };
+  inputs.nix.url = "github:NixOS/nix/2.24-maintenance";
  inputs.nix.inputs.nixpkgs.follows = "nixpkgs";
+  inputs.nix.inputs.libgit2.follows = "libgit2";

-  # TODO get rid of this once https://github.com/NixOS/nix/pull/9546 is
-  # mered and we upgrade or Nix, so the main `nixpkgs` input is at least
-  # 23.11 and has `lib.fileset`.
-  inputs.nixpkgs-for-fileset.url = "github:NixOS/nixpkgs/nixos-23.11";
+  # hide nix dev tooling from our lock file
+  inputs.nix.inputs.flake-parts.follows = "";
+  inputs.nix.inputs.git-hooks-nix.follows = "";
+  inputs.nix.inputs.nixpkgs-regression.follows = "";
+  inputs.nix.inputs.nixpkgs-23-11.follows = "";
+  inputs.nix.inputs.flake-compat.follows = "";

-  outputs = { self, nixpkgs, nix, nixpkgs-for-fileset }:
+  outputs = { self, nixpkgs, nix, ... }:
    let
      systems = [ "x86_64-linux" "aarch64-linux" ];
      forEachSystem = nixpkgs.lib.genAttrs systems;
-
-      overlayList = [ self.overlays.default nix.overlays.default ];
-
-      pkgsBySystem = forEachSystem (system: import nixpkgs {
-        inherit system;
-        overlays = overlayList;
-      });
-
-      # NixOS configuration used for VM tests.
-      hydraServer =
-        { config, pkgs, ... }:
-        {
-          imports = [ self.nixosModules.hydraTest ];
-
-          virtualisation.memorySize = 1024;
-          virtualisation.writableStore = true;
-
-          environment.systemPackages = [ pkgs.perlPackages.LWP pkgs.perlPackages.JSON ];
-
-          nix = {
-            # Without this nix tries to fetch packages from the default
-            # cache.nixos.org which is not reachable from this sandboxed NixOS test.
-            binaryCaches = [ ];
-          };
-        };
-
    in
    rec {

      # A Nixpkgs overlay that provides a 'hydra' package.
      overlays.default = final: prev: {
-
-        # Add LDAP dependencies that aren't currently found within nixpkgs.
-        perlPackages = prev.perlPackages // {
-
-          PrometheusTiny = final.perlPackages.buildPerlPackage {
-            pname = "Prometheus-Tiny";
-            version = "0.007";
-            src = final.fetchurl {
-              url = "mirror://cpan/authors/id/R/RO/ROBN/Prometheus-Tiny-0.007.tar.gz";
-              sha256 = "0ef8b226a2025cdde4df80129dd319aa29e884e653c17dc96f4823d985c028ec";
-            };
-            buildInputs = with final.perlPackages; [ HTTPMessage Plack TestException ];
-            meta = {
-              homepage = "https://github.com/robn/Prometheus-Tiny";
-              description = "A tiny Prometheus client";
-              license = with final.lib.licenses; [ artistic1 gpl1Plus ];
-            };
-          };
-
-        };
-
        hydra = final.callPackage ./package.nix {
-          inherit (nixpkgs-for-fileset.lib) fileset;
+          inherit (nixpkgs.lib) fileset;
          rawSrc = self;
+          nix-perl-bindings = final.nixComponents.nix-perl-bindings;
        };
      };

      hydraJobs = {
-
        build = forEachSystem (system: packages.${system}.hydra);

        buildNoTests = forEachSystem (system:
@@ -82,297 +40,22 @@
          })
        );

-        manual = forEachSystem (system:
-          let pkgs = pkgsBySystem.${system}; in
-          pkgs.runCommand "hydra-manual-${pkgs.hydra.version}" { }
+        manual = forEachSystem (system: let
+          pkgs = nixpkgs.legacyPackages.${system};
+          hydra = self.packages.${pkgs.hostPlatform.system}.hydra;
+        in
+          pkgs.runCommand "hydra-manual-${hydra.version}" { }
            ''
              mkdir -p $out/share
-              cp -prvd ${pkgs.hydra}/share/doc $out/share/
+              cp -prvd ${hydra.doc}/share/doc $out/share/

              mkdir $out/nix-support
              echo "doc manual $out/share/doc/hydra" >> $out/nix-support/hydra-build-products
            '');

-        tests.install = forEachSystem (system:
-          with import (nixpkgs + "/nixos/lib/testing-python.nix") { inherit system; };
-          simpleTest {
-            name = "hydra-install";
-            nodes.machine = hydraServer;
-            testScript =
-              ''
-                machine.wait_for_job("hydra-init")
-                machine.wait_for_job("hydra-server")
-                machine.wait_for_job("hydra-evaluator")
-                machine.wait_for_job("hydra-queue-runner")
-                machine.wait_for_open_port(3000)
-                machine.succeed("curl --fail http://localhost:3000/")
-              '';
-          });
-
-        tests.notifications = forEachSystem (system:
-          let pkgs = pkgsBySystem.${system}; in
-          with import (nixpkgs + "/nixos/lib/testing-python.nix") { inherit system; };
-          simpleTest {
-            name = "hydra-notifications";
-            nodes.machine = { pkgs, ... }: {
-              imports = [ hydraServer ];
-              services.hydra-dev.extraConfig = ''
-                <influxdb>
-                  url = http://127.0.0.1:8086
-                  db = hydra
-                </influxdb>
-              '';
-              services.influxdb.enable = true;
-            };
-            testScript = ''
-              machine.wait_for_job("hydra-init")
-
-              # Create an admin account and some other state.
-              machine.succeed(
-                  """
-                      su - hydra -c "hydra-create-user root --email-address 'alice@example.org' --password foobar --role admin"
-                      mkdir /run/jobset
-                      chmod 755 /run/jobset
-                      cp ${./t/jobs/api-test.nix} /run/jobset/default.nix
-                      chmod 644 /run/jobset/default.nix
-                      chown -R hydra /run/jobset
-              """
-              )
-
-              # Wait until InfluxDB can receive web requests
-              machine.wait_for_job("influxdb")
-              machine.wait_for_open_port(8086)
-
-              # Create an InfluxDB database where hydra will write to
-              machine.succeed(
-                  "curl -XPOST 'http://127.0.0.1:8086/query' "
-                  + "--data-urlencode 'q=CREATE DATABASE hydra'"
-              )
-
-              # Wait until hydra-server can receive HTTP requests
-              machine.wait_for_job("hydra-server")
-              machine.wait_for_open_port(3000)
-
-              # Setup the project and jobset
-              machine.succeed(
-                  "su - hydra -c 'perl -I ${pkgs.hydra.perlDeps}/lib/perl5/site_perl ${./t/setup-notifications-jobset.pl}' >&2"
-              )
-
-              # Wait until hydra has build the job and
-              # the InfluxDBNotification plugin uploaded its notification to InfluxDB
-              machine.wait_until_succeeds(
-                  "curl -s -H 'Accept: application/csv' "
-                  + "-G 'http://127.0.0.1:8086/query?db=hydra' "
-                  + "--data-urlencode 'q=SELECT * FROM hydra_build_status' | grep success"
-              )
-            '';
-          });
-
-        tests.gitea = forEachSystem (system:
-          let pkgs = pkgsBySystem.${system}; in
-          with import (nixpkgs + "/nixos/lib/testing-python.nix") { inherit system; };
-          makeTest {
-            name = "hydra-gitea";
-            nodes.machine = { pkgs, ... }: {
-              imports = [ hydraServer ];
-              services.hydra-dev.extraConfig = ''
-                <gitea_authorization>
-                root=d7f16a3412e01a43a414535b16007c6931d3a9c7
-                </gitea_authorization>
-              '';
-              nix = {
-                distributedBuilds = true;
-                buildMachines = [{
-                  hostName = "localhost";
-                  systems = [ system ];
-                }];
-                binaryCaches = [ ];
-              };
-              services.gitea = {
-                enable = true;
-                database.type = "postgres";
-                disableRegistration = true;
-                httpPort = 3001;
-              };
-              services.openssh.enable = true;
-              environment.systemPackages = with pkgs; [ gitea git jq gawk ];
-              networking.firewall.allowedTCPPorts = [ 3000 ];
-            };
-            skipLint = true;
-            testScript =
-              let
-                scripts.mktoken = pkgs.writeText "token.sql" ''
-                  INSERT INTO access_token (id, uid, name, created_unix, updated_unix, token_hash, token_salt, token_last_eight) VALUES (1, 1, 'hydra', 1617107360, 1617107360, 'a930f319ca362d7b49a4040ac0af74521c3a3c3303a86f327b01994430672d33b6ec53e4ea774253208686c712495e12a486', 'XRjWE9YW0g', '31d3a9c7');
-                '';
-
-                scripts.git-setup = pkgs.writeShellScript "setup.sh" ''
-                  set -x
-                  mkdir -p /tmp/repo $HOME/.ssh
-                  cat ${snakeoilKeypair.privkey} > $HOME/.ssh/privk
-                  chmod 0400 $HOME/.ssh/privk
-                  git -C /tmp/repo init
-                  cp ${smallDrv} /tmp/repo/jobset.nix
-                  git -C /tmp/repo add .
-                  git config --global user.email test@localhost
-                  git config --global user.name test
-                  git -C /tmp/repo commit -m 'Initial import'
-                  git -C /tmp/repo remote add origin gitea@machine:root/repo
-                  GIT_SSH_COMMAND='ssh -i $HOME/.ssh/privk -o StrictHostKeyChecking=no' \
-                    git -C /tmp/repo push origin master
-                  git -C /tmp/repo log >&2
-                '';
-
-                scripts.hydra-setup = pkgs.writeShellScript "hydra.sh" ''
-                  set -x
-                  su -l hydra -c "hydra-create-user root --email-address \
-                    'alice@example.org' --password foobar --role admin"
-
-                  URL=http://localhost:3000
-                  USERNAME="root"
-                  PASSWORD="foobar"
-                  PROJECT_NAME="trivial"
-                  JOBSET_NAME="trivial"
-                  mycurl() {
-                    curl --referer $URL -H "Accept: application/json" \
-                      -H "Content-Type: application/json" $@
-                  }
-
-                  cat >data.json <<EOF
-                  { "username": "$USERNAME", "password": "$PASSWORD" }
-                  EOF
-                  mycurl -X POST -d '@data.json' $URL/login -c hydra-cookie.txt
-
-                  cat >data.json <<EOF
-                  {
-                    "displayname":"Trivial",
-                    "enabled":"1",
-                    "visible":"1"
-                  }
-                  EOF
-                  mycurl --silent -X PUT $URL/project/$PROJECT_NAME \
-                    -d @data.json -b hydra-cookie.txt
-
-                  cat >data.json <<EOF
-                  {
-                    "description": "Trivial",
-                    "checkinterval": "60",
-                    "enabled": "1",
-                    "visible": "1",
-                    "keepnr": "1",
-                    "enableemail": true,
-                    "emailoverride": "hydra@localhost",
-                    "type": 0,
-                    "nixexprinput": "git",
-                    "nixexprpath": "jobset.nix",
-                    "inputs": {
-                      "git": {"value": "http://localhost:3001/root/repo.git", "type": "git"},
-                      "gitea_repo_name": {"value": "repo", "type": "string"},
-                      "gitea_repo_owner": {"value": "root", "type": "string"},
-                      "gitea_status_repo": {"value": "git", "type": "string"},
-                      "gitea_http_url": {"value": "http://localhost:3001", "type": "string"}
-                    }
-                  }
-                  EOF
-
-                  mycurl --silent -X PUT $URL/jobset/$PROJECT_NAME/$JOBSET_NAME \
-                    -d @data.json -b hydra-cookie.txt
-                '';
-
-                api_token = "d7f16a3412e01a43a414535b16007c6931d3a9c7";
-
-                snakeoilKeypair = {
-                  privkey = pkgs.writeText "privkey.snakeoil" ''
-                    -----BEGIN EC PRIVATE KEY-----
-                    MHcCAQEEIHQf/khLvYrQ8IOika5yqtWvI0oquHlpRLTZiJy5dRJmoAoGCCqGSM49
-                    AwEHoUQDQgAEKF0DYGbBwbj06tA3fd/+yP44cvmwmHBWXZCKbS+RQlAKvLXMWkpN
-                    r1lwMyJZoSGgBHoUahoYjTh9/sJL7XLJtA==
-                    -----END EC PRIVATE KEY-----
-                  '';
-
-                  pubkey = pkgs.lib.concatStrings [
-                    "ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHA"
-                    "yNTYAAABBBChdA2BmwcG49OrQN33f/sj+OHL5sJhwVl2Qim0vkUJQCry1zFpKTa"
-                    "9ZcDMiWaEhoAR6FGoaGI04ff7CS+1yybQ= sakeoil"
-                  ];
-                };
-
-                smallDrv = pkgs.writeText "jobset.nix" ''
-                  { trivial = builtins.derivation {
-                      name = "trivial";
-                      system = "${system}";
-                      builder = "/bin/sh";
-                      allowSubstitutes = false;
-                      preferLocalBuild = true;
-                      args = ["-c" "echo success > $out; exit 0"];
-                    };
-                   }
-                '';
-              in
-              ''
-                import json
-
-                machine.start()
-                machine.wait_for_unit("multi-user.target")
-                machine.wait_for_open_port(3000)
-                machine.wait_for_open_port(3001)
-
-                machine.succeed(
-                    "su -l gitea -c 'GITEA_WORK_DIR=/var/lib/gitea gitea admin user create "
-                    + "--username root --password root --email test@localhost'"
-                )
-                machine.succeed("su -l postgres -c 'psql gitea < ${scripts.mktoken}'")
-
-                machine.succeed(
-                    "curl --fail -X POST http://localhost:3001/api/v1/user/repos "
-                    + "-H 'Accept: application/json' -H 'Content-Type: application/json' "
-                    + f"-H 'Authorization: token ${api_token}'"
-                    + ' -d \'{"auto_init":false, "description":"string", "license":"mit", "name":"repo", "private":false}\'''
-                )
-
-                machine.succeed(
-                    "curl --fail -X POST http://localhost:3001/api/v1/user/keys "
-                    + "-H 'Accept: application/json' -H 'Content-Type: application/json' "
-                    + f"-H 'Authorization: token ${api_token}'"
-                    + ' -d \'{"key":"${snakeoilKeypair.pubkey}","read_only":true,"title":"SSH"}\'''
-                )
-
-                machine.succeed(
-                    "${scripts.git-setup}"
-                )
-
-                machine.succeed(
-                    "${scripts.hydra-setup}"
-                )
-
-                machine.wait_until_succeeds(
-                    'curl -Lf -s http://localhost:3000/build/1 -H "Accept: application/json" '
-                    + '|  jq .buildstatus | xargs test 0 -eq'
-                )
-
-                data = machine.succeed(
-                    'curl -Lf -s "http://localhost:3001/api/v1/repos/root/repo/statuses/$(cd /tmp/repo && git show | head -n1 | awk "{print \\$2}")" '
-                    + "-H 'Accept: application/json' -H 'Content-Type: application/json' "
-                    + f"-H 'Authorization: token ${api_token}'"
-                )
-
-                response = json.loads(data)
-
-                assert len(response) == 2, "Expected exactly two status updates for latest commit!"
-                assert response[0]['status'] == "success", "Expected latest status to be success!"
-                assert response[1]['status'] == "pending", "Expected first status to be pending!"
-
-                machine.shutdown()
-              '';
-          });
-
-        tests.validate-openapi = forEachSystem (system:
-          let pkgs = pkgsBySystem.${system}; in
-          pkgs.runCommand "validate-openapi"
-          { buildInputs = [ pkgs.openapi-generator-cli ]; }
-          ''
-            openapi-generator-cli validate -i ${./hydra-api.yaml}
-            touch $out
-          '');
+        tests = import ./nixos-tests.nix {
+          inherit forEachSystem nixpkgs nixosModules;
+        };

        container = nixosConfigurations.container.config.system.build.toplevel;
      };
@@ -384,18 +67,24 @@
      });

      packages = forEachSystem (system: {
-        hydra = pkgsBySystem.${system}.hydra;
-        default = pkgsBySystem.${system}.hydra;
+        hydra = nixpkgs.legacyPackages.${system}.callPackage ./package.nix {
+          inherit (nixpkgs.lib) fileset;
+          rawSrc = self;
+          nix = nix.packages.${system}.nix;
+          nix-perl-bindings = nix.hydraJobs.perlBindings.${system};
+        };
+        default = self.packages.${system}.hydra;
      });

      nixosModules = import ./nixos-modules {
-        overlays = overlayList;
+        inherit self;
      };

      nixosConfigurations.container = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules =
          [
+            self.nixosModules.hydra
            self.nixosModules.hydraTest
            self.nixosModules.hydraProxy
            {
--- a/meson.build
+++ b/meson.build
@@ -0,0 +1,40 @@
+project('hydra', 'cpp',
+  version: files('version.txt'),
+  license: 'GPL-3.0',
+  default_options: [
+    'debug=true',
+    'optimization=2',
+    'cpp_std=c++20',
+  ],
+)
+
+nix_store_dep = dependency('nix-store', required: true)
+nix_main_dep = dependency('nix-main', required: true)
+nix_expr_dep = dependency('nix-expr', required: true)
+nix_flake_dep = dependency('nix-flake', required: true)
+nix_cmd_dep = dependency('nix-cmd', required: true)
+
+# Nix need extra flags not provided in its pkg-config files.
+nix_dep = declare_dependency(
+  dependencies: [
+    nix_store_dep,
+    nix_main_dep,
+    nix_expr_dep,
+    nix_flake_dep,
+    nix_cmd_dep,
+  ],
+  compile_args: ['-include', 'nix/config.h'],
+)
+
+pqxx_dep = dependency('libpqxx', required: true)
+
+prom_cpp_core_dep = dependency('prometheus-cpp-core', required: true)
+prom_cpp_pull_dep = dependency('prometheus-cpp-pull', required: true)
+
+mdbook = find_program('mdbook', native: true)
+perl = find_program('perl', native: true)
+
+subdir('doc/manual')
+subdir('nixos-modules')
+subdir('src')
+subdir('t')
--- a/nixos-modules/default.nix
+++ b/nixos-modules/default.nix
@@ -1,14 +1,13 @@
-{ overlays }:
+{ self }:

-rec {
-  hydra = {
+{
+  hydra = { pkgs, lib,... }: {
+    _file = ./default.nix;
    imports = [ ./hydra.nix ];
-    nixpkgs = { inherit overlays; };
+    services.hydra-dev.package = lib.mkDefault self.packages.${pkgs.hostPlatform.system}.hydra;
  };

  hydraTest = { pkgs, ... }: {
-    imports = [ hydra ];
-
    services.hydra-dev.enable = true;
    services.hydra-dev.hydraURL = "http://hydra.example.org";
    services.hydra-dev.notificationSender = "admin@hydra.example.org";
@@ -16,7 +15,7 @@ rec {
    systemd.services.hydra-send-stats.enable = false;

    services.postgresql.enable = true;
-    services.postgresql.package = pkgs.postgresql_11;
+    services.postgresql.package = pkgs.postgresql_12;

    # The following is to work around the following error from hydra-server:
    #   [error] Caught exception in engine "Cannot determine local time zone"
--- a/nixos-modules/hydra.nix
+++ b/nixos-modules/hydra.nix
@@ -68,8 +68,6 @@ in

      package = mkOption {
        type = types.path;
-        default = pkgs.hydra;
-        defaultText = literalExpression "pkgs.hydra";
        description = "The Hydra package.";
      };

@@ -233,7 +231,7 @@ in
      gc-keep-outputs = true;
      gc-keep-derivations = true;
    };
-    
+
    services.hydra-dev.extraConfig =
      ''
        using_frontend_proxy = 1
@@ -340,6 +338,7 @@ in
    systemd.services.hydra-queue-runner =
      { wantedBy = [ "multi-user.target" ];
        requires = [ "hydra-init.service" ];
+        wants = [ "network-online.target" ];
        after = [ "hydra-init.service" "network.target" "network-online.target" ];
        path = [ cfg.package pkgs.nettools pkgs.openssh pkgs.bzip2 config.nix.package ];
        restartTriggers = [ hydraConf ];
@@ -408,6 +407,7 @@ in
        requires = [ "hydra-init.service" ];
        after = [ "hydra-init.service" ];
        restartTriggers = [ hydraConf ];
+        path = [ pkgs.zstd ];
        environment = env // {
          PGPASSFILE = "${baseDir}/pgpass-queue-runner"; # grrr
          HYDRA_DBI = "${env.HYDRA_DBI};application_name=hydra-notify";
@@ -458,10 +458,17 @@ in
    # logs automatically after a step finishes, but this doesn't work
    # if the queue runner is stopped prematurely.
    systemd.services.hydra-compress-logs =
-      { path = [ pkgs.bzip2 ];
+      { path = [ pkgs.bzip2 pkgs.zstd ];
        script =
          ''
-            find ${baseDir}/build-logs -type f -name "*.drv" -mtime +3 -size +0c | xargs -r bzip2 -v -f
+            set -eou pipefail
+            compression=$(sed -nr 's/compress_build_logs_compression = ()/\1/p' ${baseDir}/hydra.conf)
+            if [[ $compression == "" ]]; then
+              compression="bzip2"
+            elif [[ $compression == zstd ]]; then
+              compression="zstd --rm"
+            fi
+            find ${baseDir}/build-logs -type f -name "*.drv" -mtime +3 -size +0c | xargs -r "$compression" --force --quiet
          '';
        startAt = "Sun 01:45";
      };
--- a/nixos-modules/meson.build
+++ b/nixos-modules/meson.build
@@ -0,0 +1,4 @@
+install_data('hydra.nix',
+  install_dir: get_option('datadir') / 'nix',
+  rename: ['hydra-module.nix'],
+)
--- a/nixos-tests.nix
+++ b/nixos-tests.nix
@@ -0,0 +1,307 @@
+{ forEachSystem, nixpkgs, nixosModules }:
+
+let
+  # NixOS configuration used for VM tests.
+  hydraServer =
+    { pkgs, ... }:
+    {
+      imports = [
+        nixosModules.hydra
+        nixosModules.hydraTest
+      ];
+
+      virtualisation.memorySize = 1024;
+      virtualisation.writableStore = true;
+
+      environment.systemPackages = [ pkgs.perlPackages.LWP pkgs.perlPackages.JSON ];
+
+      nix = {
+        # Without this nix tries to fetch packages from the default
+        # cache.nixos.org which is not reachable from this sandboxed NixOS test.
+        settings.substituters = [ ];
+      };
+    };
+
+in
+
+{
+
+  install = forEachSystem (system:
+    with import (nixpkgs + "/nixos/lib/testing-python.nix") { inherit system; };
+    simpleTest {
+      name = "hydra-install";
+      nodes.machine = hydraServer;
+      testScript =
+        ''
+          machine.wait_for_job("hydra-init")
+          machine.wait_for_job("hydra-server")
+          machine.wait_for_job("hydra-evaluator")
+          machine.wait_for_job("hydra-queue-runner")
+          machine.wait_for_open_port(3000)
+          machine.succeed("curl --fail http://localhost:3000/")
+        '';
+    });
+
+  notifications = forEachSystem (system:
+    with import (nixpkgs + "/nixos/lib/testing-python.nix") { inherit system; };
+    simpleTest {
+      name = "hydra-notifications";
+      nodes.machine = {
+        imports = [ hydraServer ];
+        services.hydra-dev.extraConfig = ''
+          <influxdb>
+            url = http://127.0.0.1:8086
+            db = hydra
+          </influxdb>
+        '';
+        services.influxdb.enable = true;
+      };
+      testScript = ''
+        machine.wait_for_job("hydra-init")
+
+        # Create an admin account and some other state.
+        machine.succeed(
+            """
+                su - hydra -c "hydra-create-user root --email-address 'alice@example.org' --password foobar --role admin"
+                mkdir /run/jobset
+                chmod 755 /run/jobset
+                cp ${./t/jobs/api-test.nix} /run/jobset/default.nix
+                chmod 644 /run/jobset/default.nix
+                chown -R hydra /run/jobset
+        """
+        )
+
+        # Wait until InfluxDB can receive web requests
+        machine.wait_for_job("influxdb")
+        machine.wait_for_open_port(8086)
+
+        # Create an InfluxDB database where hydra will write to
+        machine.succeed(
+            "curl -XPOST 'http://127.0.0.1:8086/query' "
+            + "--data-urlencode 'q=CREATE DATABASE hydra'"
+        )
+
+        # Wait until hydra-server can receive HTTP requests
+        machine.wait_for_job("hydra-server")
+        machine.wait_for_open_port(3000)
+
+        # Setup the project and jobset
+        machine.succeed(
+            "su - hydra -c 'perl -I ${config.services.hydra-dev.package.perlDeps}/lib/perl5/site_perl ${./t/setup-notifications-jobset.pl}' >&2"
+        )
+
+        # Wait until hydra has build the job and
+        # the InfluxDBNotification plugin uploaded its notification to InfluxDB
+        machine.wait_until_succeeds(
+            "curl -s -H 'Accept: application/csv' "
+            + "-G 'http://127.0.0.1:8086/query?db=hydra' "
+            + "--data-urlencode 'q=SELECT * FROM hydra_build_status' | grep success"
+        )
+      '';
+    });
+
+  gitea = forEachSystem (system:
+    let pkgs = nixpkgs.legacyPackages.${system}; in
+    with import (nixpkgs + "/nixos/lib/testing-python.nix") { inherit system; };
+    makeTest {
+      name = "hydra-gitea";
+      nodes.machine = { pkgs, ... }: {
+        imports = [ hydraServer ];
+        services.hydra-dev.extraConfig = ''
+          <gitea_authorization>
+          root=d7f16a3412e01a43a414535b16007c6931d3a9c7
+          </gitea_authorization>
+        '';
+        nixpkgs.config.permittedInsecurePackages = [ "gitea-1.19.4" ];
+        nix = {
+          settings.substituters = [ ];
+        };
+        services.gitea = {
+          enable = true;
+          database.type = "postgres";
+          settings = {
+            service.DISABLE_REGISTRATION = true;
+            server.HTTP_PORT = 3001;
+          };
+        };
+        services.openssh.enable = true;
+        environment.systemPackages = with pkgs; [ gitea git jq gawk ];
+        networking.firewall.allowedTCPPorts = [ 3000 ];
+      };
+      skipLint = true;
+      testScript =
+        let
+          scripts.mktoken = pkgs.writeText "token.sql" ''
+            INSERT INTO access_token (id, uid, name, created_unix, updated_unix, token_hash, token_salt, token_last_eight, scope) VALUES (1, 1, 'hydra', 1617107360, 1617107360, 'a930f319ca362d7b49a4040ac0af74521c3a3c3303a86f327b01994430672d33b6ec53e4ea774253208686c712495e12a486', 'XRjWE9YW0g', '31d3a9c7', 'all');
+          '';
+
+          scripts.git-setup = pkgs.writeShellScript "setup.sh" ''
+            set -x
+            mkdir -p /tmp/repo $HOME/.ssh
+            cat ${snakeoilKeypair.privkey} > $HOME/.ssh/privk
+            chmod 0400 $HOME/.ssh/privk
+            git -C /tmp/repo init
+            cp ${smallDrv} /tmp/repo/jobset.nix
+            git -C /tmp/repo add .
+            git config --global user.email test@localhost
+            git config --global user.name test
+            git -C /tmp/repo commit -m 'Initial import'
+            git -C /tmp/repo remote add origin gitea@machine:root/repo
+            GIT_SSH_COMMAND='ssh -i $HOME/.ssh/privk -o StrictHostKeyChecking=no' \
+              git -C /tmp/repo push origin master
+            git -C /tmp/repo log >&2
+          '';
+
+          scripts.hydra-setup = pkgs.writeShellScript "hydra.sh" ''
+            set -x
+            su -l hydra -c "hydra-create-user root --email-address \
+              'alice@example.org' --password foobar --role admin"
+
+            URL=http://localhost:3000
+            USERNAME="root"
+            PASSWORD="foobar"
+            PROJECT_NAME="trivial"
+            JOBSET_NAME="trivial"
+            mycurl() {
+              curl --referer $URL -H "Accept: application/json" \
+                -H "Content-Type: application/json" $@
+            }
+
+            cat >data.json <<EOF
+            { "username": "$USERNAME", "password": "$PASSWORD" }
+            EOF
+            mycurl -X POST -d '@data.json' $URL/login -c hydra-cookie.txt
+
+            cat >data.json <<EOF
+            {
+              "displayname":"Trivial",
+              "enabled":"1",
+              "visible":"1"
+            }
+            EOF
+            mycurl --silent -X PUT $URL/project/$PROJECT_NAME \
+              -d @data.json -b hydra-cookie.txt
+
+            cat >data.json <<EOF
+            {
+              "description": "Trivial",
+              "checkinterval": "60",
+              "enabled": "1",
+              "visible": "1",
+              "keepnr": "1",
+              "enableemail": true,
+              "emailoverride": "hydra@localhost",
+              "type": 0,
+              "nixexprinput": "git",
+              "nixexprpath": "jobset.nix",
+              "inputs": {
+                "git": {"value": "http://localhost:3001/root/repo.git", "type": "git"},
+                "gitea_repo_name": {"value": "repo", "type": "string"},
+                "gitea_repo_owner": {"value": "root", "type": "string"},
+                "gitea_status_repo": {"value": "git", "type": "string"},
+                "gitea_http_url": {"value": "http://localhost:3001", "type": "string"}
+              }
+            }
+            EOF
+
+            mycurl --silent -X PUT $URL/jobset/$PROJECT_NAME/$JOBSET_NAME \
+              -d @data.json -b hydra-cookie.txt
+          '';
+
+          api_token = "d7f16a3412e01a43a414535b16007c6931d3a9c7";
+
+          snakeoilKeypair = {
+            privkey = pkgs.writeText "privkey.snakeoil" ''
+              -----BEGIN EC PRIVATE KEY-----
+              MHcCAQEEIHQf/khLvYrQ8IOika5yqtWvI0oquHlpRLTZiJy5dRJmoAoGCCqGSM49
+              AwEHoUQDQgAEKF0DYGbBwbj06tA3fd/+yP44cvmwmHBWXZCKbS+RQlAKvLXMWkpN
+              r1lwMyJZoSGgBHoUahoYjTh9/sJL7XLJtA==
+              -----END EC PRIVATE KEY-----
+            '';
+
+            pubkey = pkgs.lib.concatStrings [
+              "ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHA"
+              "yNTYAAABBBChdA2BmwcG49OrQN33f/sj+OHL5sJhwVl2Qim0vkUJQCry1zFpKTa"
+              "9ZcDMiWaEhoAR6FGoaGI04ff7CS+1yybQ= sakeoil"
+            ];
+          };
+
+          smallDrv = pkgs.writeText "jobset.nix" ''
+            { trivial = builtins.derivation {
+                name = "trivial";
+                system = "${system}";
+                builder = "/bin/sh";
+                allowSubstitutes = false;
+                preferLocalBuild = true;
+                args = ["-c" "echo success > $out; exit 0"];
+              };
+             }
+          '';
+        in
+        ''
+          import json
+
+          machine.start()
+          machine.wait_for_unit("multi-user.target")
+          machine.wait_for_open_port(3000)
+          machine.wait_for_open_port(3001)
+
+          machine.succeed(
+              "su -l gitea -c 'GITEA_WORK_DIR=/var/lib/gitea gitea admin user create "
+              + "--username root --password root --email test@localhost'"
+          )
+          machine.succeed("su -l postgres -c 'psql gitea < ${scripts.mktoken}'")
+
+          machine.succeed(
+              "curl --fail -X POST http://localhost:3001/api/v1/user/repos "
+              + "-H 'Accept: application/json' -H 'Content-Type: application/json' "
+              + f"-H 'Authorization: token ${api_token}'"
+              + ' -d \'{"auto_init":false, "description":"string", "license":"mit", "name":"repo", "private":false}\'''
+          )
+
+          machine.succeed(
+              "curl --fail -X POST http://localhost:3001/api/v1/user/keys "
+              + "-H 'Accept: application/json' -H 'Content-Type: application/json' "
+              + f"-H 'Authorization: token ${api_token}'"
+              + ' -d \'{"key":"${snakeoilKeypair.pubkey}","read_only":true,"title":"SSH"}\'''
+          )
+
+          machine.succeed(
+              "${scripts.git-setup}"
+          )
+
+          machine.succeed(
+              "${scripts.hydra-setup}"
+          )
+
+          machine.wait_until_succeeds(
+              'curl -Lf -s http://localhost:3000/build/1 -H "Accept: application/json" '
+              + '|  jq .buildstatus | xargs test 0 -eq'
+          )
+
+          data = machine.succeed(
+              'curl -Lf -s "http://localhost:3001/api/v1/repos/root/repo/statuses/$(cd /tmp/repo && git show | head -n1 | awk "{print \\$2}")" '
+              + "-H 'Accept: application/json' -H 'Content-Type: application/json' "
+              + f"-H 'Authorization: token ${api_token}'"
+          )
+
+          response = json.loads(data)
+
+          assert len(response) == 2, "Expected exactly three status updates for latest commit (queued, finished)!"
+          assert response[0]['status'] == "success", "Expected finished status to be success!"
+          assert response[1]['status'] == "pending", "Expected queued status to be pending!"
+
+          machine.shutdown()
+        '';
+    });
+
+  validate-openapi = forEachSystem (system:
+    let pkgs = nixpkgs.legacyPackages.${system}; in
+    pkgs.runCommand "validate-openapi"
+    { buildInputs = [ pkgs.openapi-generator-cli ]; }
+    ''
+      openapi-generator-cli validate -i ${./hydra-api.yaml}
+      touch $out
+    '');
+
+}
--- a/package.nix
+++ b/package.nix
@@ -9,10 +9,12 @@
 , perlPackages

 , nix
+, nix-perl-bindings
 , git

 , makeWrapper
-, autoreconfHook
+, meson
+, ninja
 , nukeReferences
 , pkg-config
 , mdbook
@@ -59,7 +61,7 @@ let
    name = "hydra-perl-deps";
    paths = lib.closePropagation
      ([
-        nix.perl-bindings
+        nix-perl-bindings
        git
      ] ++ (with perlPackages; [
        AuthenSASL
@@ -87,10 +89,10 @@ let
        DateTime
        DBDPg
        DBDSQLite
-        DBIxClassHelpers
        DigestSHA1
        EmailMIME
        EmailSender
+        FileCopyRecursive
        FileLibMagic
        FileSlurper
        FileWhich
@@ -138,28 +140,24 @@ stdenv.mkDerivation (finalAttrs: {
  src = fileset.toSource {
    root = ./.;
    fileset = fileset.unions ([
-      ./version.txt
-      ./configure.ac
-      ./Makefile.am
-      ./src
      ./doc
-      ./nixos-modules/hydra.nix
-      # These are always needed to appease Automake
-      ./t/Makefile.am
-      ./t/jobs/config.nix.in
-      ./t/jobs/declarative/project.json.in
-    ] ++ lib.optionals finalAttrs.doCheck [
+      ./meson.build
+      ./nixos-modules
+      ./src
      ./t
+      ./version.txt
      ./.perlcriticrc
-      ./.yath.rc
    ]);
  };

+  outputs = [ "out" "doc" ];
+
  strictDeps = true;

  nativeBuildInputs = [
    makeWrapper
-    autoreconfHook
+    meson
+    ninja
    nukeReferences
    pkg-config
    mdbook
@@ -225,6 +223,12 @@ stdenv.mkDerivation (finalAttrs: {

  OPENLDAP_ROOT = openldap;

+  mesonBuildType = "release";
+
+  postPatch = ''
+    patchShebangs .
+  '';
+
  shellHook = ''
    pushd $(git rev-parse --show-toplevel) >/dev/null

@@ -238,14 +242,11 @@ stdenv.mkDerivation (finalAttrs: {
    popd >/dev/null
  '';

-  NIX_LDFLAGS = [ "-lpthread" ];
-
-  enableParallelBuilding = true;
-
  doCheck = true;

+  mesonCheckFlags = [ "--verbose" ];
+
  preCheck = ''
-    patchShebangs .
    export LOGNAME=''${LOGNAME:-foo}
    # set $HOME for bzr so it can create its trace file
    export HOME=$(mktemp -d)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,3 +0,0 @@
-SUBDIRS = hydra-evaluator hydra-eval-jobs hydra-queue-runner sql script lib root ttf
-BOOTCLEAN_SUBDIRS = $(SUBDIRS)
-DIST_SUBDIRS      = $(SUBDIRS)
--- a/src/hydra-eval-jobs/Makefile.am
+++ b/src/hydra-eval-jobs/Makefile.am
@@ -1,5 +0,0 @@
-bin_PROGRAMS = hydra-eval-jobs
-
-hydra_eval_jobs_SOURCES = hydra-eval-jobs.cc
-hydra_eval_jobs_LDADD = $(NIX_LIBS) -lnixcmd
-hydra_eval_jobs_CXXFLAGS = $(NIX_CFLAGS) -I ../libhydra
--- a/src/hydra-eval-jobs/hydra-eval-jobs.cc
+++ b/src/hydra-eval-jobs/hydra-eval-jobs.cc
@@ -6,6 +6,7 @@
 #include "shared.hh"
 #include "store-api.hh"
 #include "eval.hh"
+#include "eval-gc.hh"
 #include "eval-inline.hh"
 #include "eval-settings.hh"
 #include "signals.hh"
@@ -89,7 +90,7 @@ struct MyArgs : MixEvalArgs, MixCommonArgs, RootArgs

 static MyArgs myArgs;

-static std::string queryMetaStrings(EvalState & state, DrvInfo & drv, const std::string & name, const std::string & subAttribute)
+static std::string queryMetaStrings(EvalState & state, PackageInfo & drv, const std::string & name, const std::string & subAttribute)
 {
    Strings res;
    std::function<void(Value & v)> rec;
@@ -102,8 +103,8 @@ static std::string queryMetaStrings(EvalState & state, DrvInfo & drv, const std:
            for (unsigned int n = 0; n < v.listSize(); ++n)
                rec(*v.listElems()[n]);
        else if (v.type() == nAttrs) {
-            auto a = v.attrs->find(state.symbols.create(subAttribute));
-            if (a != v.attrs->end())
+            auto a = v.attrs()->find(state.symbols.create(subAttribute));
+            if (a != v.attrs()->end())
                res.push_back(std::string(state.forceString(*a->value, a->pos, "while evaluating meta attributes")));
        }
    };
@@ -125,11 +126,14 @@ static void worker(
    if (myArgs.flake) {
        using namespace flake;

-        auto flakeRef = parseFlakeRef(myArgs.releaseExpr);
+        auto [flakeRef, fragment, outputSpec] = parseFlakeRefWithFragmentAndExtendedOutputsSpec(fetchSettings, myArgs.releaseExpr, absPath("."));

        auto vFlake = state.allocValue();

-        auto lockedFlake = lockFlake(state, flakeRef,
+        auto lockedFlake = lockFlake(
+                flakeSettings,
+                state,
+                flakeRef,
            LockFlags {
                .updateLockFile = false,
                .useRegistries = false,
@@ -138,12 +142,12 @@ static void worker(

        callFlake(state, lockedFlake, *vFlake);

-        auto vOutputs = vFlake->attrs->get(state.symbols.create("outputs"))->value;
+        auto vOutputs = vFlake->attrs()->get(state.symbols.create("outputs"))->value;
        state.forceValue(*vOutputs, noPos);

-        auto aHydraJobs = vOutputs->attrs->get(state.symbols.create("hydraJobs"));
+        auto aHydraJobs = vOutputs->attrs()->get(state.symbols.create("hydraJobs"));
        if (!aHydraJobs)
-            aHydraJobs = vOutputs->attrs->get(state.symbols.create("checks"));
+            aHydraJobs = vOutputs->attrs()->get(state.symbols.create("checks"));
        if (!aHydraJobs)
            throw Error("flake '%s' does not provide any Hydra jobs or checks", flakeRef);

@@ -181,11 +185,11 @@ static void worker(
                // CA derivations do not have static output paths, so we
                // have to defensively not query output paths in case we
                // encounter one.
-                DrvInfo::Outputs outputs = drv->queryOutputs(
+                PackageInfo::Outputs outputs = drv->queryOutputs(
                    !experimentalFeatureSettings.isEnabled(Xp::CaDerivations));

                if (drv->querySystem() == "unknown")
-                    throw EvalError("derivation must have a 'system' attribute");
+                    state.error<EvalError>("derivation must have a 'system' attribute").debugThrow();

                auto drvPath = state.store->printStorePath(drv->requireDrvPath());

@@ -204,11 +208,11 @@ static void worker(
                job["isChannel"] = drv->queryMetaBool("isHydraChannel", false);

                /* If this is an aggregate, then get its constituents. */
-                auto a = v->attrs->get(state.symbols.create("_hydraAggregate"));
+                auto a = v->attrs()->get(state.symbols.create("_hydraAggregate"));
                if (a && state.forceBool(*a->value, a->pos, "while evaluating the `_hydraAggregate` attribute")) {
-                    auto a = v->attrs->get(state.symbols.create("constituents"));
+                    auto a = v->attrs()->get(state.symbols.create("constituents"));
                    if (!a)
-                        throw EvalError("derivation must have a ‘constituents’ attribute");
+                        state.error<EvalError>("derivation must have a ‘constituents’ attribute").debugThrow();

                    NixStringContext context;
                    state.coerceToString(a->pos, *a->value, context, "while evaluating the `constituents` attribute", true, false);
@@ -260,7 +264,7 @@ static void worker(
            else if (v->type() == nAttrs) {
                auto attrs = nlohmann::json::array();
                StringSet ss;
-                for (auto & i : v->attrs->lexicographicOrder(state.symbols)) {
+                for (auto & i : v->attrs()->lexicographicOrder(state.symbols)) {
                    std::string name(state.symbols[i->name]);
                    if (name.find(' ') != std::string::npos) {
                        printError("skipping job with illegal name '%s'", name);
@@ -274,7 +278,7 @@ static void worker(
            else if (v->type() == nNull)
                ;

-            else throw TypeError("attribute '%s' is %s, which is not supported", attrPath, showType(*v));
+            else state.error<TypeError>("attribute '%s' is %s, which is not supported", attrPath, showType(*v)).debugThrow();

        } catch (EvalError & e) {
            auto msg = e.msg();
@@ -368,7 +372,11 @@ int main(int argc, char * * argv)
                            ]()
                            {
                                try {
-                                    EvalState state(myArgs.searchPath, openStore());
+                                    auto evalStore = myArgs.evalStoreUrl
+                                             ? openStore(*myArgs.evalStoreUrl)
+                                             : openStore();
+                                    EvalState state(myArgs.lookupPath,
+                                            evalStore, fetchSettings, evalSettings);
                                    Bindings & autoArgs = *myArgs.getAutoArgs(state);
                                    worker(state, autoArgs, *to, *from);
                                } catch (Error & e) {
--- a/src/hydra-eval-jobs/meson.build
+++ b/src/hydra-eval-jobs/meson.build
@@ -0,0 +1,8 @@
+hydra_eval_jobs = executable('hydra-eval-jobs',
+  'hydra-eval-jobs.cc',
+  dependencies: [
+    libhydra_dep,
+    nix_dep,
+  ],
+  install: true,
+)
--- a/src/hydra-evaluator/Makefile.am
+++ b/src/hydra-evaluator/Makefile.am
@@ -1,5 +0,0 @@
-bin_PROGRAMS = hydra-evaluator
-
-hydra_evaluator_SOURCES = hydra-evaluator.cc
-hydra_evaluator_LDADD = $(NIX_LIBS) -lpqxx
-hydra_evaluator_CXXFLAGS = $(NIX_CFLAGS) -Wall -I ../libhydra -Wno-deprecated-declarations
--- a/src/hydra-evaluator/hydra-evaluator.cc
+++ b/src/hydra-evaluator/hydra-evaluator.cc
@@ -38,7 +38,7 @@ class JobsetId {
    friend bool operator!= (const JobsetId & lhs, const JobsetName & rhs);

    std::string display() const {
-        return str(format("%1%:%2% (jobset#%3%)") % project % jobset % id);
+        return boost::str(boost::format("%1%:%2% (jobset#%3%)") % project % jobset % id);
    }
 };
 bool operator==(const JobsetId & lhs, const JobsetId & rhs)
--- a/src/hydra-evaluator/meson.build
+++ b/src/hydra-evaluator/meson.build
@@ -0,0 +1,9 @@
+hydra_evaluator = executable('hydra-evaluator',
+  'hydra-evaluator.cc',
+  dependencies: [
+    libhydra_dep,
+    nix_dep,
+    pqxx_dep,
+  ],
+  install: true,
+)
--- a/src/hydra-queue-runner/Makefile.am
+++ b/src/hydra-queue-runner/Makefile.am
@@ -1,8 +0,0 @@
-bin_PROGRAMS = hydra-queue-runner
-
-hydra_queue_runner_SOURCES = hydra-queue-runner.cc queue-monitor.cc dispatcher.cc \
- builder.cc build-result.cc build-remote.cc \
- hydra-build-result.hh counter.hh state.hh db.hh \
- nar-extractor.cc nar-extractor.hh
-hydra_queue_runner_LDADD = $(NIX_LIBS) -lpqxx -lprometheus-cpp-pull -lprometheus-cpp-core
-hydra_queue_runner_CXXFLAGS = $(NIX_CFLAGS) -Wall -I ../libhydra -Wno-deprecated-declarations
--- a/src/hydra-queue-runner/build-remote.cc
+++ b/src/hydra-queue-runner/build-remote.cc
@@ -8,6 +8,7 @@
 #include "build-result.hh"
 #include "path.hh"
 #include "serve-protocol.hh"
+#include "serve-protocol-impl.hh"
 #include "state.hh"
 #include "current-process.hh"
 #include "processes.hh"
@@ -20,12 +21,6 @@

 using namespace nix;

-
-static void append(Strings & dst, const Strings & src)
-{
-    dst.insert(dst.end(), src.begin(), src.end());
-}
-
 namespace nix::build_remote {

 static Strings extraStoreArgs(std::string & machine)
@@ -48,63 +43,31 @@ static Strings extraStoreArgs(std::string & machine)
    return result;
 }

-static void openConnection(::Machine::ptr machine, Path tmpDir, int stderrFD, SSHMaster::Connection & child)
+static std::unique_ptr<SSHMaster::Connection> openConnection(
+    ::Machine::ptr machine, SSHMaster & master)
 {
-    std::string pgmName;
-    Pipe to, from;
-    to.create();
-    from.create();
-
-    Strings argv;
+    Strings command = {"nix-store", "--serve", "--write"};
    if (machine->isLocalhost()) {
-        pgmName = "nix-store";
-        argv = {"nix-store", "--builders", "", "--serve", "--write"};
+        command.push_back("--builders");
+        command.push_back("");
    } else {
-        pgmName = "ssh";
-        auto sshName = machine->sshName;
-        Strings extraArgs = extraStoreArgs(sshName);
-        argv = {"ssh", sshName};
-        if (machine->sshKey != "") append(argv, {"-i", machine->sshKey});
-        if (machine->sshPublicHostKey != "") {
-            Path fileName = tmpDir + "/host-key";
-            auto p = machine->sshName.find("@");
-            std::string host = p != std::string::npos ? std::string(machine->sshName, p + 1) : machine->sshName;
-            writeFile(fileName, host + " " + machine->sshPublicHostKey + "\n");
-            append(argv, {"-oUserKnownHostsFile=" + fileName});
-        }
-        append(argv,
-            { "-x", "-a", "-oBatchMode=yes", "-oConnectTimeout=60", "-oTCPKeepAlive=yes"
-            , "--", "nix-store", "--serve", "--write" });
-        append(argv, extraArgs);
+        command.splice(command.end(), extraStoreArgs(machine->sshName));
    }

-    child.sshPid = startProcess([&]() {
-        restoreProcessContext();
-
-        if (dup2(to.readSide.get(), STDIN_FILENO) == -1)
-            throw SysError("cannot dup input pipe to stdin");
-
-        if (dup2(from.writeSide.get(), STDOUT_FILENO) == -1)
-            throw SysError("cannot dup output pipe to stdout");
-
-        if (dup2(stderrFD, STDERR_FILENO) == -1)
-            throw SysError("cannot dup stderr");
-
-        execvp(argv.front().c_str(), (char * *) stringsToCharPtrs(argv).data()); // FIXME: remove cast
-
-        throw SysError("cannot start %s", pgmName);
+    auto ret = master.startCommand(std::move(command), {
+        "-a", "-oBatchMode=yes", "-oConnectTimeout=60", "-oTCPKeepAlive=yes"
    });

-    to.readSide = -1;
-    from.writeSide = -1;
-
-    child.in = to.writeSide.release();
-    child.out = from.readSide.release();
-
    // XXX: determine the actual max value we can use from /proc.
+
+    // FIXME: Should this be upstreamed into `startCommand` in Nix?
+
    int pipesize = 1024 * 1024;
-    fcntl(child.in.get(), F_SETPIPE_SZ, &pipesize);
-    fcntl(child.out.get(), F_SETPIPE_SZ, &pipesize);
+
+    fcntl(ret->in.get(), F_SETPIPE_SZ, &pipesize);
+    fcntl(ret->out.get(), F_SETPIPE_SZ, &pipesize);
+
+    return ret;
 }


@@ -122,13 +85,10 @@ static void copyClosureTo(
       garbage-collect paths that are already there. Optionally, ask
       the remote host to substitute missing paths. */
    // FIXME: substitute output pollutes our build log
-    conn.to << ServeProto::Command::QueryValidPaths << 1 << useSubstitutes;
-    ServeProto::write(destStore, conn, closure);
-    conn.to.flush();
-
    /* Get back the set of paths that are already valid on the remote
       host. */
-    auto present = ServeProto::Serialise<StorePathSet>::read(destStore, conn);
+    auto present = conn.queryValidPaths(
+        destStore, true, closure, useSubstitutes);

    if (present.size() == closure.size()) return;

@@ -153,7 +113,7 @@ static void copyClosureTo(


 // FIXME: use Store::topoSortPaths().
-static StorePaths reverseTopoSortPaths(const std::map<StorePath, ValidPathInfo> & paths)
+static StorePaths reverseTopoSortPaths(const std::map<StorePath, UnkeyedValidPathInfo> & paths)
 {
    StorePaths sorted;
    StorePathSet visited;
@@ -194,28 +154,6 @@ static std::pair<Path, AutoCloseFD> openLogFile(const std::string & logDir, cons
    return {std::move(logFile), std::move(logFD)};
 }

-/**
- * @param conn is not fully initialized; it is this functions job to set
- * the `remoteVersion` field after the handshake is completed.
- * Therefore, no `ServeProto::Serialize` functions can be used until
- * that field is set.
- */
-static void handshake(::Machine::Connection & conn, unsigned int repeats)
-{
-    conn.to << SERVE_MAGIC_1 << 0x206;
-    conn.to.flush();
-
-    unsigned int magic = readInt(conn.from);
-    if (magic != SERVE_MAGIC_2)
-        throw Error("protocol mismatch with ‘nix-store --serve’ on ‘%1%’", conn.machine->sshName);
-    conn.remoteVersion = readInt(conn.from);
-    // Now `conn` is initialized.
-    if (GET_PROTOCOL_MAJOR(conn.remoteVersion) != 0x200)
-        throw Error("unsupported ‘nix-store --serve’ protocol version on ‘%1%’", conn.machine->sshName);
-    if (GET_PROTOCOL_MINOR(conn.remoteVersion) < 3 && repeats > 0)
-        throw Error("machine ‘%1%’ does not support repeating a build; please upgrade it to Nix 1.12", conn.machine->sshName);
-}
-
 static BasicDerivation sendInputs(
    State & state,
    Step & step,
@@ -286,21 +224,11 @@ static BuildResult performBuild(
    Store & localStore,
    StorePath drvPath,
    const BasicDerivation & drv,
-    const State::BuildOptions & options,
+    const ServeProto::BuildOptions & options,
    counter & nrStepsBuilding
 )
 {
-    conn.to << ServeProto::Command::BuildDerivation << localStore.printStorePath(drvPath);
-    writeDerivation(conn.to, localStore, drv);
-    conn.to << options.maxSilentTime << options.buildTimeout;
-    if (GET_PROTOCOL_MINOR(conn.remoteVersion) >= 2)
-        conn.to << options.maxLogSize;
-    if (GET_PROTOCOL_MINOR(conn.remoteVersion) >= 3) {
-        conn.to
-            << options.repeats // == build-repeat
-            << options.enforceDeterminism;
-    }
-    conn.to.flush();
+    conn.putBuildDerivationRequest(localStore, drvPath, drv, options);

    BuildResult result;

@@ -350,7 +278,7 @@ static BuildResult performBuild(
    return result;
 }

-static std::map<StorePath, ValidPathInfo> queryPathInfos(
+static std::map<StorePath, UnkeyedValidPathInfo> queryPathInfos(
    ::Machine::Connection & conn,
    Store & localStore,
    StorePathSet & outputs,
@@ -359,30 +287,18 @@ static std::map<StorePath, ValidPathInfo> queryPathInfos(
 {

    /* Get info about each output path. */
-    std::map<StorePath, ValidPathInfo> infos;
+    std::map<StorePath, UnkeyedValidPathInfo> infos;
    conn.to << ServeProto::Command::QueryPathInfos;
    ServeProto::write(localStore, conn, outputs);
    conn.to.flush();
    while (true) {
        auto storePathS = readString(conn.from);
        if (storePathS == "") break;
-        auto deriver = readString(conn.from); // deriver
-        auto references = ServeProto::Serialise<StorePathSet>::read(localStore, conn);
-        readLongLong(conn.from); // download size
-        auto narSize = readLongLong(conn.from);
-        auto narHash = Hash::parseAny(readString(conn.from), htSHA256);
-        auto ca = ContentAddress::parseOpt(readString(conn.from));
-        readStrings<StringSet>(conn.from); // sigs
-        ValidPathInfo info(localStore.parseStorePath(storePathS), narHash);
-        assert(outputs.count(info.path));
-        info.references = references;
-        info.narSize = narSize;
+
+        auto storePath = localStore.parseStorePath(storePathS);
+        auto info = ServeProto::Serialise<UnkeyedValidPathInfo>::read(localStore, conn);
        totalNarSize += info.narSize;
-        info.narHash = narHash;
-        info.ca = ca;
-        if (deriver != "")
-            info.deriver = localStore.parseStorePath(deriver);
-        infos.insert_or_assign(info.path, info);
+        infos.insert_or_assign(std::move(storePath), std::move(info));
    }

    return infos;
@@ -423,14 +339,16 @@ static void copyPathsFromRemote(
    NarMemberDatas & narMembers,
    Store & localStore,
    Store & destStore,
-    const std::map<StorePath, ValidPathInfo> & infos
+    const std::map<StorePath, UnkeyedValidPathInfo> & infos
 )
 {
      auto pathsSorted = reverseTopoSortPaths(infos);

      for (auto & path : pathsSorted) {
          auto & info = infos.find(path)->second;
-          copyPathFromRemote(conn, narMembers, localStore, destStore, info);
+          copyPathFromRemote(
+              conn, narMembers, localStore, destStore,
+              ValidPathInfo { path, info });
      }

 }
@@ -494,21 +412,10 @@ void RemoteResult::updateWithBuildResult(const nix::BuildResult & buildResult)

 }

-/* Utility guard object to auto-release a semaphore on destruction. */
-template <typename T>
-class SemaphoreReleaser {
-public:
-    SemaphoreReleaser(T* s) : sem(s) {}
-    ~SemaphoreReleaser() { sem->release(); }
-
-private:
-    T* sem;
-};

 void State::buildRemote(ref<Store> destStore,
-    MachineReservation::ptr & reservation,
    ::Machine::ptr machine, Step::ptr step,
-    const BuildOptions & buildOptions,
+    const ServeProto::BuildOptions & buildOptions,
    RemoteResult & result, std::shared_ptr<ActiveStep> activeStep,
    std::function<void(StepState)> updateStep,
    NarMemberDatas & narMembers)
@@ -519,21 +426,26 @@ void State::buildRemote(ref<Store> destStore,
    AutoDelete logFileDel(logFile, false);
    result.logFile = logFile;

-    nix::Path tmpDir = createTempDir();
-    AutoDelete tmpDirDel(tmpDir, true);
-
    try {

        updateStep(ssConnecting);

+        SSHMaster master {
+            machine->sshName,
+            machine->sshKey,
+            machine->sshPublicHostKey,
+            false, // no SSH master yet
+            false, // no compression yet
+            logFD.get(),
+        };
+
        // FIXME: rewrite to use Store.
-        SSHMaster::Connection child;
-        build_remote::openConnection(machine, tmpDir, logFD.get(), child);
+        auto child = build_remote::openConnection(machine, master);

        {
            auto activeStepState(activeStep->state_.lock());
            if (activeStepState->cancelled) throw Error("step cancelled");
-            activeStepState->pid = child.sshPid;
+            activeStepState->pid = child->sshPid;
        }

        Finally clearPid([&]() {
@@ -549,9 +461,13 @@ void State::buildRemote(ref<Store> destStore,
        });

        ::Machine::Connection conn {
-            .from = child.out.get(),
-            .to = child.in.get(),
-            .machine = machine,
+            {
+                .to = child->in.get(),
+                .from = child->out.get(),
+                /* Handshake. */
+                .remoteVersion = 0xdadbeef, // FIXME avoid dummy initialize
+            },
+            /*.machine =*/ machine,
        };

        Finally updateStats([&]() {
@@ -559,14 +475,26 @@ void State::buildRemote(ref<Store> destStore,
            bytesSent += conn.to.written;
        });

+        constexpr ServeProto::Version our_version = 0x206;
+
        try {
-          build_remote::handshake(conn, buildOptions.repeats);
+            conn.remoteVersion = decltype(conn)::handshake(
+                conn.to,
+                conn.from,
+                our_version,
+                machine->sshName);
        } catch (EndOfFile & e) {
-            child.sshPid.wait();
+            child->sshPid.wait();
            std::string s = chomp(readFile(result.logFile));
            throw Error("cannot connect to ‘%1%’: %2%", machine->sshName, s);
        }

+        // Do not attempt to speak a newer version of the protocol.
+        //
+        // Per https://github.com/NixOS/nix/issues/9584 should be handled as
+        // part of `handshake` in upstream nix.
+        conn.remoteVersion = std::min(conn.remoteVersion, our_version);
+
        {
            auto info(machine->state->connectInfo.lock());
            info->consecutiveFailures = 0;
@@ -623,23 +551,6 @@ void State::buildRemote(ref<Store> destStore,
            result.logFile = "";
        }

-        /* Throttle CPU-bound work. Opportunistically skip updating the current
-         * step, since this requires a DB roundtrip. */
-        if (!localWorkThrottler.try_acquire()) {
-            updateStep(ssWaitingForLocalSlot);
-            localWorkThrottler.acquire();
-        }
-        SemaphoreReleaser releaser(&localWorkThrottler);
-
-        /* Once we've started copying outputs, release the machine reservation
-         * so further builds can happen. We do not release the machine earlier
-         * to avoid situations where the queue runner is bottlenecked on
-         * copying outputs and we end up building too many things that we
-         * haven't been able to allow copy slots for. */
-        assert(reservation.unique());
-        reservation = 0;
-        wakeDispatcher();
-
        StorePathSet outputs;
        for (auto & [_, realisation] : buildResult.builtOutputs)
            outputs.insert(realisation.outPath);
@@ -686,8 +597,8 @@ void State::buildRemote(ref<Store> destStore,
        }

        /* Shut down the connection. */
-        child.in = -1;
-        child.sshPid.wait();
+        child->in = -1;
+        child->sshPid.wait();

    } catch (Error & e) {
        /* Disable this machine until a certain period of time has
--- a/src/hydra-queue-runner/builder.cc
+++ b/src/hydra-queue-runner/builder.cc
@@ -46,12 +46,10 @@ void State::builder(MachineReservation::ptr reservation)
        }
    }

-    /* If the machine hasn't been released yet, release and wake up the dispatcher. */
-    if (reservation) {
-        assert(reservation.unique());
-        reservation = 0;
-        wakeDispatcher();
-    }
+    /* Release the machine and wake up the dispatcher. */
+    assert(reservation.unique());
+    reservation = 0;
+    wakeDispatcher();

    /* If there was a temporary failure, retry the step after an
       exponentially increasing interval. */
@@ -74,11 +72,11 @@ void State::builder(MachineReservation::ptr reservation)


 State::StepResult State::doBuildStep(nix::ref<Store> destStore,
-    MachineReservation::ptr & reservation,
+    MachineReservation::ptr reservation,
    std::shared_ptr<ActiveStep> activeStep)
 {
-    auto step(reservation->step);
-    auto machine(reservation->machine);
+    auto & step(reservation->step);
+    auto & machine(reservation->machine);

    {
        auto step_(step->state.lock());
@@ -100,10 +98,13 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
       it). */
    BuildID buildId;
    std::optional<StorePath> buildDrvPath;
-    BuildOptions buildOptions;
-    buildOptions.repeats = step->isDeterministic ? 1 : 0;
-    buildOptions.maxLogSize = maxLogSize;
-    buildOptions.enforceDeterminism = step->isDeterministic;
+    // Other fields set below
+    nix::ServeProto::BuildOptions buildOptions {
+        .maxLogSize = maxLogSize,
+        .nrRepeats = step->isDeterministic ? 1u : 0u,
+        .enforceDeterminism = step->isDeterministic,
+        .keepFailed = false,
+    };

    auto conn(dbPool.get());

@@ -138,7 +139,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
            {
                auto i = jobsetRepeats.find(std::make_pair(build2->projectName, build2->jobsetName));
                if (i != jobsetRepeats.end())
-                    buildOptions.repeats = std::max(buildOptions.repeats, i->second);
+                    buildOptions.nrRepeats = std::max(buildOptions.nrRepeats, i->second);
            }
        }
        if (!build) build = *dependents.begin();
@@ -149,7 +150,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
        buildOptions.buildTimeout = build->buildTimeout;

        printInfo("performing step ‘%s’ %d times on ‘%s’ (needed by build %d and %d others)",
-            localStore->printStorePath(step->drvPath), buildOptions.repeats + 1, machine->sshName, buildId, (dependents.size() - 1));
+            localStore->printStorePath(step->drvPath), buildOptions.nrRepeats + 1, machine->sshName, buildId, (dependents.size() - 1));
    }

    if (!buildOneDone)
@@ -210,7 +211,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,

        try {
            /* FIXME: referring builds may have conflicting timeouts. */
-            buildRemote(destStore, reservation, machine, step, buildOptions, result, activeStep, updateStep, narMembers);
+            buildRemote(destStore, machine, step, buildOptions, result, activeStep, updateStep, narMembers);
        } catch (Error & e) {
            if (activeStep->state_.lock()->cancelled) {
                printInfo("marking step %d of build %d as cancelled", stepNr, buildId);
--- a/src/hydra-queue-runner/dispatcher.cc
+++ b/src/hydra-queue-runner/dispatcher.cc
@@ -2,6 +2,7 @@
 #include <cmath>
 #include <thread>
 #include <unordered_map>
+#include <unordered_set>

 #include "state.hh"

@@ -39,15 +40,13 @@ void State::dispatcher()
            printMsg(lvlDebug, "dispatcher woken up");
            nrDispatcherWakeups++;

-            auto t_before_work = std::chrono::steady_clock::now();
+            auto now1 = std::chrono::steady_clock::now();

            auto sleepUntil = doDispatch();

-            auto t_after_work = std::chrono::steady_clock::now();
+            auto now2 = std::chrono::steady_clock::now();

-            prom.dispatcher_time_spent_running.Increment(
-                std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count());
-            dispatchTimeMs += std::chrono::duration_cast<std::chrono::milliseconds>(t_after_work - t_before_work).count();
+            dispatchTimeMs += std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();

            /* Sleep until we're woken up (either because a runnable build
               is added, or because a build finishes). */
@@ -61,10 +60,6 @@ void State::dispatcher()
                *dispatcherWakeup_ = false;
            }

-            auto t_after_sleep = std::chrono::steady_clock::now();
-            prom.dispatcher_time_spent_waiting.Increment(
-                std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count());
-
        } catch (std::exception & e) {
            printError("dispatcher: %s", e.what());
            sleep(1);
@@ -133,8 +128,6 @@ system_time State::doDispatch()
           comparator is a partial ordering (see MachineInfo). */
        int highestGlobalPriority;
        int highestLocalPriority;
-        size_t numRequiredSystemFeatures;
-        size_t numRevDeps;
        BuildID lowestBuildID;

        StepInfo(Step::ptr step, Step::State & step_) : step(step)
@@ -143,8 +136,6 @@ system_time State::doDispatch()
                lowestShareUsed = std::min(lowestShareUsed, jobset->shareUsed());
            highestGlobalPriority = step_.highestGlobalPriority;
            highestLocalPriority = step_.highestLocalPriority;
-            numRequiredSystemFeatures = step->requiredSystemFeatures.size();
-            numRevDeps = step_.rdeps.size();
            lowestBuildID = step_.lowestBuildID;
        }
    };
@@ -197,8 +188,6 @@ system_time State::doDispatch()
                a.highestGlobalPriority != b.highestGlobalPriority ? a.highestGlobalPriority > b.highestGlobalPriority :
                a.lowestShareUsed != b.lowestShareUsed ? a.lowestShareUsed < b.lowestShareUsed :
                a.highestLocalPriority != b.highestLocalPriority ? a.highestLocalPriority > b.highestLocalPriority :
-                a.numRequiredSystemFeatures != b.numRequiredSystemFeatures ? a.numRequiredSystemFeatures > b.numRequiredSystemFeatures :
-                a.numRevDeps != b.numRevDeps ? a.numRevDeps > b.numRevDeps :
                a.lowestBuildID < b.lowestBuildID;
        });

@@ -243,11 +232,11 @@ system_time State::doDispatch()
        sort(machinesSorted.begin(), machinesSorted.end(),
            [](const MachineInfo & a, const MachineInfo & b) -> bool
            {
-                float ta = std::round(a.currentJobs / a.machine->speedFactorFloat);
-                float tb = std::round(b.currentJobs / b.machine->speedFactorFloat);
+                float ta = std::round(a.currentJobs / a.machine->speedFactor);
+                float tb = std::round(b.currentJobs / b.machine->speedFactor);
                return
                    ta != tb ? ta < tb :
-                    a.machine->speedFactorFloat != b.machine->speedFactorFloat ? a.machine->speedFactorFloat > b.machine->speedFactorFloat :
+                    a.machine->speedFactor != b.machine->speedFactor ? a.machine->speedFactor > b.machine->speedFactor :
                    a.currentJobs > b.currentJobs;
            });

--- a/src/hydra-queue-runner/hydra-queue-runner.cc
+++ b/src/hydra-queue-runner/hydra-queue-runner.cc
@@ -70,31 +70,10 @@ State::PromMetrics::PromMetrics()
            .Register(*registry)
            .Add({})
    )
-    , dispatcher_time_spent_running(
-        prometheus::BuildCounter()
-            .Name("hydraqueuerunner_dispatcher_time_spent_running")
-            .Help("Time (in micros) spent running the dispatcher")
-            .Register(*registry)
-            .Add({})
-    )
-    , dispatcher_time_spent_waiting(
-        prometheus::BuildCounter()
-            .Name("hydraqueuerunner_dispatcher_time_spent_waiting")
-            .Help("Time (in micros) spent waiting for the dispatcher to obtain work")
-            .Register(*registry)
-            .Add({})
-    )
-    , queue_monitor_time_spent_running(
-        prometheus::BuildCounter()
-            .Name("hydraqueuerunner_queue_monitor_time_spent_running")
-            .Help("Time (in micros) spent running the queue monitor")
-            .Register(*registry)
-            .Add({})
-    )
-    , queue_monitor_time_spent_waiting(
-        prometheus::BuildCounter()
-            .Name("hydraqueuerunner_queue_monitor_time_spent_waiting")
-            .Help("Time (in micros) spent waiting for the queue monitor to obtain work")
+    , queue_max_id(
+        prometheus::BuildGauge()
+            .Name("hydraqueuerunner_queue_max_build_id_info")
+            .Help("Maximum build record ID in the queue")
            .Register(*registry)
            .Add({})
    )
@@ -106,7 +85,6 @@ State::State(std::optional<std::string> metricsAddrOpt)
    : config(std::make_unique<HydraConfig>())
    , maxUnsupportedTime(config->getIntOption("max_unsupported_time", 0))
    , dbPool(config->getIntOption("max_db_connections", 128))
-    , localWorkThrottler(config->getIntOption("max_local_worker_threads", std::min(maxSupportedLocalWorkers, std::max(4u, std::thread::hardware_concurrency()) - 2)))
    , maxOutputSize(config->getIntOption("max_output_size", 2ULL << 30))
    , maxLogSize(config->getIntOption("max_log_size", 64ULL << 20))
    , uploadLogsToBinaryCache(config->getBoolOption("upload_logs_to_binary_cache", false))
@@ -177,29 +155,27 @@ void State::parseMachines(const std::string & contents)
        auto machine = std::make_shared<::Machine>(nix::Machine {
            // `storeUri`, not yet used
            "",
-            // `systemTypes`, not yet used
-            {},
+            // `systemTypes`
+            tokenizeString<StringSet>(tokens[1], ","),
            // `sshKey`
            tokens[2] == "-" ? "" : tokens[2],
            // `maxJobs`
            tokens[3] != ""
                ? string2Int<MaxJobs>(tokens[3]).value()
                : 1,
-            // `speedFactor`, not yet used
-            1,
+            // `speedFactor`
+            std::stof(tokens[4].c_str()),
            // `supportedFeatures`
            std::move(supportedFeatures),
            // `mandatoryFeatures`
            std::move(mandatoryFeatures),
            // `sshPublicHostKey`
            tokens[7] != "" && tokens[7] != "-"
-                ? base64Decode(tokens[7])
+                ? tokens[7]
                : "",
        });

        machine->sshName = tokens[0];
-        machine->systemTypesSet = tokenizeString<StringSet>(tokens[1], ",");
-        machine->speedFactorFloat = atof(tokens[4].c_str());

        /* Re-use the State object of the previous machine with the
           same name. */
@@ -663,7 +639,7 @@ void State::dumpStatus(Connection & conn)

                json machine = {
                    {"enabled",  m->enabled},
-                    {"systemTypes", m->systemTypesSet},
+                    {"systemTypes", m->systemTypes},
                    {"supportedFeatures", m->supportedFeatures},
                    {"mandatoryFeatures", m->mandatoryFeatures},
                    {"nrStepsDone", s->nrStepsDone.load()},
--- a/src/hydra-queue-runner/meson.build
+++ b/src/hydra-queue-runner/meson.build
@@ -0,0 +1,22 @@
+srcs = files(
+  'builder.cc',
+  'build-remote.cc',
+  'build-result.cc',
+  'dispatcher.cc',
+  'hydra-queue-runner.cc',
+  'nar-extractor.cc',
+  'queue-monitor.cc',
+)
+
+hydra_queue_runner = executable('hydra-queue-runner',
+  'hydra-queue-runner.cc',
+  srcs,
+  dependencies: [
+    libhydra_dep,
+    nix_dep,
+    pqxx_dep,
+    prom_cpp_core_dep,
+    prom_cpp_pull_dep,
+  ],
+  install: true,
+)
--- a/src/hydra-queue-runner/nar-extractor.cc
+++ b/src/hydra-queue-runner/nar-extractor.cc
@@ -6,7 +6,46 @@

 using namespace nix;

-struct Extractor : ParseSink
+
+struct NarMemberConstructor : CreateRegularFileSink
+{
+    NarMemberData & curMember;
+
+    HashSink hashSink = HashSink { HashAlgorithm::SHA256 };
+
+    std::optional<uint64_t> expectedSize;
+
+    NarMemberConstructor(NarMemberData & curMember)
+        : curMember(curMember)
+    { }
+
+    void isExecutable() override
+    {
+    }
+
+    void preallocateContents(uint64_t size) override
+    {
+        expectedSize = size;
+    }
+
+    void operator () (std::string_view data) override
+    {
+        assert(expectedSize);
+        *curMember.fileSize += data.size();
+        hashSink(data);
+        if (curMember.contents) {
+            curMember.contents->append(data);
+        }
+        assert(curMember.fileSize <= expectedSize);
+        if (curMember.fileSize == expectedSize) {
+            auto [hash, len] = hashSink.finish();
+            assert(curMember.fileSize == len);
+            curMember.sha256 = hash;
+        }
+    }
+};
+
+struct Extractor : FileSystemObjectSink
 {
    std::unordered_set<Path> filesToKeep {
        "/nix-support/hydra-build-products",
@@ -15,65 +54,41 @@ struct Extractor : ParseSink
    };

    NarMemberDatas & members;
-    NarMemberData * curMember = nullptr;
-    Path prefix;
+    std::filesystem::path prefix;
+
+    Path toKey(const CanonPath & path)
+    {
+        std::filesystem::path p = prefix;
+        // Conditional to avoid trailing slash
+        if (!path.isRoot()) p /= path.rel();
+        return p;
+    }

    Extractor(NarMemberDatas & members, const Path & prefix)
        : members(members), prefix(prefix)
    { }

-    void createDirectory(const Path & path) override
+    void createDirectory(const CanonPath & path) override
    {
-        members.insert_or_assign(prefix + path, NarMemberData { .type = SourceAccessor::Type::tDirectory });
+        members.insert_or_assign(toKey(path), NarMemberData { .type = SourceAccessor::Type::tDirectory });
    }

-    void createRegularFile(const Path & path) override
+    void createRegularFile(const CanonPath & path, std::function<void(CreateRegularFileSink &)> func) override
    {
-        curMember = &members.insert_or_assign(prefix + path, NarMemberData {
-            .type = SourceAccessor::Type::tRegular,
-            .fileSize = 0,
-            .contents = filesToKeep.count(path) ? std::optional("") : std::nullopt,
-        }).first->second;
+        NarMemberConstructor nmc {
+            members.insert_or_assign(toKey(path), NarMemberData {
+                .type = SourceAccessor::Type::tRegular,
+                .fileSize = 0,
+                .contents = filesToKeep.count(path.abs()) ? std::optional("") : std::nullopt,
+            }).first->second,
+        };
+        func(nmc);
    }

-    std::optional<uint64_t> expectedSize;
-    std::unique_ptr<HashSink> hashSink;
-
-    void preallocateContents(uint64_t size) override
+    void createSymlink(const CanonPath & path, const std::string & target) override
    {
-        expectedSize = size;
-        hashSink = std::make_unique<HashSink>(htSHA256);
+        members.insert_or_assign(toKey(path), NarMemberData { .type = SourceAccessor::Type::tSymlink });
    }
-
-    void receiveContents(std::string_view data) override
-    {
-        assert(expectedSize);
-        assert(curMember);
-        assert(hashSink);
-        *curMember->fileSize += data.size();
-        (*hashSink)(data);
-        if (curMember->contents) {
-            curMember->contents->append(data);
-        }
-        assert(curMember->fileSize <= expectedSize);
-        if (curMember->fileSize == expectedSize) {
-            auto [hash, len] = hashSink->finish();
-            assert(curMember->fileSize == len);
-            curMember->sha256 = hash;
-            hashSink.reset();
-        }
-    }
-
-    void createSymlink(const Path & path, const std::string & target) override
-    {
-        members.insert_or_assign(prefix + path, NarMemberData { .type = SourceAccessor::Type::tSymlink });
-    }
-
-    void isExecutable() override
-    { }
-
-    void closeRegularFile() override
-    { }
 };


--- a/src/hydra-queue-runner/queue-monitor.cc
+++ b/src/hydra-queue-runner/queue-monitor.cc
@@ -1,7 +1,6 @@
 #include "state.hh"
 #include "hydra-build-result.hh"
 #include "globals.hh"
-#include "thread-pool.hh"

 #include <cstring>

@@ -38,21 +37,16 @@ void State::queueMonitorLoop(Connection & conn)

    auto destStore = getDestStore();

+    unsigned int lastBuildId = 0;
+
    bool quit = false;
    while (!quit) {
-        auto t_before_work = std::chrono::steady_clock::now();
-
        localStore->clearPathInfoCache();

-        bool done = getQueuedBuilds(conn, destStore);
+        bool done = getQueuedBuilds(conn, destStore, lastBuildId);

        if (buildOne && buildOneDone) quit = true;

-        auto t_after_work = std::chrono::steady_clock::now();
-
-        prom.queue_monitor_time_spent_running.Increment(
-            std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count());
-
        /* Sleep until we get notification from the database about an
           event. */
        if (done && !quit) {
@@ -62,10 +56,12 @@ void State::queueMonitorLoop(Connection & conn)
            conn.get_notifs();

        if (auto lowestId = buildsAdded.get()) {
+            lastBuildId = std::min(lastBuildId, static_cast<unsigned>(std::stoul(*lowestId) - 1));
            printMsg(lvlTalkative, "got notification: new builds added to the queue");
        }
        if (buildsRestarted.get()) {
            printMsg(lvlTalkative, "got notification: builds restarted");
+            lastBuildId = 0; // check all builds
        }
        if (buildsCancelled.get() || buildsDeleted.get() || buildsBumped.get()) {
            printMsg(lvlTalkative, "got notification: builds cancelled or bumped");
@@ -75,10 +71,6 @@ void State::queueMonitorLoop(Connection & conn)
            printMsg(lvlTalkative, "got notification: jobset shares changed");
            processJobsetSharesChange(conn);
        }
-
-        auto t_after_sleep = std::chrono::steady_clock::now();
-        prom.queue_monitor_time_spent_waiting.Increment(
-            std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count());
    }

    exit(0);
@@ -92,18 +84,20 @@ struct PreviousFailure : public std::exception {


 bool State::getQueuedBuilds(Connection & conn,
-    ref<Store> destStore)
+    ref<Store> destStore, unsigned int & lastBuildId)
 {
    prom.queue_checks_started.Increment();

-    printInfo("checking the queue for builds...");
+    printInfo("checking the queue for builds > %d...", lastBuildId);

    /* Grab the queued builds from the database, but don't process
       them yet (since we don't want a long-running transaction). */
    std::vector<BuildID> newIDs;
-    std::unordered_map<BuildID, Build::ptr> newBuildsByID;
+    std::map<BuildID, Build::ptr> newBuildsByID;
    std::multimap<StorePath, BuildID> newBuildsByPath;

+    unsigned int newLastBuildId = lastBuildId;
+
    {
        pqxx::work txn(conn);

@@ -112,12 +106,17 @@ bool State::getQueuedBuilds(Connection & conn,
             "jobsets.name as jobset, job, drvPath, maxsilent, timeout, timestamp, "
             "globalPriority, priority from Builds "
             "inner join jobsets on builds.jobset_id = jobsets.id "
-             "where finished = 0 order by globalPriority desc, random()");
+             "where builds.id > $1 and finished = 0 order by globalPriority desc, builds.id",
+            lastBuildId);

        for (auto const & row : res) {
            auto builds_(builds.lock());
            BuildID id = row["id"].as<BuildID>();
            if (buildOne && id != buildOne) continue;
+            if (id > newLastBuildId) {
+                newLastBuildId = id;
+                prom.queue_max_id.Set(id);
+            }
            if (builds_->count(id)) continue;

            auto build = std::make_shared<Build>(
@@ -299,7 +298,7 @@ bool State::getQueuedBuilds(Connection & conn,
        try {
            createBuild(build);
        } catch (Error & e) {
-            e.addTrace({}, hintfmt("while loading build %d: ", build->id));
+            e.addTrace({}, HintFmt("while loading build %d: ", build->id));
            throw;
        }

@@ -319,13 +318,15 @@ bool State::getQueuedBuilds(Connection & conn,

        /* Stop after a certain time to allow priority bumps to be
           processed. */
-        if (std::chrono::system_clock::now() > start + std::chrono::seconds(60)) {
+        if (std::chrono::system_clock::now() > start + std::chrono::seconds(600)) {
            prom.queue_checks_early_exits.Increment();
            break;
        }
    }

    prom.queue_checks_finished.Increment();
+
+    lastBuildId = newBuildsByID.empty() ? newLastBuildId : newBuildsByID.begin()->first - 1;
    return newBuildsByID.empty();
 }

@@ -404,34 +405,6 @@ void State::processQueueChange(Connection & conn)
 }


-std::map<DrvOutput, std::optional<StorePath>> State::getMissingRemotePaths(
-    ref<Store> destStore,
-    const std::map<DrvOutput, std::optional<StorePath>> & paths)
-{
-    Sync<std::map<DrvOutput, std::optional<StorePath>>> missing_;
-    ThreadPool tp;
-
-    for (auto & [output, maybeOutputPath] : paths) {
-        if (!maybeOutputPath) {
-            auto missing(missing_.lock());
-            missing->insert({output, maybeOutputPath});
-        } else {
-            tp.enqueue([&] {
-                if (!destStore->isValidPath(*maybeOutputPath)) {
-                    auto missing(missing_.lock());
-                    missing->insert({output, maybeOutputPath});
-                }
-            });
-        }
-    }
-
-    tp.process();
-
-    auto missing(missing_.lock());
-    return *missing;
-}
-
-
 Step::ptr State::createStep(ref<Store> destStore,
    Connection & conn, Build::ptr build, const StorePath & drvPath,
    Build::ptr referringBuild, Step::ptr referringStep, std::set<StorePath> & finishedDrvs,
@@ -512,15 +485,16 @@ Step::ptr State::createStep(ref<Store> destStore,

    /* Are all outputs valid? */
    auto outputHashes = staticOutputHashes(*localStore, *(step->drv));
-    std::map<DrvOutput, std::optional<StorePath>> paths;
+    bool valid = true;
+    std::map<DrvOutput, std::optional<StorePath>> missing;
    for (auto & [outputName, maybeOutputPath] : destStore->queryPartialDerivationOutputMap(drvPath, &*localStore)) {
        auto outputHash = outputHashes.at(outputName);
-        paths.insert({{outputHash, outputName}, maybeOutputPath});
+        if (maybeOutputPath && destStore->isValidPath(*maybeOutputPath))
+            continue;
+        valid = false;
+        missing.insert({{outputHash, outputName}, maybeOutputPath});
    }

-    auto missing = getMissingRemotePaths(destStore, paths);
-    bool valid = missing.empty();
-
    /* Try to copy the missing paths from the local store or from
       substitutes. */
    if (!missing.empty()) {
@@ -726,7 +700,7 @@ BuildOutput State::getBuildOutputCached(Connection & conn, nix::ref<nix::Store>
                product.fileSize = row[2].as<off_t>();
            }
            if (!row[3].is_null())
-                product.sha256hash = Hash::parseAny(row[3].as<std::string>(), htSHA256);
+                product.sha256hash = Hash::parseAny(row[3].as<std::string>(), HashAlgorithm::SHA256);
            if (!row[4].is_null())
                product.path = row[4].as<std::string>();
            product.name = row[5].as<std::string>();
--- a/src/hydra-queue-runner/state.hh
+++ b/src/hydra-queue-runner/state.hh
@@ -7,7 +7,6 @@
 #include <memory>
 #include <queue>
 #include <regex>
-#include <semaphore>

 #include <prometheus/counter.h>
 #include <prometheus/gauge.h>
@@ -23,6 +22,8 @@
 #include "sync.hh"
 #include "nar-extractor.hh"
 #include "serve-protocol.hh"
+#include "serve-protocol-impl.hh"
+#include "serve-protocol-connection.hh"
 #include "machines.hh"


@@ -57,7 +58,6 @@ typedef enum {
    ssConnecting = 10,
    ssSendingInputs = 20,
    ssBuilding = 30,
-    ssWaitingForLocalSlot = 35,
    ssReceivingOutputs = 40,
    ssPostProcessing = 50,
 } StepState;
@@ -245,14 +245,6 @@ struct Machine : nix::Machine
       we are not yet used to, but once we are, we don't need this. */
    std::string sshName;

-    /* TODO Get rid once `nix::Machine::systemTypes` is a set not
-       vector. */
-    std::set<std::string> systemTypesSet;
-
-    /* TODO Get rid once `nix::Machine::systemTypes` is a `float` not
-       an `int`. */
-    float speedFactorFloat = 1.0;
-
    struct State {
        typedef std::shared_ptr<State> ptr;
        counter currentJobs{0};
@@ -279,7 +271,7 @@ struct Machine : nix::Machine
    {
        /* Check that this machine is of the type required by the
           step. */
-        if (!systemTypesSet.count(step->drv->platform == "builtin" ? nix::settings.thisSystem : step->drv->platform))
+        if (!systemTypes.count(step->drv->platform == "builtin" ? nix::settings.thisSystem : step->drv->platform))
            return false;

        /* Check that the step requires all mandatory features of this
@@ -309,29 +301,9 @@ struct Machine : nix::Machine
    }

    // A connection to a machine
-    struct Connection {
-        nix::FdSource from;
-        nix::FdSink to;
-        nix::ServeProto::Version remoteVersion;
-
+    struct Connection : nix::ServeProto::BasicClientConnection {
        // Backpointer to the machine
        ptr machine;
-
-        operator nix::ServeProto::ReadConn ()
-        {
-            return {
-                .from = from,
-                .version = remoteVersion,
-            };
-        }
-
-        operator nix::ServeProto::WriteConn ()
-        {
-            return {
-                .to = to,
-                .version = remoteVersion,
-            };
-        }
    };
 };

@@ -389,10 +361,6 @@ private:
    typedef std::map<std::string, Machine::ptr> Machines;
    nix::Sync<Machines> machines; // FIXME: use atomic_shared_ptr

-    /* Throttler for CPU-bound local work. */
-    static constexpr unsigned int maxSupportedLocalWorkers = 1024;
-    std::counting_semaphore<maxSupportedLocalWorkers> localWorkThrottler;
-
    /* Various stats. */
    time_t startedAt;
    counter nrBuildsRead{0};
@@ -470,7 +438,7 @@ private:

    /* How often the build steps of a jobset should be repeated in
       order to detect non-determinism. */
-    std::map<std::pair<std::string, std::string>, unsigned int> jobsetRepeats;
+    std::map<std::pair<std::string, std::string>, size_t> jobsetRepeats;

    bool uploadLogsToBinaryCache;

@@ -490,12 +458,7 @@ private:
        prometheus::Counter& queue_steps_created;
        prometheus::Counter& queue_checks_early_exits;
        prometheus::Counter& queue_checks_finished;
-
-        prometheus::Counter& dispatcher_time_spent_running;
-        prometheus::Counter& dispatcher_time_spent_waiting;
-
-        prometheus::Counter& queue_monitor_time_spent_running;
-        prometheus::Counter& queue_monitor_time_spent_waiting;
+        prometheus::Gauge& queue_max_id;

        PromMetrics();
    };
@@ -504,12 +467,6 @@ private:
 public:
    State(std::optional<std::string> metricsAddrOpt);

-    struct BuildOptions {
-        unsigned int maxSilentTime, buildTimeout, repeats;
-        size_t maxLogSize;
-        bool enforceDeterminism;
-    };
-
 private:

    nix::MaintainCount<counter> startDbUpdate();
@@ -545,7 +502,8 @@ private:
    void queueMonitorLoop(Connection & conn);

    /* Check the queue for new builds. */
-    bool getQueuedBuilds(Connection & conn, nix::ref<nix::Store> destStore);
+    bool getQueuedBuilds(Connection & conn,
+        nix::ref<nix::Store> destStore, unsigned int & lastBuildId);

    /* Handle cancellation, deletion and priority bumps. */
    void processQueueChange(Connection & conn);
@@ -553,12 +511,6 @@ private:
    BuildOutput getBuildOutputCached(Connection & conn, nix::ref<nix::Store> destStore,
        const nix::StorePath & drvPath);

-    /* Returns paths missing from the remote store. Paths are processed in
-     * parallel to work around the possible latency of remote stores. */
-    std::map<nix::DrvOutput, std::optional<nix::StorePath>> getMissingRemotePaths(
-        nix::ref<nix::Store> destStore,
-        const std::map<nix::DrvOutput, std::optional<nix::StorePath>> & paths);
-
    Step::ptr createStep(nix::ref<nix::Store> store,
        Connection & conn, Build::ptr build, const nix::StorePath & drvPath,
        Build::ptr referringBuild, Step::ptr referringStep, std::set<nix::StorePath> & finishedDrvs,
@@ -594,13 +546,12 @@ private:
       retried. */
    enum StepResult { sDone, sRetry, sMaybeCancelled };
    StepResult doBuildStep(nix::ref<nix::Store> destStore,
-        MachineReservation::ptr & reservation,
+        MachineReservation::ptr reservation,
        std::shared_ptr<ActiveStep> activeStep);

    void buildRemote(nix::ref<nix::Store> destStore,
-        MachineReservation::ptr & reservation,
        Machine::ptr machine, Step::ptr step,
-        const BuildOptions & buildOptions,
+        const nix::ServeProto::BuildOptions & buildOptions,
        RemoteResult & result, std::shared_ptr<ActiveStep> activeStep,
        std::function<void(StepState)> updateStep,
        NarMemberDatas & narMembers);
--- a/src/lib/Hydra/Base/Controller/NixChannel.pm
+++ b/src/lib/Hydra/Base/Controller/NixChannel.pm
@@ -4,7 +4,6 @@ use strict;
 use warnings;
 use base 'Hydra::Base::Controller::REST';
 use List::SomeUtils qw(any);
-use Nix::Store;
 use Hydra::Helper::Nix;
 use Hydra::Helper::CatalystUtils;

@@ -30,7 +29,7 @@ sub getChannelData {
        my $outputs = {};
        foreach my $output (@outputs) {
            my $outPath = $output->get_column("outpath");
-            next if $checkValidity && !isValidPath($outPath);
+            next if $checkValidity && !$MACHINE_LOCAL_STORE->isValidPath($outPath);
            $outputs->{$output->get_column("outname")} = $outPath;
            push @storePaths, $outPath;
            # Put the system type in the manifest (for top-level
--- a/src/lib/Hydra/Controller/API.pm
+++ b/src/lib/Hydra/Controller/API.pm
@@ -292,6 +292,23 @@ sub push_github : Chained('api') PathPart('push-github') Args(0) {
    $c->response->body("");
 }

+sub push_gitea : Chained('api') PathPart('push-gitea') Args(0) {
+    my ($self, $c) = @_;
+
+    $c->{stash}->{json}->{jobsetsTriggered} = [];
+
+    my $in = $c->request->{data};
+    my $url = $in->{repository}->{clone_url} or die;
+    $url =~ s/.git$//;
+    print STDERR "got push from Gitea repository $url\n";
+
+    triggerJobset($self, $c, $_, 0) foreach $c->model('DB::Jobsets')->search(
+        { 'project.enabled' => 1, 'me.enabled' => 1 },
+        { join => 'project'
+        , where => \ [ 'me.flake like ? or exists (select 1 from JobsetInputAlts where project = me.project and jobset = me.name and value like ?)', [ 'flake', "%$url%"], [ 'value', "%$url%" ] ]
+        });
+    $c->response->body("");
+}


 1;
--- a/src/lib/Hydra/Controller/Build.pm
+++ b/src/lib/Hydra/Controller/Build.pm
@@ -10,8 +10,6 @@ use File::Basename;
 use File::LibMagic;
 use File::stat;
 use Data::Dump qw(dump);
-use Nix::Store;
-use Nix::Config;
 use List::SomeUtils qw(all);
 use Encode;
 use JSON::PP;
@@ -83,9 +81,9 @@ sub build_GET {
    # false because `$_->path` will be empty
    $c->stash->{available} =
        $c->stash->{isLocalStore}
-        ? all { $_->path && isValidPath($_->path) } $build->buildoutputs->all
+        ? all { $_->path && $MACHINE_LOCAL_STORE->isValidPath($_->path) } $build->buildoutputs->all
        : 1;
-    $c->stash->{drvAvailable} = isValidPath $build->drvpath;
+    $c->stash->{drvAvailable} = $MACHINE_LOCAL_STORE->isValidPath($build->drvpath);

    if ($build->finished && $build->iscachedbuild) {
        my $path = ($build->buildoutputs)[0]->path or undef;
@@ -312,7 +310,7 @@ sub output : Chained('buildChain') PathPart Args(1) {
    error($c, "This build is not finished yet.") unless $build->finished;
    my $output = $build->buildoutputs->find({name => $outputName});
    notFound($c, "This build has no output named ‘$outputName’") unless defined $output;
-    gone($c, "Output is no longer available.") unless isValidPath $output->path;
+    gone($c, "Output is no longer available.") unless $MACHINE_LOCAL_STORE->isValidPath($output->path);

    $c->response->header('Content-Disposition', "attachment; filename=\"build-${\$build->id}-${\$outputName}.nar.bz2\"");
    $c->stash->{current_view} = 'NixNAR';
@@ -429,7 +427,7 @@ sub getDependencyGraph {
            };
        $$done{$path} = $node;
        my @refs;
-        foreach my $ref (queryReferences($path)) {
+        foreach my $ref ($MACHINE_LOCAL_STORE->queryReferences($path)) {
            next if $ref eq $path;
            next unless $runtime || $ref =~ /\.drv$/;
            getDependencyGraph($self, $c, $runtime, $done, $ref);
@@ -437,7 +435,7 @@ sub getDependencyGraph {
        }
        # Show in reverse topological order to flatten the graph.
        # Should probably do a proper BFS.
-        my @sorted = reverse topoSortPaths(@refs);
+        my @sorted = reverse $MACHINE_LOCAL_STORE->topoSortPaths(@refs);
        $node->{refs} = [map { $$done{$_} } @sorted];
    }

@@ -450,7 +448,7 @@ sub build_deps : Chained('buildChain') PathPart('build-deps') {
    my $build = $c->stash->{build};
    my $drvPath = $build->drvpath;

-    error($c, "Derivation no longer available.") unless isValidPath $drvPath;
+    error($c, "Derivation no longer available.") unless $MACHINE_LOCAL_STORE->isValidPath($drvPath);

    $c->stash->{buildTimeGraph} = getDependencyGraph($self, $c, 0, {}, $drvPath);

@@ -465,7 +463,7 @@ sub runtime_deps : Chained('buildChain') PathPart('runtime-deps') {

    requireLocalStore($c);

-    error($c, "Build outputs no longer available.") unless all { isValidPath($_) } @outPaths;
+    error($c, "Build outputs no longer available.") unless all { $MACHINE_LOCAL_STORE->isValidPath($_) } @outPaths;

    my $done = {};
    $c->stash->{runtimeGraph} = [ map { getDependencyGraph($self, $c, 1, $done, $_) } @outPaths ];
@@ -485,7 +483,7 @@ sub nix : Chained('buildChain') PathPart('nix') CaptureArgs(0) {
    if (isLocalStore) {
        foreach my $out ($build->buildoutputs) {
            notFound($c, "Path " . $out->path . " is no longer available.")
-                unless isValidPath($out->path);
+                unless $MACHINE_LOCAL_STORE->isValidPath($out->path);
        }
    }

--- a/src/lib/Hydra/Controller/Jobset.pm
+++ b/src/lib/Hydra/Controller/Jobset.pm
@@ -364,21 +364,6 @@ sub evals_GET {
    );
 }

-sub errors :Chained('jobsetChain') :PathPart('errors') :Args(0) :ActionClass('REST') { }
-
-sub errors_GET {
-    my ($self, $c) = @_;
-
-    $c->stash->{template} = 'eval-error.tt';
-
-    my $jobsetName = $c->stash->{params}->{name};
-    $c->stash->{jobset} = $c->stash->{project}->jobsets->find(
-        { name => $jobsetName },
-        { '+columns' => { 'errormsg' => 'errormsg' } }
-    );
-
-    $self->status_ok($c, entity => $c->stash->{jobset});
-}

 # Redirect to the latest finished evaluation of this jobset.
 sub latest_eval : Chained('jobsetChain') PathPart('latest-eval') {
--- a/src/lib/Hydra/Controller/JobsetEval.pm
+++ b/src/lib/Hydra/Controller/JobsetEval.pm
@@ -86,17 +86,6 @@ sub view_GET {
    );
 }

-sub errors :Chained('evalChain') :PathPart('errors') :Args(0) :ActionClass('REST') { }
-
-sub errors_GET {
-    my ($self, $c) = @_;
-
-    $c->stash->{template} = 'eval-error.tt';
-
-    $c->stash->{eval} = $c->model('DB::JobsetEvals')->find($c->stash->{eval}->id, { prefetch => 'evaluationerror' });
-
-    $self->status_ok($c, entity => $c->stash->{eval});
-}

 sub create_jobset : Chained('evalChain') PathPart('create-jobset') Args(0) {
    my ($self, $c) = @_;
--- a/src/lib/Hydra/Controller/Root.pm
+++ b/src/lib/Hydra/Controller/Root.pm
@@ -35,6 +35,7 @@ sub noLoginNeeded {

  return $whitelisted ||
         $c->request->path eq "api/push-github" ||
+         $c->request->path eq "api/push-gitea" ||
         $c->request->path eq "google-login" ||
         $c->request->path eq "github-redirect" ||
         $c->request->path eq "github-login" ||
@@ -80,7 +81,7 @@ sub begin :Private {
    $_->supportedInputTypes($c->stash->{inputTypes}) foreach @{$c->hydra_plugins};

    # XSRF protection: require POST requests to have the same origin.
-    if ($c->req->method eq "POST" && $c->req->path ne "api/push-github") {
+    if ($c->req->method eq "POST" && $c->req->path ne "api/push-github" && $c->req->path ne "api/push-gitea") {
        my $referer = $c->req->header('Referer');
        $referer //= $c->req->header('Origin');
        my $base = $c->req->base;
@@ -160,7 +161,7 @@ sub status_GET {
            { "buildsteps.busy" => { '!=', 0 } },
            { order_by => ["globalpriority DESC", "id"],
              join => "buildsteps",
-              columns => [@buildListColumns, 'buildsteps.drvpath', 'buildsteps.type']
+              columns => [@buildListColumns]
            })]
    );
 }
@@ -329,7 +330,7 @@ sub nar :Local :Args(1) {
    else {
        $path = $Nix::Config::storeDir . "/$path";

-        gone($c, "Path " . $path . " is no longer available.") unless isValidPath($path);
+        gone($c, "Path " . $path . " is no longer available.") unless $MACHINE_LOCAL_STORE->isValidPath($path);

        $c->stash->{current_view} = 'NixNAR';
        $c->stash->{storePath} = $path;
@@ -367,7 +368,7 @@ sub realisations :Path('realisations') :Args(StrMatch[REALISATIONS_REGEX]) {

    else {
        my ($rawDrvOutput) = $realisation =~ REALISATIONS_REGEX;
-        my $rawRealisation = queryRawRealisation($rawDrvOutput);
+        my $rawRealisation = $MACHINE_LOCAL_STORE->queryRawRealisation($rawDrvOutput);

        if (!$rawRealisation) {
            $c->response->status(404);
@@ -396,7 +397,7 @@ sub narinfo :Path :Args(StrMatch[NARINFO_REGEX]) {
        my ($hash) = $narinfo =~ NARINFO_REGEX;

        die("Hash length was not 32") if length($hash) != 32;
-        my $path = queryPathFromHashPart($hash);
+        my $path = $MACHINE_LOCAL_STORE->queryPathFromHashPart($hash);

        if (!$path) {
            $c->response->status(404);
--- a/src/lib/Hydra/Helper/BuildDiff.pm
+++ b/src/lib/Hydra/Helper/BuildDiff.pm
@@ -37,16 +37,7 @@ sub buildDiff {

    my $n = 0;
    foreach my $build (@{$builds}) {
-        my $aborted = $build->finished != 0 && (
-            # aborted
-            $build->buildstatus == 3
-            # cancelled
-            || $build->buildstatus == 4
-            # timeout
-            || $build->buildstatus == 7
-            # log limit exceeded
-            || $build->buildstatus == 10
-        );
+        my $aborted = $build->finished != 0 && ($build->buildstatus == 3 || $build->buildstatus == 4);
        my $d;
        my $found = 0;
        while ($n < scalar(@{$builds2})) {
@@ -88,4 +79,4 @@ sub buildDiff {
    return $ret;
 }

-1;
+1;
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@@ -40,8 +40,11 @@ our @EXPORT = qw(
    registerRoot
    restartBuilds
    run
+    $MACHINE_LOCAL_STORE
    );

+our $MACHINE_LOCAL_STORE = Nix::Store->new();
+

 sub getHydraHome {
    my $dir = $ENV{"HYDRA_HOME"} or die "The HYDRA_HOME directory does not exist!\n";
@@ -171,6 +174,9 @@ sub getDrvLogPath {
    for ($fn . $bucketed, $fn . $bucketed . ".bz2") {
        return $_ if -f $_;
    }
+    for ($fn . $bucketed, $fn . $bucketed . ".zst") {
+        return $_ if -f $_;
+    }
    return undef;
 }

@@ -187,6 +193,10 @@ sub findLog {

    return undef if scalar @outPaths == 0;

+    # Filter out any NULLs. Content-addressed derivations
+    # that haven't built yet or failed to build may have a NULL outPath.
+    @outPaths = grep {defined} @outPaths;
+
    my @steps = $c->model('DB::BuildSteps')->search(
        { path => { -in => [@outPaths] } },
        { select => ["drvpath"]
@@ -286,7 +296,8 @@ sub getEvals {

    my @evals = $evals_result_set->search(
        { hasnewbuilds => 1 },
-        { order_by => "$me.id DESC", rows => $rows, offset => $offset });
+        { order_by => "$me.id DESC", rows => $rows, offset => $offset
+        , prefetch => { evaluationerror => [ ] } });
    my @res = ();
    my $cache = {};

@@ -493,7 +504,7 @@ sub restartBuilds {
    $builds = $builds->search({ finished => 1 });

    foreach my $build ($builds->search({}, { columns => ["drvpath"] })) {
-        next if !isValidPath($build->drvpath);
+        next if !$MACHINE_LOCAL_STORE->isValidPath($build->drvpath);
        registerRoot $build->drvpath;
    }

--- a/src/lib/Hydra/Plugin/BazaarInput.pm
+++ b/src/lib/Hydra/Plugin/BazaarInput.pm
@@ -7,7 +7,6 @@ use Digest::SHA qw(sha256_hex);
 use File::Path;
 use Hydra::Helper::Exec;
 use Hydra::Helper::Nix;
-use Nix::Store;

 sub supportedInputTypes {
    my ($self, $inputTypes) = @_;
@@ -38,9 +37,9 @@ sub fetchInput {
    (my $cachedInput) = $self->{db}->resultset('CachedBazaarInputs')->search(
        {uri => $uri, revision => $revision});

-    addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;

-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
        $storePath = $cachedInput->storepath;
        $sha256 = $cachedInput->sha256hash;
    } else {
@@ -58,7 +57,7 @@ sub fetchInput {
        ($sha256, $storePath) = split ' ', $stdout;

        # FIXME: time window between nix-prefetch-bzr and addTempRoot.
-        addTempRoot($storePath);
+        $MACHINE_LOCAL_STORE->addTempRoot($storePath);

        $self->{db}->txn_do(sub {
            $self->{db}->resultset('CachedBazaarInputs')->create(
--- a/src/lib/Hydra/Plugin/CompressLog.pm
+++ b/src/lib/Hydra/Plugin/CompressLog.pm
@@ -9,11 +9,24 @@ use Hydra::Helper::CatalystUtils;
 sub stepFinished {
    my ($self, $step, $logPath) = @_;

-    my $doCompress = $self->{config}->{'compress_build_logs'} // "1";
+    my $doCompress = $self->{config}->{'compress_build_logs'} // '1';
+    my $silent = $self->{config}->{'compress_build_logs_silent'} // '0';
+    my $compression = $self->{config}->{'compress_build_logs_compression'} // 'bzip2';

-    if ($doCompress eq "1" && -e $logPath) {
-        print STDERR "compressing ‘$logPath’...\n";
-        system("bzip2", "--force", $logPath);
+    if (not -e $logPath or $doCompress ne "1") {
+        return;
+    }
+
+    if ($silent ne '1') {
+        print STDERR "compressing '$logPath' with $compression...\n";
+    }
+
+    if ($compression eq 'bzip2') {
+        system('bzip2', '--force', $logPath);
+    } elsif ($compression eq 'zstd') {
+        system('zstd', '--rm', '--quiet', '-T0', $logPath);
+    } else {
+        print STDERR "unknown compression type '$compression'\n";
    }
 }

--- a/src/lib/Hydra/Plugin/DarcsInput.pm
+++ b/src/lib/Hydra/Plugin/DarcsInput.pm
@@ -7,7 +7,6 @@ use Digest::SHA qw(sha256_hex);
 use File::Path;
 use Hydra::Helper::Exec;
 use Hydra::Helper::Nix;
-use Nix::Store;

 sub supportedInputTypes {
    my ($self, $inputTypes) = @_;
@@ -58,7 +57,7 @@ sub fetchInput {
        {uri => $uri, revision => $revision},
        {rows => 1});

-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
        $storePath = $cachedInput->storepath;
        $sha256 = $cachedInput->sha256hash;
        $revision = $cachedInput->revision;
@@ -75,8 +74,8 @@ sub fetchInput {
        die "darcs changes --count failed" if $? != 0;

        system "rm", "-rf", "$tmpDir/export/_darcs";
-        $storePath = addToStore("$tmpDir/export", 1, "sha256");
-        $sha256 = queryPathHash($storePath);
+        $storePath = $MACHINE_LOCAL_STORE->addToStore("$tmpDir/export", 1, "sha256");
+        $sha256 = $MACHINE_LOCAL_STORE->queryPathHash($storePath);
        $sha256 =~ s/sha256://;

        $self->{db}->txn_do(sub {
--- a/src/lib/Hydra/Plugin/GitInput.pm
+++ b/src/lib/Hydra/Plugin/GitInput.pm
@@ -186,9 +186,9 @@ sub fetchInput {
        {uri => $uri, branch => $branch, revision => $revision, isdeepclone => defined($deepClone) ? 1 : 0},
        {rows => 1});

-    addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;

-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
        $storePath = $cachedInput->storepath;
        $sha256 = $cachedInput->sha256hash;
        $revision = $cachedInput->revision;
@@ -217,7 +217,7 @@ sub fetchInput {
        ($sha256, $storePath) = split ' ', grab(cmd => ["nix-prefetch-git", $clonePath, $revision], chomp => 1);

        # FIXME: time window between nix-prefetch-git and addTempRoot.
-        addTempRoot($storePath);
+        $MACHINE_LOCAL_STORE->addTempRoot($storePath);

        $self->{db}->txn_do(sub {
            $self->{db}->resultset('CachedGitInputs')->update_or_create(
--- a/src/lib/Hydra/Plugin/GiteaStatus.pm
+++ b/src/lib/Hydra/Plugin/GiteaStatus.pm
@@ -88,10 +88,6 @@ sub buildQueued {
    common(@_, [], 0);
 }

-sub buildStarted {
-    common(@_, [], 1);
-}
-
 sub buildFinished {
    common(@_, 2);
 }
--- a/src/lib/Hydra/Plugin/MercurialInput.pm
+++ b/src/lib/Hydra/Plugin/MercurialInput.pm
@@ -7,7 +7,6 @@ use Digest::SHA qw(sha256_hex);
 use File::Path;
 use Hydra::Helper::Nix;
 use Hydra::Helper::Exec;
-use Nix::Store;
 use Fcntl qw(:flock);

 sub supportedInputTypes {
@@ -68,9 +67,9 @@ sub fetchInput {
    (my $cachedInput) = $self->{db}->resultset('CachedHgInputs')->search(
        {uri => $uri, branch => $branch, revision => $revision});

-    addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;

-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
        $storePath = $cachedInput->storepath;
        $sha256 = $cachedInput->sha256hash;
    } else {
@@ -85,7 +84,7 @@ sub fetchInput {
        ($sha256, $storePath) = split ' ', $stdout;

        # FIXME: time window between nix-prefetch-hg and addTempRoot.
-        addTempRoot($storePath);
+        $MACHINE_LOCAL_STORE->addTempRoot($storePath);

        $self->{db}->txn_do(sub {
            $self->{db}->resultset('CachedHgInputs')->update_or_create(
--- a/src/lib/Hydra/Plugin/PathInput.pm
+++ b/src/lib/Hydra/Plugin/PathInput.pm
@@ -5,7 +5,6 @@ use warnings;
 use parent 'Hydra::Plugin';
 use POSIX qw(strftime);
 use Hydra::Helper::Nix;
-use Nix::Store;

 sub supportedInputTypes {
    my ($self, $inputTypes) = @_;
@@ -30,7 +29,7 @@ sub fetchInput {
        {srcpath => $uri, lastseen => {">", $timestamp - $timeout}},
        {rows => 1, order_by => "lastseen DESC"});

-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
        $storePath = $cachedInput->storepath;
        $sha256 = $cachedInput->sha256hash;
        $timestamp = $cachedInput->timestamp;
@@ -46,7 +45,7 @@ sub fetchInput {
        }
        chomp $storePath;

-        $sha256 = (queryPathInfo($storePath, 0))[1] or die;
+        $sha256 = ($MACHINE_LOCAL_STORE->queryPathInfo($storePath, 0))[1] or die;

        ($cachedInput) = $self->{db}->resultset('CachedPathInputs')->search(
            {srcpath => $uri, sha256hash => $sha256});
--- a/src/lib/Hydra/Plugin/S3Backup.pm
+++ b/src/lib/Hydra/Plugin/S3Backup.pm
@@ -14,6 +14,7 @@ use Nix::Config;
 use Nix::Store;
 use Hydra::Model::DB;
 use Hydra::Helper::CatalystUtils;
+use Hydra::Helper::Nix;

 sub isEnabled {
    my ($self) = @_;
@@ -92,7 +93,7 @@ sub buildFinished {
        my $hash = substr basename($path), 0, 32;
        my ($deriver, $narHash, $time, $narSize, $refs) = queryPathInfo($path, 0);
        my $system;
-        if (defined $deriver and isValidPath($deriver)) {
+        if (defined $deriver and $MACHINE_LOCAL_STORE->isValidPath($deriver)) {
            $system = derivationFromPath($deriver)->{platform};
        }
        foreach my $reference (@{$refs}) {
--- a/src/lib/Hydra/Plugin/SubversionInput.pm
+++ b/src/lib/Hydra/Plugin/SubversionInput.pm
@@ -7,7 +7,6 @@ use Digest::SHA qw(sha256_hex);
 use Hydra::Helper::Exec;
 use Hydra::Helper::Nix;
 use IPC::Run;
-use Nix::Store;

 sub supportedInputTypes {
    my ($self, $inputTypes) = @_;
@@ -45,9 +44,9 @@ sub fetchInput {
    (my $cachedInput) = $self->{db}->resultset('CachedSubversionInputs')->search(
        {uri => $uri, revision => $revision});

-    addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;

-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
        $storePath = $cachedInput->storepath;
        $sha256 = $cachedInput->sha256hash;
    } else {
@@ -62,16 +61,16 @@ sub fetchInput {
        die "error checking out Subversion repo at `$uri':\n$stderr" if $res;

        if ($type eq "svn-checkout") {
-            $storePath = addToStore($wcPath, 1, "sha256");
+            $storePath = $MACHINE_LOCAL_STORE->addToStore($wcPath, 1, "sha256");
        } else {
            # Hm, if the Nix Perl bindings supported filters in
            # addToStore(), then we wouldn't need to make a copy here.
            my $tmpDir = File::Temp->newdir("hydra-svn-export.XXXXXX", CLEANUP => 1, TMPDIR => 1) or die;
            (system "svn", "export", $wcPath, "$tmpDir/source", "--quiet") == 0 or die "svn export failed";
-            $storePath = addToStore("$tmpDir/source", 1, "sha256");
+            $storePath = $MACHINE_LOCAL_STORE->addToStore("$tmpDir/source", 1, "sha256");
        }

-        $sha256 = queryPathHash($storePath); $sha256 =~ s/sha256://;
+        $sha256 = $MACHINE_LOCAL_STORE->queryPathHash($storePath); $sha256 =~ s/sha256://;

        $self->{db}->txn_do(sub {
            $self->{db}->resultset('CachedSubversionInputs')->update_or_create(
--- a/src/lib/Hydra/Schema/Result/EvaluationErrors.pm
+++ b/src/lib/Hydra/Schema/Result/EvaluationErrors.pm
@@ -105,6 +105,4 @@ __PACKAGE__->add_column(
    "+id" => { retrieve_on_insert => 1 }
 );

-__PACKAGE__->mk_group_accessors('column' => 'has_error');
-
 1;
--- a/src/lib/Hydra/Schema/Result/Jobsets.pm
+++ b/src/lib/Hydra/Schema/Result/Jobsets.pm
@@ -386,8 +386,6 @@ __PACKAGE__->add_column(
    "+id" => { retrieve_on_insert => 1 }
 );

-__PACKAGE__->mk_group_accessors('column' => 'has_error');
-
 sub supportsDynamicRunCommand {
  my ($self) = @_;

--- a/src/lib/Hydra/Schema/ResultSet/EvaluationErrors.pm
+++ b/src/lib/Hydra/Schema/ResultSet/EvaluationErrors.pm
@@ -1,30 +0,0 @@
-package Hydra::Schema::ResultSet::EvaluationErrors;
-
-use strict;
-use utf8;
-use warnings;
-
-use parent 'DBIx::Class::ResultSet';
-
-use Storable qw(dclone);
-
-__PACKAGE__->load_components('Helper::ResultSet::RemoveColumns');
-
-# Exclude expensive error message values unless explicitly requested, and
-# replace them with a summary field describing their presence/absence.
-sub search_rs {
-  my ( $class, $query, $attrs ) = @_;
-
-  if ($attrs) {
-    $attrs = dclone($attrs);
-  }
-
-  unless (exists $attrs->{'select'} || exists $attrs->{'columns'}) {
-    $attrs->{'+columns'}->{'has_error'} = "errormsg != ''";
-  }
-  unless (exists $attrs->{'+columns'}->{'errormsg'}) {
-    push @{ $attrs->{'remove_columns'} }, 'errormsg';
-  }
-
-  return $class->next::method($query, $attrs);
-}
--- a/src/lib/Hydra/Schema/ResultSet/Jobsets.pm
+++ b/src/lib/Hydra/Schema/ResultSet/Jobsets.pm
@@ -1,30 +0,0 @@
-package Hydra::Schema::ResultSet::Jobsets;
-
-use strict;
-use utf8;
-use warnings;
-
-use parent 'DBIx::Class::ResultSet';
-
-use Storable qw(dclone);
-
-__PACKAGE__->load_components('Helper::ResultSet::RemoveColumns');
-
-# Exclude expensive error message values unless explicitly requested, and
-# replace them with a summary field describing their presence/absence.
-sub search_rs {
-  my ( $class, $query, $attrs ) = @_;
-
-  if ($attrs) {
-    $attrs = dclone($attrs);
-  }
-
-  unless (exists $attrs->{'select'} || exists $attrs->{'columns'}) {
-    $attrs->{'+columns'}->{'has_error'} = "errormsg != ''";
-  }
-  unless (exists $attrs->{'+columns'}->{'errormsg'}) {
-    push @{ $attrs->{'remove_columns'} }, 'errormsg';
-  }
-
-  return $class->next::method($query, $attrs);
-}
--- a/src/lib/Hydra/View/NARInfo.pm
+++ b/src/lib/Hydra/View/NARInfo.pm
@@ -8,6 +8,7 @@ use MIME::Base64;
 use Nix::Manifest;
 use Nix::Store;
 use Nix::Utils;
+use Hydra::Helper::Nix;
 use base qw/Catalyst::View/;

 sub process {
@@ -17,7 +18,7 @@ sub process {

    $c->response->content_type('text/x-nix-narinfo'); # !!! check MIME type

-    my ($deriver, $narHash, $time, $narSize, $refs) = queryPathInfo($storePath, 1);
+    my ($deriver, $narHash, $time, $narSize, $refs) = $MACHINE_LOCAL_STORE->queryPathInfo($storePath, 1);

    my $info;
    $info .= "StorePath: $storePath\n";
@@ -28,8 +29,8 @@ sub process {
    $info .= "References: " . join(" ", map { basename $_ } @{$refs}) . "\n";
    if (defined $deriver) {
        $info .= "Deriver: " . basename $deriver . "\n";
-        if (isValidPath($deriver)) {
-            my $drv = derivationFromPath($deriver);
+        if ($MACHINE_LOCAL_STORE->isValidPath($deriver)) {
+            my $drv = $MACHINE_LOCAL_STORE->derivationFromPath($deriver);
            $info .= "System: $drv->{platform}\n";
        }
    }
--- a/src/lib/Hydra/View/NixLog.pm
+++ b/src/lib/Hydra/View/NixLog.pm
@@ -16,7 +16,10 @@ sub process {

    my $tail = int($c->stash->{tail} // "0");

-    if ($logPath =~ /\.bz2$/) {
+    if ($logPath =~ /\.zst$/) {
+        my $doTail = $tail ? "| tail -n '$tail'" : "";
+        open($fh, "-|", "zstd -dc < '$logPath' $doTail") or die;
+    } elsif ($logPath =~ /\.bz2$/) {
        my $doTail = $tail ? "| tail -n '$tail'" : "";
        open($fh, "-|", "bzip2 -dc < '$logPath' $doTail") or die;
    } else {
--- a/src/lib/Makefile.am
+++ b/src/lib/Makefile.am
@@ -1,22 +0,0 @@
-PERL_MODULES =					\
-  $(wildcard *.pm)				\
-  $(wildcard Hydra/*.pm)			\
-  $(wildcard Hydra/Helper/*.pm)			\
-  $(wildcard Hydra/Model/*.pm)			\
-  $(wildcard Hydra/View/*.pm)			\
-  $(wildcard Hydra/Schema/*.pm)			\
-  $(wildcard Hydra/Schema/Result/*.pm)			\
-  $(wildcard Hydra/Schema/ResultSet/*.pm)			\
-  $(wildcard Hydra/Controller/*.pm)		\
-  $(wildcard Hydra/Base/*.pm)			\
-  $(wildcard Hydra/Base/Controller/*.pm) 	\
-  $(wildcard Hydra/Script/*.pm)			\
-  $(wildcard Hydra/Component/*.pm)		\
-  $(wildcard Hydra/Event/*.pm)		\
-  $(wildcard Hydra/Plugin/*.pm)
-
-EXTRA_DIST = \
-  $(PERL_MODULES)
-
-hydradir = $(libexecdir)/hydra/lib
-nobase_hydra_DATA = $(PERL_MODULES)
--- a/src/libhydra/meson.build
+++ b/src/libhydra/meson.build
@@ -0,0 +1,5 @@
+libhydra_inc = include_directories('.')
+
+libhydra_dep = declare_dependency(
+  include_directories: [libhydra_inc],
+)
--- a/src/meson.build
+++ b/src/meson.build
@@ -0,0 +1,86 @@
+# Native code
+subdir('libhydra')
+subdir('hydra-eval-jobs')
+subdir('hydra-evaluator')
+subdir('hydra-queue-runner')
+
+hydra_libexecdir = get_option('libexecdir') / 'hydra'
+
+# Data and interpreted
+foreach dir : ['lib', 'root']
+  install_subdir(dir,
+    install_dir: hydra_libexecdir,
+  )
+endforeach
+subdir('sql')
+subdir('ttf')
+
+# Static files for website
+
+hydra_libexecdir_static = hydra_libexecdir / 'root' / 'static'
+
+## Bootstrap
+
+bootstrap_name = 'bootstrap-4.3.1-dist'
+bootstrap = custom_target(
+  'extract-bootstrap',
+  input: 'root' / (bootstrap_name + '.zip'),
+  output: bootstrap_name,
+  command: ['unzip', '-u', '-d', '@OUTDIR@', '@INPUT@'],
+)
+custom_target(
+  'name-bootstrap',
+  input: bootstrap,
+  output: 'bootstrap',
+  command: ['cp', '-r', '@INPUT@' , '@OUTPUT@'],
+  install: true,
+  install_dir: hydra_libexecdir_static,
+)
+
+## Flot
+
+custom_target(
+  'extract-flot',
+  input: 'root' / 'flot-0.8.3.zip',
+  output: 'flot',
+  command: ['unzip', '-u', '-d', '@OUTDIR@', '@INPUT@'],
+  install: true,
+  install_dir: hydra_libexecdir_static / 'js',
+)
+
+## Fontawesome
+
+fontawesome_name = 'fontawesome-free-5.10.2-web'
+fontawesome = custom_target(
+  'extract-fontawesome',
+  input: 'root' / (fontawesome_name + '.zip'),
+  output: fontawesome_name,
+  command: ['unzip', '-u', '-d', '@OUTDIR@', '@INPUT@'],
+)
+custom_target(
+  'name-fontawesome-css',
+  input: fontawesome,
+  output: 'css',
+  command: ['cp', '-r', '@INPUT@/css', '@OUTPUT@'],
+  install: true,
+  install_dir: hydra_libexecdir_static / 'fontawesome',
+)
+custom_target(
+  'name-fontawesome-webfonts',
+  input: fontawesome,
+  output: 'webfonts',
+  command: ['cp', '-r', '@INPUT@/webfonts', '@OUTPUT@'],
+  install: true,
+  install_dir: hydra_libexecdir_static / 'fontawesome',
+)
+
+# Scripts
+
+install_subdir('script',
+  install_dir: get_option('bindir'),
+  exclude_files: [
+    'hydra-dev-server',
+  ],
+  install_mode: 'rwxr-xr-x',
+  strip_directory: true,
+)
--- a/src/root/Makefile.am
+++ b/src/root/Makefile.am
@@ -1,39 +0,0 @@
-TEMPLATES = $(wildcard *.tt)
-STATIC = \
-  $(wildcard static/images/*) \
-  $(wildcard static/css/*) \
-  static/js/bootbox.min.js \
-  static/js/popper.min.js \
-  static/js/common.js \
-  static/js/jquery/jquery-3.4.1.min.js \
-  static/js/jquery/jquery-ui-1.10.4.min.js
-
-FLOT = flot-0.8.3.zip
-BOOTSTRAP = bootstrap-4.3.1-dist.zip
-FONTAWESOME = fontawesome-free-5.10.2-web.zip
-
-ZIPS = $(FLOT) $(BOOTSTRAP) $(FONTAWESOME)
-
-EXTRA_DIST = $(TEMPLATES) $(STATIC) $(ZIPS)
-
-hydradir = $(libexecdir)/hydra/root
-nobase_hydra_DATA = $(EXTRA_DIST)
-
-all:
-	mkdir -p $(srcdir)/static/js
-	unzip -u -d $(srcdir)/static $(BOOTSTRAP)
-	rm -rf $(srcdir)/static/bootstrap
-	mv $(srcdir)/static/$(basename $(BOOTSTRAP)) $(srcdir)/static/bootstrap
-	unzip -u -d $(srcdir)/static/js $(FLOT)
-	unzip -u -d $(srcdir)/static $(FONTAWESOME)
-	rm -rf $(srcdir)/static/fontawesome
-	mv $(srcdir)/static/$(basename $(FONTAWESOME)) $(srcdir)/static/fontawesome
-
-install-data-local: $(ZIPS)
-	mkdir -p $(hydradir)/static/js
-	cp -prvd $(srcdir)/static/js/* $(hydradir)/static/js
-	mkdir -p $(hydradir)/static/bootstrap
-	cp -prvd $(srcdir)/static/bootstrap/* $(hydradir)/static/bootstrap
-	mkdir -p $(hydradir)/static/fontawesome/{css,webfonts}
-	cp -prvd $(srcdir)/static/fontawesome/css/* $(hydradir)/static/fontawesome/css
-	cp -prvd $(srcdir)/static/fontawesome/webfonts/* $(hydradir)/static/fontawesome/webfonts
--- a/src/root/build.tt
+++ b/src/root/build.tt
@@ -61,7 +61,21 @@ END;
            <td>[% IF step.busy != 0 || ((step.machine || step.starttime) && (step.status == 0 || step.status == 1 || step.status == 3 || step.status == 4 || step.status == 7)); INCLUDE renderMachineName machine=step.machine; ELSE; "<em>n/a</em>"; END %]</td>
            <td class="step-status">
              [% IF step.busy != 0 %]
-                [% INCLUDE renderBusyStatus %]
+                [% IF step.busy == 1 %]
+                  <strong>Preparing</strong>
+                [% ELSIF step.busy == 10 %]
+                  <strong>Connecting</strong>
+                [% ELSIF step.busy == 20 %]
+                  <strong>Sending inputs</strong>
+                [% ELSIF step.busy == 30 %]
+                  <strong>Building</strong>
+                [% ELSIF step.busy == 40 %]
+                  <strong>Receiving outputs</strong>
+                [% ELSIF step.busy == 50 %]
+                  <strong>Post-processing</strong>
+                [% ELSE %]
+                  <strong>Unknown state</strong>
+                [% END %]
              [% ELSIF step.status == 0 %]
                [% IF step.isnondeterministic %]
                  <span class="warn">Succeeded with non-determistic result</span>
--- a/src/root/common.tt
+++ b/src/root/common.tt
@@ -91,17 +91,6 @@ BLOCK renderDuration;
  duration % 60 %]s[%
 END;

-BLOCK renderDrvInfo;
-  drvname = step.drvpath
-    .substr(11) # strip `/nix/store/`
-    .split('-').slice(1).join("-") # strip hash part
-    .substr(0, -4); # strip `.drv`
-  IF drvname != releasename;
-    IF step.type == 0; action = "Build"; ELSE; action = "Substitution"; END;
-    IF drvname; %]<em> ([% action %] of [% drvname %])</em>[% END;
-  END;
-END;
-

 BLOCK renderBuildListHeader %]
  <table class="table table-striped table-condensed clickable-rows">
@@ -142,12 +131,7 @@ BLOCK renderBuildListBody;
      [% END %]
      <td><a class="row-link" href="[% link %]">[% build.id %]</a></td>
      [% IF !hideJobName %]
-        <td>
-          <a href="[%link%]">[% IF !hideJobsetName %][%build.jobset.get_column("project")%]:[%build.jobset.get_column("name")%]:[% END %][%build.get_column("job")%]</a>
-          [% IF showStepName %]
-            [% INCLUDE renderDrvInfo step=build.buildsteps releasename=build.nixname %]
-          [% END %]
-        </td>
+        <td><a href="[%link%]">[% IF !hideJobsetName %][%build.jobset.get_column("project")%]:[%build.jobset.get_column("name")%]:[% END %][%build.get_column("job")%]</td>
      [% END %]
      <td class="nowrap">[% t = showSchedulingInfo ? build.timestamp : build.stoptime; IF t; INCLUDE renderRelativeDate timestamp=(showSchedulingInfo ? build.timestamp : build.stoptime); ELSE; "-"; END %]</td>
      <td>[% !showSchedulingInfo and build.get_column('releasename') ? build.get_column('releasename') : build.nixname %]</td>
@@ -261,27 +245,6 @@ BLOCK renderBuildStatusIcon;
 END;


-BLOCK renderBusyStatus;
-  IF step.busy == 1 %]
-    <strong>Preparing</strong>
-  [% ELSIF step.busy == 10 %]
-    <strong>Connecting</strong>
-  [% ELSIF step.busy == 20 %]
-    <strong>Sending inputs</strong>
-  [% ELSIF step.busy == 30 %]
-    <strong>Building</strong>
-  [% ELSIF step.busy == 35 %]
-    <strong>Waiting to receive outputs</strong>
-  [% ELSIF step.busy == 40 %]
-    <strong>Receiving outputs</strong>
-  [% ELSIF step.busy == 50 %]
-    <strong>Post-processing</strong>
-  [% ELSE %]
-    <strong>Unknown state</strong>
-  [% END;
-END;
-
-
 BLOCK renderStatus;
  IF build.finished;
    buildstatus = build.buildstatus;
@@ -411,7 +374,7 @@ BLOCK renderInputDiff; %]
              [% ELSIF bi1.uri == bi2.uri && bi1.revision != bi2.revision %]
                [% IF bi1.type == "git" %]
                  <tr><td>
-                    <b>[% bi1.name %]</b></td><td><tt>[% INCLUDE renderDiffUri contents=(bi1.revision.substr(0, 8) _ ' to ' _ bi2.revision.substr(0, 8)) %]</tt>
+                    <b>[% bi1.name %]</b></td><td><tt>[% INCLUDE renderDiffUri contents=(bi1.revision.substr(0, 12) _ ' to ' _ bi2.revision.substr(0, 12)) %]</tt>
                  </td></tr>
                [% ELSE %]
                  <tr><td>
@@ -513,7 +476,7 @@ BLOCK renderEvals %]
            ELSE %]
             -
            [% END %]
-            [% IF eval.evaluationerror.has_error %]
+            [% IF eval.evaluationerror.errormsg %]
              <span class="badge badge-warning">Eval Errors</span>
            [% END %]
          </td>
@@ -639,7 +602,7 @@ BLOCK renderJobsetOverview %]
        <td>[% HTML.escape(j.description) %]</td>
        <td>[% IF j.lastcheckedtime;
                 INCLUDE renderDateTime timestamp = j.lastcheckedtime;
-                 IF j.has_error || j.fetcherrormsg; %]&nbsp;<span class = 'badge badge-warning'>Error</span>[% END;
+                 IF j.errormsg || j.fetcherrormsg; %]&nbsp;<span class = 'badge badge-warning'>Error</span>[% END;
                 ELSE; "-";
               END %]</td>
        [% IF j.get_column('nrtotal') > 0 %]
--- a/src/root/eval-error.tt
+++ b/src/root/eval-error.tt
@@ -1,26 +0,0 @@
-[% PROCESS common.tt %]
-<!DOCTYPE html>
-
-<html lang="en">
-
-  <head>
-    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
-    <meta http-equiv="X-UA-Compatible" content="IE=Edge" />
-    [% INCLUDE style.tt %]
-  </head>
-
-  <body>
-
-    <div class="tab-content tab-pane">
-        <div id="tabs-errors" class="">
-          [% IF jobset %]
-              <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(jobset.errortime || jobset.lastcheckedtime) %].</p>
-              <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(jobset.fetcherrormsg || jobset.errormsg) %]</pre></div></div>
-          [% ELSIF eval %]
-              <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(eval.evaluationerror.errortime || eval.timestamp) %].</p>
-              <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(eval.evaluationerror.errormsg) %]</pre></div></div>
-          [% END %]
-        </div>
-    </div>
-  </body>
-</html>
--- a/src/root/job.tt
+++ b/src/root/job.tt
@@ -27,15 +27,15 @@ removed or had an evaluation error.</div>
 <div id="generic-tabs" class="tab-content">

  <div id="tabs-status" class="tab-pane active">
+    [% IF queuedBuilds.size != 0 %]
+      <h3>Queued builds</h3>
+      [% INCLUDE renderBuildList builds=queuedBuilds showSchedulingInfo=1 hideResultInfo=1 %]
+    [% END %]
    [% IF lastBuilds.size != 0 %]
      <h3>Latest builds</h3>
      [% INCLUDE renderBuildList builds=lastBuilds
          linkToAll=c.uri_for('/job' project.name jobset.name job 'all') %]
    [% END %]
-    [% IF queuedBuilds.size != 0 %]
-      <h3>Queued builds</h3>
-      [% INCLUDE renderBuildList builds=queuedBuilds showSchedulingInfo=1 hideResultInfo=1 %]
-    [% END %]
  </div>

  [% IF constituentJobs.size > 0 %]
--- a/src/root/jobset-eval.tt
+++ b/src/root/jobset-eval.tt
@@ -65,7 +65,7 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),
  [% END %]

  [% IF aborted.size > 0 %]
-    <li class="nav-item"><a class="nav-link" href="#tabs-aborted" data-toggle="tab"><span class="text-warning">Aborted / Timed out Jobs ([% aborted.size %])</span></a></li>
+    <li class="nav-item"><a class="nav-link" href="#tabs-aborted" data-toggle="tab"><span class="text-warning">Aborted Jobs ([% aborted.size %])</span></a></li>
  [% END %]
  [% IF nowFail.size > 0 %]
    <li class="nav-item"><a class="nav-link" href="#tabs-now-fail" data-toggle="tab"><span class="text-warning">Newly Failing Jobs ([% nowFail.size %])</span></a></li>
@@ -90,7 +90,7 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),
  [% END %]
  <li class="nav-item"><a class="nav-link" href="#tabs-inputs" data-toggle="tab">Inputs</a></li>

-  [% IF eval.evaluationerror.has_error %]
+  [% IF eval.evaluationerror.errormsg %]
    <li class="nav-item"><a class="nav-link" href="#tabs-errors" data-toggle="tab"><span class="text-warning">Evaluation Errors</span></a></li>
  [% END %]
 </ul>
@@ -108,6 +108,13 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),

 <div class="tab-content">

+  [% IF eval.evaluationerror.errormsg %]
+    <div id="tabs-errors" class="tab-pane">
+      <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(eval.evaluationerror.errortime || eval.timestamp) %].</p>
+      <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(eval.evaluationerror.errormsg) %]</pre></div></div>
+    </div>
+  [% END %]
+
  <div id="tabs-aborted" class="tab-pane">
    [% INCLUDE renderSome builds=aborted tabname="#tabs-aborted" %]
  </div>
@@ -165,9 +172,10 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),
    [% END %]
  </div>

-  [% IF eval.evaluationerror.has_error %]
+  [% IF eval.evaluationerror.errormsg %]
    <div id="tabs-errors" class="tab-pane">
-      <iframe src="[% c.uri_for(c.controller('JobsetEval').action_for('errors'), [eval.id], params) %]" loading="lazy" frameBorder="0" width="100%"></iframe>
+      <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(eval.evaluationerror.errortime || eval.timestamp) %].</p>
+      <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(eval.evaluationerror.errormsg) %]</pre></div></div>
    </div>
  [% END %]
 </div>
--- a/src/root/jobset.tt
+++ b/src/root/jobset.tt
@@ -61,7 +61,7 @@
  [% END %]

  <li class="nav-item"><a class="nav-link active" href="#tabs-evaluations" data-toggle="tab">Evaluations</a></li>
-  [% IF jobset.has_error || jobset.fetcherrormsg %]
+  [% IF jobset.errormsg || jobset.fetcherrormsg %]
    <li class="nav-item"><a class="nav-link" href="#tabs-errors" data-toggle="tab"><span class="text-warning">Evaluation Errors</span></a></li>
  [% END %]
  <li class="nav-item"><a class="nav-link" href="#tabs-jobs" data-toggle="tab">Jobs</a></li>
@@ -79,7 +79,7 @@
        <th>Last checked:</th>
        <td>
          [% IF jobset.lastcheckedtime %]
-            [% INCLUDE renderDateTime timestamp = jobset.lastcheckedtime %], [% IF jobset.has_error || jobset.fetcherrormsg %]<em class="text-warning">with errors!</em>[% ELSE %]<em>no errors</em>[% END %]
+            [% INCLUDE renderDateTime timestamp = jobset.lastcheckedtime %], [% IF jobset.errormsg || jobset.fetcherrormsg %]<em class="text-warning">with errors!</em>[% ELSE %]<em>no errors</em>[% END %]
          [% ELSE %]
            <em>never</em>
          [% END %]
@@ -117,9 +117,10 @@

  </div>

-  [% IF jobset.has_error || jobset.fetcherrormsg %]
+  [% IF jobset.errormsg || jobset.fetcherrormsg %]
    <div id="tabs-errors" class="tab-pane">
-      <iframe src="[% c.uri_for('/jobset' project.name jobset.name "errors") %]" loading="lazy" frameBorder="0" width="100%"></iframe>
+      <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(jobset.errortime || jobset.lastcheckedtime) %].</p>
+      <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(jobset.fetcherrormsg || jobset.errormsg) %]</pre></div></div>
    </div>
  [% END %]

--- a/src/root/layout.tt
+++ b/src/root/layout.tt
@@ -10,7 +10,31 @@

    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=Edge" />
-    [% INCLUDE style.tt %]
+
+    <script type="text/javascript" src="[% c.uri_for("/static/js/jquery/jquery-3.4.1.min.js") %]"></script>
+    <script type="text/javascript" src="[% c.uri_for("/static/js/jquery/jquery-ui-1.10.4.min.js") %]"></script>
+    <script type="text/javascript" src="[% c.uri_for("/static/js/moment/moment-2.24.0.min.js") %]"></script>
+
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+
+    <link href="[% c.uri_for("/static/fontawesome/css/all.css") %]" rel="stylesheet" />
+    <script type="text/javascript" src="[% c.uri_for("/static/js/popper.min.js") %]"></script>
+    <script type="text/javascript" src="[% c.uri_for("/static/bootstrap/js/bootstrap.min.js") %]"></script>
+    <link href="[% c.uri_for("/static/bootstrap/css/bootstrap.min.css") %]" rel="stylesheet" />
+
+    <!-- hydra.css may need to be moved to before boostrap to make the @media rule work. -->
+    <link rel="stylesheet" href="[% c.uri_for("/static/css/hydra.css") %]" type="text/css" />
+    <link rel="stylesheet" href="[% c.uri_for("/static/css/rotated-th.css") %]" type="text/css" />
+
+    <style>
+      .popover { max-width: 40%; }
+    </style>
+
+    <script type="text/javascript" src="[% c.uri_for("/static/js/bootbox.min.js") %]"></script>
+
+    <link rel="stylesheet" href="[% c.uri_for("/static/css/tree.css") %]" type="text/css" />
+
+    <script type="text/javascript" src="[% c.uri_for("/static/js/common.js") %]"></script>

    [% IF c.config.enable_google_login %]
      <meta name="google-signin-client_id" content="[% c.config.google_client_id %]">
--- a/src/root/machine-status.tt
+++ b/src/root/machine-status.tt
@@ -6,10 +6,10 @@
  <thead>
    <tr>
      <th>Job</th>
+      <th>System</th>
      <th>Build</th>
      <th>Step</th>
      <th>What</th>
-      <th>Status</th>
      <th>Since</th>
    </tr>
  </thead>
@@ -40,10 +40,10 @@
          [% idle = 0 %]
          <tr>
            <td><tt>[% INCLUDE renderFullJobName project=step.project jobset=step.jobset job=step.job %]</tt></td>
+            <td><tt>[% step.system %]</tt></td>
            <td><a href="[% c.uri_for('/build' step.build) %]">[% step.build %]</a></td>
            <td>[% IF step.busy >= 30 %]<a class="row-link" href="[% c.uri_for('/build' step.build 'nixlog' step.stepnr 'tail') %]">[% step.stepnr %]</a>[% ELSE; step.stepnr; END %]</td>
            <td><tt>[% step.drvpath.match('-(.*)').0 %]</tt></td>
-            <td>[% INCLUDE renderBusyStatus %]</td>
            <td style="width: 10em">[% INCLUDE renderDuration duration = curTime - step.starttime %] </td>
          </tr>
        [% END %]
--- a/src/root/reproduce.tt
+++ b/src/root/reproduce.tt
@@ -7,7 +7,7 @@ main() {

 set -e

-tmpDir=${TMPDIR:-/tmp}/build-[% build.id +%]
+tmpDir=$(realpath "${TMPDIR:-/tmp}")/build-[% build.id +%]
 declare -a args extraArgs


--- a/src/root/static/js/common.js
+++ b/src/root/static/js/common.js
@@ -129,12 +129,6 @@ $(document).ready(function() {
            el.addClass("is-local");
        }
    });
-
-    [...document.getElementsByTagName("iframe")].forEach((element) => {
-        element.contentWindow.addEventListener("DOMContentLoaded", (_) => {
-            element.style.height = element.contentWindow.document.body.scrollHeight + 'px';
-        })
-    })
 });

 var tabsLoaded = {};
--- a/src/root/status.tt
+++ b/src/root/status.tt
@@ -7,7 +7,7 @@

 [% ELSE %]

-  [% INCLUDE renderBuildList builds=resource showSchedulingInfo=1 hideResultInfo=1 busy=1 showStepName=1 %]
+  [% INCLUDE renderBuildList builds=resource showSchedulingInfo=1 hideResultInfo=1 busy=1 %]

 [% END %]

--- a/src/root/style.tt
+++ b/src/root/style.tt
@@ -1,24 +0,0 @@
-<script type="text/javascript" src="[% c.uri_for("/static/js/jquery/jquery-3.4.1.min.js") %]"></script>
-<script type="text/javascript" src="[% c.uri_for("/static/js/jquery/jquery-ui-1.10.4.min.js") %]"></script>
-<script type="text/javascript" src="[% c.uri_for("/static/js/moment/moment-2.24.0.min.js") %]"></script>
-
-<meta name="viewport" content="width=device-width, initial-scale=1.0" />
-
-<link href="[% c.uri_for("/static/fontawesome/css/all.css") %]" rel="stylesheet" />
-<script type="text/javascript" src="[% c.uri_for("/static/js/popper.min.js") %]"></script>
-<script type="text/javascript" src="[% c.uri_for("/static/bootstrap/js/bootstrap.min.js") %]"></script>
-<link href="[% c.uri_for("/static/bootstrap/css/bootstrap.min.css") %]" rel="stylesheet" />
-
-<!-- hydra.css may need to be moved to before boostrap to make the @media rule work. -->
-<link rel="stylesheet" href="[% c.uri_for("/static/css/hydra.css") %]" type="text/css" />
-<link rel="stylesheet" href="[% c.uri_for("/static/css/rotated-th.css") %]" type="text/css" />
-
-<style>
-  .popover { max-width: 40%; }
-</style>
-
-<script type="text/javascript" src="[% c.uri_for("/static/js/bootbox.min.js") %]"></script>
-
-<link rel="stylesheet" href="[% c.uri_for("/static/css/tree.css") %]" type="text/css" />
-
-<script type="text/javascript" src="[% c.uri_for("/static/js/common.js") %]"></script>
--- a/src/script/Makefile.am
+++ b/src/script/Makefile.am
@@ -1,19 +0,0 @@
-EXTRA_DIST =					\
-  $(distributable_scripts)
-
-distributable_scripts =				\
-  hydra-backfill-ids				\
-  hydra-init					\
-  hydra-eval-jobset				\
-  hydra-server					\
-  hydra-update-gc-roots				\
-  hydra-s3-backup-collect-garbage		\
-  hydra-create-user				\
-  hydra-notify					\
-  hydra-send-stats				\
-  nix-prefetch-git				\
-  nix-prefetch-bzr				\
-  nix-prefetch-hg
-
-bin_SCRIPTS =					\
-  $(distributable_scripts)
--- a/src/script/hydra-eval-jobset
+++ b/src/script/hydra-eval-jobset
@@ -85,14 +85,14 @@ sub attrsToSQL {
 # Fetch a store path from 'eval_substituter' if not already present.
 sub getPath {
    my ($path) = @_;
-    return 1 if isValidPath($path);
+    return 1 if $MACHINE_LOCAL_STORE->isValidPath($path);

    my $substituter = $config->{eval_substituter};

    system("nix", "--experimental-features", "nix-command", "copy", "--from", $substituter, "--", $path)
        if defined $substituter;

-    return isValidPath($path);
+    return $MACHINE_LOCAL_STORE->isValidPath($path);
 }


@@ -143,7 +143,7 @@ sub fetchInputBuild {
        , version => $version
        , outputName => $mainOutput->name
        };
-    if (isValidPath($prevBuild->drvpath)) {
+    if ($MACHINE_LOCAL_STORE->isValidPath($prevBuild->drvpath)) {
        $result->{drvPath} = $prevBuild->drvpath;
    }

@@ -233,7 +233,7 @@ sub fetchInputEval {
        my $out = $build->buildoutputs->find({ name => "out" });
        next unless defined $out;
        # FIXME: Should we fail if the path is not valid?
-        next unless isValidPath($out->path);
+        next unless $MACHINE_LOCAL_STORE->isValidPath($out->path);
        $jobs->{$build->get_column('job')} = $out->path;
    }

--- a/src/script/hydra-update-gc-roots
+++ b/src/script/hydra-update-gc-roots
@@ -5,7 +5,6 @@ use warnings;
 use File::Path;
 use File::stat;
 use File::Basename;
-use Nix::Store;
 use Hydra::Config;
 use Hydra::Schema;
 use Hydra::Helper::Nix;
@@ -47,7 +46,7 @@ sub keepBuild {
        $build->finished && ($build->buildstatus == 0 || $build->buildstatus == 6))
    {
        foreach my $path (split / /, $build->get_column('outpaths')) {
-            if (isValidPath($path)) {
+            if ($MACHINE_LOCAL_STORE->isValidPath($path)) {
                addRoot $path;
            } else {
                print STDERR "    warning: output ", $path, " has disappeared\n" if $build->finished;
@@ -55,7 +54,7 @@ sub keepBuild {
        }
    }
    if (!$build->finished || ($keepFailedDrvs && $build->buildstatus != 0)) {
-        if (isValidPath($build->drvpath)) {
+        if ($MACHINE_LOCAL_STORE->isValidPath($build->drvpath)) {
            addRoot $build->drvpath;
        } else {
            print STDERR "    warning: derivation ", $build->drvpath, " has disappeared\n";
--- a/src/script/nix-prefetch-git
+++ b/src/script/nix-prefetch-git
@@ -78,7 +78,7 @@ fi

 init_remote(){
    local url=$1;
-    git init;
+    git init --initial-branch=trunk;
    git remote add origin $url;
 }

--- a/src/sql/Makefile.am
+++ b/src/sql/Makefile.am
@@ -1,9 +0,0 @@
-sqldir = $(libexecdir)/hydra/sql
-nobase_dist_sql_DATA =				\
-  hydra.sql					\
-  test.sql					\
-  upgrade-*.sql					\
-  update-dbix.pl
-
-update-dbix: hydra.sql
-	./update-dbix-harness.sh
--- a/src/sql/meson.build
+++ b/src/sql/meson.build
@@ -0,0 +1,90 @@
+sql_files = files(
+  'hydra.sql',
+  'test.sql',
+  'update-dbix.pl',
+  'upgrade-2.sql',
+  'upgrade-3.sql',
+  'upgrade-4.sql',
+  'upgrade-5.sql',
+  'upgrade-6.sql',
+  'upgrade-7.sql',
+  'upgrade-8.sql',
+  'upgrade-9.sql',
+  'upgrade-10.sql',
+  'upgrade-11.sql',
+  'upgrade-12.sql',
+  'upgrade-13.sql',
+  'upgrade-14.sql',
+  'upgrade-15.sql',
+  'upgrade-16.sql',
+  'upgrade-17.sql',
+  'upgrade-18.sql',
+  'upgrade-19.sql',
+  'upgrade-20.sql',
+  'upgrade-21.sql',
+  'upgrade-22.sql',
+  'upgrade-23.sql',
+  'upgrade-24.sql',
+  'upgrade-25.sql',
+  'upgrade-26.sql',
+  'upgrade-27.sql',
+  'upgrade-28.sql',
+  'upgrade-29.sql',
+  'upgrade-30.sql',
+  'upgrade-31.sql',
+  'upgrade-32.sql',
+  'upgrade-33.sql',
+  'upgrade-34.sql',
+  'upgrade-35.sql',
+  'upgrade-36.sql',
+  'upgrade-37.sql',
+  'upgrade-38.sql',
+  'upgrade-39.sql',
+  'upgrade-40.sql',
+  'upgrade-41.sql',
+  'upgrade-42.sql',
+  'upgrade-43.sql',
+  'upgrade-44.sql',
+  'upgrade-45.sql',
+  'upgrade-46.sql',
+  'upgrade-47.sql',
+  'upgrade-48.sql',
+  'upgrade-49.sql',
+  'upgrade-50.sql',
+  'upgrade-51.sql',
+  'upgrade-52.sql',
+  'upgrade-53.sql',
+  'upgrade-54.sql',
+  'upgrade-55.sql',
+  'upgrade-56.sql',
+  'upgrade-57.sql',
+  'upgrade-58.sql',
+  'upgrade-59.sql',
+  'upgrade-60.sql',
+  'upgrade-61.sql',
+  'upgrade-62.sql',
+  'upgrade-63.sql',
+  'upgrade-64.sql',
+  'upgrade-65.sql',
+  'upgrade-66.sql',
+  'upgrade-67.sql',
+  'upgrade-68.sql',
+  'upgrade-69.sql',
+  'upgrade-70.sql',
+  'upgrade-71.sql',
+  'upgrade-72.sql',
+  'upgrade-73.sql',
+  'upgrade-74.sql',
+  'upgrade-75.sql',
+  'upgrade-76.sql',
+  'upgrade-77.sql',
+  'upgrade-78.sql',
+  'upgrade-79.sql',
+  'upgrade-80.sql',
+  'upgrade-81.sql',
+  'upgrade-82.sql',
+  'upgrade-83.sql',
+  'upgrade-84.sql',
+)
+
+install_data(sql_files, install_dir: hydra_libexecdir / 'sql')
--- a/src/ttf/Makefile.am
+++ b/src/ttf/Makefile.am
@@ -1,4 +0,0 @@
-EXTRA_DIST = COPYING.LIB StayPuft.ttf
-
-ttfdir = $(libexecdir)/hydra/ttf
-nobase_ttf_DATA = $(EXTRA_DIST)
--- a/src/ttf/meson.build
+++ b/src/ttf/meson.build
@@ -0,0 +1,5 @@
+data_files = files(
+  'StayPuft.ttf',
+  'COPYING.LIB',
+)
+install_data(data_files, install_dir: hydra_libexecdir / 'ttf')
--- a/t/Hydra/Controller/Job/builds.t
+++ b/t/Hydra/Controller/Job/builds.t
@@ -54,13 +54,14 @@ subtest "/job/PROJECT/JOBSET/JOB/shield" => sub {

 subtest "/job/PROJECT/JOBSET/JOB/prometheus" => sub {
    my $response = request(GET '/job/' . $project->name . '/' . $jobset->name . '/' . $build->job . '/prometheus');
-    ok($response->is_success, "The page showing the job's prometheus data returns 200.");
-    my $metrics = $response->content;

-    ok($metrics =~ m/hydra_job_failed\{.*\} 0/);
-    ok($metrics =~ m/hydra_job_completion_time\{.*\} [\d]+/);
-    ok($metrics =~ m/hydra_build_closure_size\{.*\} 96/);
-    ok($metrics =~ m/hydra_build_output_size\{.*\} 96/);
+    ok($response->is_success, "The page showing the job's prometheus data returns 200.");
+
+    my $metrics = $response->content;
+    like($metrics, qr/hydra_job_failed\{.*\} 0/);
+    like($metrics, qr/hydra_job_completion_time\{.*\} [\d]+/);
+    like($metrics, qr/hydra_build_closure_size\{.*\} 96/);
+    like($metrics, qr/hydra_build_output_size\{.*\} 96/);
 };

 done_testing;
--- a/t/Hydra/Controller/Jobset/evals.t
+++ b/t/Hydra/Controller/Jobset/evals.t
@@ -32,9 +32,4 @@ subtest "/jobset/PROJECT/JOBSET/evals" => sub {
    ok($jobsetevals->is_success, "The page showing the jobset evals returns 200.");
 };

-subtest "/jobset/PROJECT/JOBSET/errors" => sub {
-    my $jobsetevals = request(GET '/jobset/' . $project->name . '/' . $jobset->name . '/errors');
-    ok($jobsetevals->is_success, "The page showing the jobset eval errors returns 200.");
-};
-
 done_testing;
--- a/t/Hydra/Controller/Jobset/http.t
+++ b/t/Hydra/Controller/Jobset/http.t
@@ -186,7 +186,7 @@ subtest 'Update jobset "job" to have an invalid input type' => sub {
      })
  );
  ok(!$jobsetupdate->is_success);
-  ok($jobsetupdate->content =~ m/Invalid input type.*valid types:/);
+  like($jobsetupdate->content, qr/Invalid input type.*valid types:/);
 };


--- a/t/Hydra/Controller/JobsetEval/fetch.t
+++ b/t/Hydra/Controller/JobsetEval/fetch.t
@@ -35,10 +35,6 @@ subtest "Fetching the eval's overview" => sub {
    is($fetch->code, 200, "channel page is 200");
 };

-subtest "Fetching the eval's overview" => sub {
-    my $fetch = request(GET '/eval/' . $eval->id, '/errors');
-    is($fetch->code, 200, "errors page is 200");
-};


 done_testing;
--- a/t/Hydra/Controller/User/dashboard.t
+++ b/t/Hydra/Controller/User/dashboard.t
@@ -24,7 +24,7 @@ my $cookie = $login->header("set-cookie");
 my $my_jobs = request(GET '/dashboard/alice/my-jobs-tab', Accept => 'application/json', Cookie => $cookie);
 ok($my_jobs->is_success);
 my $content = $my_jobs->content();
-ok($content =~ /empty_dir/);
+like($content, qr/empty_dir/);
 ok(!($content =~ /fails/));
 ok(!($content =~ /succeed_with_failed/));
 done_testing;
--- a/t/Makefile.am
+++ b/t/Makefile.am
@@ -1,39 +0,0 @@
-TESTS_ENVIRONMENT = \
-  BZR_HOME="$(abs_builddir)/data"			\
-  HYDRA_DBI="dbi:Pg:dbname=hydra-test-suite;port=6433"	\
-  HYDRA_DATA="$(abs_builddir)/data"			\
-  HYDRA_HOME="$(top_srcdir)/src"			\
-  HYDRA_CONFIG=						\
-  NIX_REMOTE=						\
-  NIX_REMOTE_SYSTEMS=					\
-  NIX_CONF_DIR="$(abs_builddir)/nix/etc/nix"		\
-  NIX_STATE_DIR="$(abs_builddir)/nix/var/nix"		\
-  NIX_STORE_DIR="$(abs_builddir)/nix/store"			\
-  NIX_LOG_DIR="$(abs_builddir)/nix/var/log/nix"		\
-  PGHOST=/tmp	\
-  PERL5LIB="$(srcdir):$(abs_top_srcdir)/src/lib:$$PERL5LIB"	\
-  PYTHONPATH= \
-  PATH=$(abs_top_srcdir)/src/hydra-evaluator:$(abs_top_srcdir)/src/script:$(abs_top_srcdir)/src/hydra-eval-jobs:$(abs_top_srcdir)/src/hydra-queue-runner:$$PATH \
-  perl -w
-
-EXTRA_DIST = \
-  $(wildcard *.pm) \
-  $(wildcard jobs/*.nix) \
-  $(wildcard jobs/*.sh) \
-  $(TESTS)
-
-TESTS = \
-  perlcritic.pl \
-  test.pl
-
-check_SCRIPTS = repos
-
-repos: dirs
-
-dirs:
-	mkdir -p data
-	touch data/hydra.conf
-	mkdir -p nix
-	mkdir -p nix/etc/nix
-	mkdir -p nix/store
-	mkdir -p nix/var
--- a/t/api-test.t
+++ b/t/api-test.t
@@ -115,7 +115,7 @@ subtest "evaluation" => sub {
        my $build = decode_json(request_json({ uri => "/build/" . $evals->[0]->{builds}->[0] })->content());
        is($build->{job}, "job", "The build's job name is job");
        is($build->{finished}, 0, "The build isn't finished yet");
-        ok($build->{buildoutputs}->{out}->{path} =~ /\/nix\/store\/[a-zA-Z0-9]{32}-job$/, "The build's outpath is in the Nix store and named 'job'");
+        like($build->{buildoutputs}->{out}->{path}, qr/\/nix\/store\/[a-zA-Z0-9]{32}-job$/, "The build's outpath is in the Nix store and named 'job'");

        subtest "search" => sub {
            my $search_project = decode_json(request_json({ uri => "/search/?query=sample" })->content());
--- a/t/content-addressed/basic.t
+++ b/t/content-addressed/basic.t
@@ -27,13 +27,13 @@ my $project = $db->resultset('Projects')->create({name => "tests", displayname =
 my $jobset = createBaseJobset("content-addressed", "content-addressed.nix", $ctx{jobsdir});

 ok(evalSucceeds($jobset), "Evaluating jobs/content-addressed.nix should exit with return code 0");
-is(nrQueuedBuildsForJobset($jobset), 5, "Evaluating jobs/content-addressed.nix should result in 4 builds");
+is(nrQueuedBuildsForJobset($jobset), 6, "Evaluating jobs/content-addressed.nix should result in 6 builds");

 for my $build (queuedBuildsForJobset($jobset)) {
    ok(runBuild($build), "Build '".$build->job."' from jobs/content-addressed.nix should exit with code 0");
    my $newbuild = $db->resultset('Builds')->find($build->id);
    is($newbuild->finished, 1, "Build '".$build->job."' from jobs/content-addressed.nix should be finished.");
-    my $expected = $build->job eq "fails" ? 1 : $build->job =~ /with_failed/ ? 6 : 0;
+    my $expected = $build->job eq "fails" ? 1 : $build->job =~ /with_failed/ ? 6 : $build->job =~ /FailingCA/ ? 2 : 0;
    is($newbuild->buildstatus, $expected, "Build '".$build->job."' from jobs/content-addressed.nix should have buildstatus $expected.");

    my $response = request("/build/".$build->id);
@@ -55,6 +55,8 @@ for my $build (queuedBuildsForJobset($jobset)) {

 }

+# XXX: deststoredir is undefined: Use of uninitialized value $ctx{"deststoredir"} in concatenation (.) or string at t/content-addressed/basic.t line 58.
+# XXX: This test seems to not do what it seems to be doing. See documentation: https://metacpan.org/pod/Test2::V0#isnt($got,-$do_not_want,-$name)
 isnt(<$ctx{deststoredir}/realisations/*>, "", "The destination store should have the realisations of the built derivations registered");

 done_testing;
--- a/t/evaluator/evaluate-constituents-broken.t
+++ b/t/evaluator/evaluate-constituents-broken.t
@@ -22,7 +22,7 @@ like(
    "The stderr record includes a relevant error message"
 );

-$jobset->discard_changes({ '+columns' => {'errormsg' => 'errormsg'} });  # refresh from DB
+$jobset->discard_changes;  # refresh from DB
 like(
    $jobset->errormsg,
    qr/aggregate job ‘mixed_aggregate’ failed with the error: constituentA: does not exist/,
--- a/t/evaluator/evaluate-oom-job.t
+++ b/t/evaluator/evaluate-oom-job.t
@@ -31,6 +31,10 @@ if ($sd_res != 0) {
  skip_all("`systemd-run` returned non-zero when executing `true` (expected 0)");
 }

+# XXX(Mindavi): We should think about how to fix this.
+#               Note that it was always skipped on ofborg/h.n.o (nixos hydra) since systemd-run is not present in the ambient environment there.
+skip_all("Always fails, an error about 'oom' being a string is logged and the process never OOMs. Needs a way to use more memory.");
+
 my $ctx = test_context();

 # Contain the memory usage to 25 MegaBytes using `systemd-run`
--- a/t/jobs/content-addressed.nix
+++ b/t/jobs/content-addressed.nix
@@ -25,6 +25,13 @@ rec {
      FOO = empty_dir;
    };

+  caDependingOnFailingCA =
+    cfg.mkContentAddressedDerivation {
+      name = "ca-depending-on-failing-ca";
+      builder = ./dir-with-file-builder.sh;
+      FOO = fails;
+    };
+
  nonCaDependingOnCA =
    cfg.mkDerivation {
      name = "non-ca-depending-on-ca";
--- a/t/lib/CliRunners.pm
+++ b/t/lib/CliRunners.pm
@@ -14,7 +14,7 @@ our @EXPORT = qw(
 sub evalSucceeds {
    my ($jobset) = @_;
    my ($res, $stdout, $stderr) = captureStdoutStderr(60, ("hydra-eval-jobset", $jobset->project->name, $jobset->name));
-    $jobset->discard_changes({ '+columns' => {'errormsg' => 'errormsg'} });  # refresh from DB
+    $jobset->discard_changes;  # refresh from DB
    if ($res) {
        chomp $stdout; chomp $stderr;
        utf8::decode($stdout) or die "Invalid unicode in stdout.";
@@ -29,7 +29,7 @@ sub evalSucceeds {
 sub evalFails {
    my ($jobset) = @_;
    my ($res, $stdout, $stderr) = captureStdoutStderr(60, ("hydra-eval-jobset", $jobset->project->name, $jobset->name));
-    $jobset->discard_changes({ '+columns' => {'errormsg' => 'errormsg'} });  # refresh from DB
+    $jobset->discard_changes;  # refresh from DB
    if (!$res) {
        chomp $stdout; chomp $stderr;
        utf8::decode($stdout) or die "Invalid unicode in stdout.";
--- a/t/lib/HydraTestContext.pm
+++ b/t/lib/HydraTestContext.pm
@@ -4,6 +4,8 @@ use warnings;
 package HydraTestContext;
 use File::Path qw(make_path);
 use File::Basename;
+use File::Copy::Recursive qw(rcopy);
+use File::Which qw(which);
 use Cwd qw(abs_path getcwd);
 use CliRunners;
 use Hydra::Helper::Exec;
@@ -77,6 +79,13 @@ sub new {
    );
    $ENV{'HYDRA_DBI'} = $pgsql->dsn;

+    my $jobsdir = "$dir/jobs";
+    rcopy(abs_path(dirname(__FILE__) . "/../jobs"), $jobsdir);
+
+    my $coreutils_path = dirname(which 'install');
+    replace_variable_in_file($jobsdir . "/config.nix", '@testPath@', $coreutils_path);
+    replace_variable_in_file($jobsdir . "/declarative/project.json", '@jobsPath@', $jobsdir);
+
    my $self = bless {
        _db => undef,
        db_handle => $pgsql,
@@ -84,7 +93,7 @@ sub new {
        nix_state_dir => $nix_state_dir,
        nix_log_dir => $nix_log_dir,
        testdir => abs_path(dirname(__FILE__) . "/.."),
-        jobsdir => abs_path(dirname(__FILE__) . "/../jobs"),
+        jobsdir => $jobsdir,
        deststoredir => $deststoredir,
    }, $class;

@@ -92,7 +101,7 @@ sub new {
        $opts{'before_init'}->($self);
    }

-    expectOkay(5, ("hydra-init"));
+    expectOkay(30, ("hydra-init"));

    return $self;
 }
@@ -243,6 +252,18 @@ sub write_file {
    close $fh;
 }

+sub replace_variable_in_file {
+    my ($fn, $var, $val) = @_;
+
+    open (my $input, '<', "$fn.in") or die $!;
+    open (my $output, '>', $fn) or die $!;
+
+    while (my $line = <$input>) {
+        $line =~ s/$var/$val/g;
+        print $output $line;
+    }
+}
+
 sub rand_chars {
    return sprintf("t%08X", rand(0xFFFFFFFF));
 }
--- a/t/lib/LDAPContext.pm
+++ b/t/lib/LDAPContext.pm
@@ -70,7 +70,7 @@ sub add_user {
    my $email = $opts{'email'} // "$name\@example";
    my $password = $opts{'password'} // rand_chars();

-    my ($res, $stdout, $stderr) = captureStdoutStderr(1, ("slappasswd", "-s", $password));
+    my ($res, $stdout, $stderr) = captureStdoutStderr(5, ("slappasswd", "-s", $password));
    if ($res) {
        die "Failed to execute slappasswd ($res): $stderr, $stdout";
    }
@@ -178,7 +178,7 @@ sub start {
 sub validateConfig {
    my ($self) = @_;

-    expectOkay(1, ("slaptest", "-u", "-F", $self->{"_slapd_dir"}));
+    expectOkay(5, ("slaptest", "-u", "-F", $self->{"_slapd_dir"}));
 }

 sub _spawn {
@@ -218,7 +218,7 @@ sub load_ldif {

    my $path = "${\$self->{'_tmpdir'}}/load.ldif";
    write_file($path, $content);
-    expectOkay(1, ("slapadd", "-F", $self->{"_slapd_dir"}, "-b", $suffix, "-l", $path));
+    expectOkay(5, ("slapadd", "-F", $self->{"_slapd_dir"}, "-b", $suffix, "-l", $path));
    $self->validateConfig();
 }

--- a/t/meson.build
+++ b/t/meson.build
@@ -0,0 +1,43 @@
+fs = import('fs')
+
+test('perlcritic',
+  perl,
+  args: ['-w', files('perlcritic.pl')],
+  workdir: meson.project_source_root(),
+  timeout: -1,
+)
+
+testenv = environment(
+  {
+    'BZR_HOME': meson.current_build_dir() / 'data',
+    'HYDRA_DBI': 'dbi:Pg:dbname=hydra-test-suite;port=6433',
+    'HYDRA_DATA': meson.current_build_dir() / 'data',
+    'HYDRA_HOME': meson.project_source_root() / 'src',
+    'PGHOST': '/tmp',
+    'PYTHONPATH': '',
+
+    # libpqxx seems to randomly crash with certain values of MALLOC_PERTURB_,
+    # set by default by Meson's test(). Very promising, high quality software.
+    'MALLOC_PERTURB_': '0',
+  },
+)
+testenv.prepend('PERL5LIB',
+  meson.current_source_dir(),
+  meson.project_source_root() / 'src/lib',
+  separator: ':'
+)
+testenv.prepend('PATH',
+  fs.parent(hydra_eval_jobs.full_path()),
+  fs.parent(hydra_evaluator.full_path()),
+  fs.parent(hydra_queue_runner.full_path()),
+  meson.project_source_root() / 'src/script',
+  separator: ':'
+)
+
+test('testsuite',
+  perl,
+  args: ['-I', meson.current_source_dir() / 'lib', '-w', files('test.pl')],
+  env: testenv,
+  workdir: meson.current_source_dir(),
+  timeout: -1,
+)
--- a/t/queue-runner/build-locally-with-substitutable-path.t
+++ b/t/queue-runner/build-locally-with-substitutable-path.t
@@ -39,7 +39,7 @@ subtest "Building, caching, and then garbage collecting the underlying job" => s

    ok(unlink(Hydra::Helper::Nix::gcRootFor($path)), "Unlinking the GC root for underlying Dependency succeeds");

-    (my $ret, my $stdout, my $stderr) = captureStdoutStderr(5, "nix-store", "--delete", $path);
+    (my $ret, my $stdout, my $stderr) = captureStdoutStderr(15, "nix-store", "--delete", $path);
    is($ret, 0, "Deleting the underlying dependency should succeed");
 };

--- a/Show More
+++ b/Show More