WIP: Avoid custom logic copying outputs from the remote builder

We need a replacement for the nar member logic, however. And maybe also a test that fails until this is fixed (this one should not be passing).
Avoid custom logic to copy inputs to the remote builder
2025-02-18 14:08:30 -05:00 · 2025-02-18 14:08:30 -05:00 · 2025-02-18 14:07:42 -05:00 · 2025-02-18 13:00:40 -05:00 · 2025-02-18 12:43:31 -05:00 · 2025-02-16 19:10:10 -05:00
58 changed files with 965 additions and 1532 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`
--- 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/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/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
@@ -1,166 +1,67 @@
 {
  "nodes": {
-    "flake-compat": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1673956053,
-        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
-        "owner": "edolstra",
-        "repo": "flake-compat",
-        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
-        "type": "github"
-      },
-      "original": {
-        "owner": "edolstra",
-        "repo": "flake-compat",
-        "type": "github"
-      }
-    },
-    "flake-parts": {
-      "inputs": {
-        "nixpkgs-lib": [
-          "nix",
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1712014858,
-        "narHash": "sha256-sB4SWl2lX95bExY2gMFG5HIzvva5AVMJd4Igm+GpZNw=",
-        "owner": "hercules-ci",
-        "repo": "flake-parts",
-        "rev": "9126214d0a59633752a136528f5f3b9aa8565b7d",
-        "type": "github"
-      },
-      "original": {
-        "owner": "hercules-ci",
-        "repo": "flake-parts",
-        "type": "github"
-      }
-    },
-    "flake-utils": {
-      "locked": {
-        "lastModified": 1667395993,
-        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
-    "libgit2": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1697646580,
-        "narHash": "sha256-oX4Z3S9WtJlwvj0uH9HlYcWv+x1hqp8mhXl7HsLu2f0=",
-        "owner": "libgit2",
-        "repo": "libgit2",
-        "rev": "45fd9ed7ae1a9b74b957ef4f337bc3c8b3df01b5",
-        "type": "github"
-      },
-      "original": {
-        "owner": "libgit2",
-        "repo": "libgit2",
-        "type": "github"
-      }
-    },
    "nix": {
      "inputs": {
-        "flake-compat": "flake-compat",
-        "flake-parts": "flake-parts",
-        "libgit2": "libgit2",
+        "flake-compat": [],
+        "flake-parts": [],
+        "git-hooks-nix": [],
        "nixpkgs": [
          "nixpkgs"
        ],
-        "nixpkgs-regression": "nixpkgs-regression",
-        "pre-commit-hooks": "pre-commit-hooks"
+        "nixpkgs-23-11": [],
+        "nixpkgs-regression": []
      },
      "locked": {
-        "lastModified": 1713874370,
-        "narHash": "sha256-gW1mO/CvsQQ5gvgiwzxsGhPFI/tx30NING+qgF5Do0s=",
+        "lastModified": 1739899400,
+        "narHash": "sha256-q/RgA4bB7zWai4oPySq9mch7qH14IEeom2P64SXdqHs=",
        "owner": "NixOS",
        "repo": "nix",
-        "rev": "1c8150ac312b5f9ba1b3f6768ff43b09867e5883",
+        "rev": "e310c19a1aeb1ce1ed4d41d5ab2d02db596e0918",
        "type": "github"
      },
      "original": {
        "owner": "NixOS",
-        "ref": "2.22-maintenance",
+        "ref": "2.26-maintenance",
        "repo": "nix",
        "type": "github"
      }
    },
+    "nix-eval-jobs": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1739500569,
+        "narHash": "sha256-3wIReAqdTALv39gkWXLMZQvHyBOc3yPkWT2ZsItxedY=",
+        "owner": "nix-community",
+        "repo": "nix-eval-jobs",
+        "rev": "4b392b284877d203ae262e16af269f702df036bc",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nix-eval-jobs",
+        "type": "github"
+      }
+    },
    "nixpkgs": {
      "locked": {
-        "lastModified": 1712848736,
-        "narHash": "sha256-CzZwhqyLlebljv1zFS2KWVH/3byHND0LfaO1jKsGuVo=",
+        "lastModified": 1739461644,
+        "narHash": "sha256-1o1qR0KYozYGRrnqytSpAhVBYLNBHX+Lv6I39zGRzKM=",
        "owner": "NixOS",
        "repo": "nixpkgs",
-        "rev": "1d6a23f11e44d0fb64b3237569b87658a9eb5643",
+        "rev": "97a719c9f0a07923c957cf51b20b329f9fb9d43f",
        "type": "github"
      },
      "original": {
        "owner": "NixOS",
-        "ref": "nixos-23.11-small",
+        "ref": "nixos-24.11-small",
        "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"
-      }
-    },
-    "pre-commit-hooks": {
-      "inputs": {
-        "flake-compat": [
-          "nix"
-        ],
-        "flake-utils": "flake-utils",
-        "gitignore": [
-          "nix"
-        ],
-        "nixpkgs": [
-          "nix",
-          "nixpkgs"
-        ],
-        "nixpkgs-stable": [
-          "nix",
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1712897695,
-        "narHash": "sha256-nMirxrGteNAl9sWiOhoN5tIHyjBbVi5e2tgZUgZlK3Y=",
-        "owner": "cachix",
-        "repo": "pre-commit-hooks.nix",
-        "rev": "40e6053ecb65fcbf12863338a6dcefb3f55f1bf8",
-        "type": "github"
-      },
-      "original": {
-        "owner": "cachix",
-        "repo": "pre-commit-hooks.nix",
-        "type": "github"
-      }
-    },
    "root": {
      "inputs": {
        "nix": "nix",
+        "nix-eval-jobs": "nix-eval-jobs",
        "nixpkgs": "nixpkgs"
      }
    }
--- a/flake.nix
+++ b/flake.nix
@@ -1,35 +1,44 @@
 {
  description = "A Nix-based continuous build system";

-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11-small";
-  inputs.nix.url = "github:NixOS/nix/2.22-maintenance";
-  inputs.nix.inputs.nixpkgs.follows = "nixpkgs";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11-small";

-  outputs = { self, nixpkgs, nix }:
+  inputs.nix = {
+    url = "github:NixOS/nix/2.26-maintenance";
+    inputs.nixpkgs.follows = "nixpkgs";
+
+    # hide nix dev tooling from our lock file
+    inputs.flake-parts.follows = "";
+    inputs.git-hooks-nix.follows = "";
+    inputs.nixpkgs-regression.follows = "";
+    inputs.nixpkgs-23-11.follows = "";
+    inputs.flake-compat.follows = "";
+  };
+
+  inputs.nix-eval-jobs = {
+    url = "github:nix-community/nix-eval-jobs";
+    # We want to control the deps precisely
+    flake = false;
+  };
+
+  outputs = { self, nixpkgs, nix, nix-eval-jobs, ... }:
    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;
-      });
-
    in
    rec {

      # A Nixpkgs overlay that provides a 'hydra' package.
      overlays.default = final: prev: {
+        nix-eval-jobs = final.callPackage nix-eval-jobs {};
        hydra = final.callPackage ./package.nix {
          inherit (nixpkgs.lib) fileset;
          rawSrc = self;
+          nix-perl-bindings = final.nixComponents.nix-perl-bindings;
        };
      };

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

        buildNoTests = forEachSystem (system:
@@ -38,19 +47,21 @@
          })
        );

-        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 = import ./nixos-tests.nix {
-          inherit forEachSystem nixpkgs pkgsBySystem nixosModules;
+          inherit forEachSystem nixpkgs nixosModules;
        };

        container = nixosConfigurations.container.config.system.build.toplevel;
@@ -63,12 +74,26 @@
      });

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

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

      nixosConfigurations.container = nixpkgs.lib.nixosSystem {
@@ -76,7 +101,6 @@
        modules =
          [
            self.nixosModules.hydra
-            self.nixosModules.overlayNixpkgsForThisHydra
            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_util_dep = dependency('nix-util', required: true)
+nix_store_dep = dependency('nix-store', required: true)
+nix_main_dep = dependency('nix-main', required: true)
+
+# Nix need extra flags not provided in its pkg-config files.
+nix_dep = declare_dependency(
+  dependencies: [
+    nix_util_dep,
+    nix_store_dep,
+    nix_main_dep,
+  ],
+  compile_args: [
+    '-include', 'nix/config-util.hh',
+    '-include', 'nix/config-store.hh',
+    '-include', 'nix/config-main.hh',
+  ],
+)
+
+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
@@ -1,11 +1,10 @@
-{ overlays }:
+{ self }:

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

  hydraTest = { pkgs, ... }: {
--- a/nixos-modules/hydra.nix
+++ b/nixos-modules/hydra.nix
@@ -68,8 +68,6 @@ in

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

@@ -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 ];
@@ -464,10 +463,12 @@ in
          ''
            set -eou pipefail
            compression=$(sed -nr 's/compress_build_logs_compression = ()/\1/p' ${baseDir}/hydra.conf)
-            if [[ $compression == zstd ]]; then
+            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
+            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
@@ -1,13 +1,12 @@
-{ forEachSystem, nixpkgs, pkgsBySystem, nixosModules }:
+{ forEachSystem, nixpkgs, nixosModules }:

 let
  # NixOS configuration used for VM tests.
  hydraServer =
-    { config, pkgs, ... }:
+    { pkgs, ... }:
    {
      imports = [
        nixosModules.hydra
-        nixosModules.overlayNixpkgsForThisHydra
        nixosModules.hydraTest
      ];

@@ -44,11 +43,10 @@ in
    });

  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, ... }: {
+      nodes.machine = {
        imports = [ hydraServer ];
        services.hydra-dev.extraConfig = ''
          <influxdb>
@@ -89,7 +87,7 @@ in

        # 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"
+            "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
@@ -103,7 +101,7 @@ in
    });

  gitea = forEachSystem (system:
-    let pkgs = pkgsBySystem.${system}; in
+    let pkgs = nixpkgs.legacyPackages.${system}; in
    with import (nixpkgs + "/nixos/lib/testing-python.nix") { inherit system; };
    makeTest {
      name = "hydra-gitea";
@@ -298,7 +296,7 @@ in
    });

  validate-openapi = forEachSystem (system:
-    let pkgs = pkgsBySystem.${system}; in
+    let pkgs = nixpkgs.legacyPackages.${system}; in
    pkgs.runCommand "validate-openapi"
    { buildInputs = [ pkgs.openapi-generator-cli ]; }
    ''
--- a/package.nix
+++ b/package.nix
@@ -8,11 +8,16 @@

 , perlPackages

-, nix
+, nix-util
+, nix-store
+, nix-main
+, nix-cli
+, nix-perl-bindings
 , git

 , makeWrapper
-, autoreconfHook
+, meson
+, ninja
 , nukeReferences
 , pkg-config
 , mdbook
@@ -48,6 +53,7 @@
 , xz
 , gnutar
 , gnused
+, nix-eval-jobs

 , rpm
 , dpkg
@@ -59,7 +65,7 @@ let
    name = "hydra-perl-deps";
    paths = lib.closePropagation
      ([
-        nix.perl-bindings
+        nix-perl-bindings
        git
      ] ++ (with perlPackages; [
        AuthenSASL
@@ -90,6 +96,7 @@ let
        DigestSHA1
        EmailMIME
        EmailSender
+        FileCopyRecursive
        FileLibMagic
        FileSlurper
        FileWhich
@@ -137,32 +144,28 @@ 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
-    nix
+    nix-cli
    perlDeps
    perl
    unzip
@@ -172,7 +175,9 @@ stdenv.mkDerivation (finalAttrs: {
    libpqxx
    openssl
    libxslt
-    nix
+    nix-util
+    nix-store
+    nix-main
    perlDeps
    perl
    boost
@@ -191,6 +196,7 @@ stdenv.mkDerivation (finalAttrs: {
    openldap
    postgresql_13
    pixz
+    nix-eval-jobs
  ];

  checkInputs = [
@@ -198,13 +204,14 @@ stdenv.mkDerivation (finalAttrs: {
    glibcLocales
    libressl.nc
    python3
+    nix-cli
  ];

  hydraPath = lib.makeBinPath (
    [
      subversion
      openssh
-      nix
+      nix-cli
      coreutils
      findutils
      pixz
@@ -219,15 +226,22 @@ stdenv.mkDerivation (finalAttrs: {
      darcs
      gnused
      breezy
+      nix-eval-jobs
    ] ++ lib.optionals stdenv.isLinux [ rpm dpkg cdrkit ]
  );

  OPENLDAP_ROOT = openldap;

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

-    PATH=$(pwd)/src/hydra-evaluator:$(pwd)/src/script:$(pwd)/src/hydra-eval-jobs:$(pwd)/src/hydra-queue-runner:$PATH
+    PATH=$(pwd)/src/hydra-evaluator:$(pwd)/src/script:$(pwd)/src/hydra-queue-runner:$PATH
    PERL5LIB=$(pwd)/src/lib:$PERL5LIB
    export HYDRA_HOME="$(pwd)/src/"
    mkdir -p .hydra-data
@@ -237,14 +251,11 @@ 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)
@@ -261,12 +272,13 @@ stdenv.mkDerivation (finalAttrs: {
            --prefix PATH ':' $out/bin:$hydraPath \
            --set HYDRA_RELEASE ${version} \
            --set HYDRA_HOME $out/libexec/hydra \
-            --set NIX_RELEASE ${nix.name or "unknown"}
+            --set NIX_RELEASE ${nix-cli.name or "unknown"} \
+            --set NIX_EVAL_JOBS_RELEASE ${nix-eval-jobs.name or "unknown"}
    done
  '';

  dontStrip = true;

  meta.description = "Build of Hydra on ${stdenv.system}";
-  passthru = { inherit perlDeps nix; };
+  passthru = { inherit perlDeps; };
 })
--- 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
@@ -1,579 +0,0 @@
-#include <iostream>
-#include <thread>
-#include <optional>
-#include <unordered_map>
-
-#include "shared.hh"
-#include "store-api.hh"
-#include "eval.hh"
-#include "eval-inline.hh"
-#include "eval-settings.hh"
-#include "signals.hh"
-#include "terminal.hh"
-#include "util.hh"
-#include "get-drvs.hh"
-#include "globals.hh"
-#include "common-eval-args.hh"
-#include "flake/flakeref.hh"
-#include "flake/flake.hh"
-#include "attr-path.hh"
-#include "derivations.hh"
-#include "local-fs-store.hh"
-
-#include "hydra-config.hh"
-
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <sys/resource.h>
-
-#include <nlohmann/json.hpp>
-
-void check_pid_status_nonblocking(pid_t check_pid)
-{
-    // Only check 'initialized' and known PID's
-    if (check_pid <= 0) { return; }
-
-    int wstatus = 0;
-    pid_t pid = waitpid(check_pid, &wstatus, WNOHANG);
-    // -1 = failure, WNOHANG: 0 = no change
-    if (pid <= 0) { return; }
-
-    std::cerr << "child process (" << pid << ") ";
-
-    if (WIFEXITED(wstatus)) {
-        std::cerr << "exited with status=" << WEXITSTATUS(wstatus) << std::endl;
-    } else if (WIFSIGNALED(wstatus)) {
-        std::cerr << "killed by signal=" << WTERMSIG(wstatus) << std::endl;
-    } else if (WIFSTOPPED(wstatus)) {
-        std::cerr << "stopped by signal=" << WSTOPSIG(wstatus) << std::endl;
-    } else if (WIFCONTINUED(wstatus)) {
-        std::cerr << "continued" << std::endl;
-    }
-}
-
-using namespace nix;
-
-static Path gcRootsDir;
-static size_t maxMemorySize;
-
-struct MyArgs : MixEvalArgs, MixCommonArgs, RootArgs
-{
-    Path releaseExpr;
-    bool flake = false;
-    bool dryRun = false;
-
-    MyArgs() : MixCommonArgs("hydra-eval-jobs")
-    {
-        addFlag({
-            .longName = "gc-roots-dir",
-            .description = "garbage collector roots directory",
-            .labels = {"path"},
-            .handler = {&gcRootsDir}
-        });
-
-        addFlag({
-            .longName = "dry-run",
-            .description = "don't create store derivations",
-            .handler = {&dryRun, true}
-        });
-
-        addFlag({
-            .longName = "flake",
-            .description = "build a flake",
-            .handler = {&flake, true}
-        });
-
-        expectArg("expr", &releaseExpr);
-    }
-};
-
-static MyArgs myArgs;
-
-static std::string queryMetaStrings(EvalState & state, PackageInfo & drv, const std::string & name, const std::string & subAttribute)
-{
-    Strings res;
-    std::function<void(Value & v)> rec;
-
-    rec = [&](Value & v) {
-        state.forceValue(v, noPos);
-        if (v.type() == nString)
-            res.emplace_back(v.string_view());
-        else if (v.isList())
-            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())
-                res.push_back(std::string(state.forceString(*a->value, a->pos, "while evaluating meta attributes")));
-        }
-    };
-
-    Value * v = drv.queryMeta(name);
-    if (v) rec(*v);
-
-    return concatStringsSep(", ", res);
-}
-
-static void worker(
-    EvalState & state,
-    Bindings & autoArgs,
-    AutoCloseFD & to,
-    AutoCloseFD & from)
-{
-    Value vTop;
-
-    if (myArgs.flake) {
-        using namespace flake;
-
-        auto flakeRef = parseFlakeRef(myArgs.releaseExpr);
-
-        auto vFlake = state.allocValue();
-
-        auto lockedFlake = lockFlake(state, flakeRef,
-            LockFlags {
-                .updateLockFile = false,
-                .useRegistries = false,
-                .allowUnlocked = false,
-            });
-
-        callFlake(state, lockedFlake, *vFlake);
-
-        auto vOutputs = vFlake->attrs()->get(state.symbols.create("outputs"))->value;
-        state.forceValue(*vOutputs, noPos);
-
-        auto aHydraJobs = vOutputs->attrs()->get(state.symbols.create("hydraJobs"));
-        if (!aHydraJobs)
-            aHydraJobs = vOutputs->attrs()->get(state.symbols.create("checks"));
-        if (!aHydraJobs)
-            throw Error("flake '%s' does not provide any Hydra jobs or checks", flakeRef);
-
-        vTop = *aHydraJobs->value;
-
-    } else {
-        state.evalFile(lookupFileArg(state, myArgs.releaseExpr), vTop);
-    }
-
-    auto vRoot = state.allocValue();
-    state.autoCallFunction(autoArgs, vTop, *vRoot);
-
-    while (true) {
-        /* Wait for the master to send us a job name. */
-        writeLine(to.get(), "next");
-
-        auto s = readLine(from.get());
-        if (s == "exit") break;
-        if (!hasPrefix(s, "do ")) abort();
-        std::string attrPath(s, 3);
-
-        debug("worker process %d at '%s'", getpid(), attrPath);
-
-        /* Evaluate it and send info back to the master. */
-        nlohmann::json reply;
-
-        try {
-            auto vTmp = findAlongAttrPath(state, attrPath, autoArgs, *vRoot).first;
-
-            auto v = state.allocValue();
-            state.autoCallFunction(autoArgs, *vTmp, *v);
-
-            if (auto drv = getDerivation(state, *v, false)) {
-
-                // CA derivations do not have static output paths, so we
-                // have to defensively not query output paths in case we
-                // encounter one.
-                PackageInfo::Outputs outputs = drv->queryOutputs(
-                    !experimentalFeatureSettings.isEnabled(Xp::CaDerivations));
-
-                if (drv->querySystem() == "unknown")
-                    state.error<EvalError>("derivation must have a 'system' attribute").debugThrow();
-
-                auto drvPath = state.store->printStorePath(drv->requireDrvPath());
-
-                nlohmann::json job;
-
-                job["nixName"] = drv->queryName();
-                job["system"] =drv->querySystem();
-                job["drvPath"] = drvPath;
-                job["description"] = drv->queryMetaString("description");
-                job["license"] = queryMetaStrings(state, *drv, "license", "shortName");
-                job["homepage"] = drv->queryMetaString("homepage");
-                job["maintainers"] = queryMetaStrings(state, *drv, "maintainers", "email");
-                job["schedulingPriority"] = drv->queryMetaInt("schedulingPriority", 100);
-                job["timeout"] = drv->queryMetaInt("timeout", 36000);
-                job["maxSilent"] = drv->queryMetaInt("maxSilent", 7200);
-                job["isChannel"] = drv->queryMetaBool("isHydraChannel", false);
-
-                /* If this is an aggregate, then get its constituents. */
-                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"));
-                    if (!a)
-                        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);
-                    for (auto & c : context)
-                        std::visit(overloaded {
-                            [&](const NixStringContextElem::Built & b) {
-                                job["constituents"].push_back(b.drvPath->to_string(*state.store));
-                            },
-                            [&](const NixStringContextElem::Opaque & o) {
-                            },
-                            [&](const NixStringContextElem::DrvDeep & d) {
-                            },
-                        }, c.raw);
-
-                    state.forceList(*a->value, a->pos, "while evaluating the `constituents` attribute");
-                    for (unsigned int n = 0; n < a->value->listSize(); ++n) {
-                        auto v = a->value->listElems()[n];
-                        state.forceValue(*v, noPos);
-                        if (v->type() == nString)
-                            job["namedConstituents"].push_back(v->string_view());
-                    }
-                }
-
-                /* Register the derivation as a GC root.  !!! This
-                   registers roots for jobs that we may have already
-                   done. */
-                auto localStore = state.store.dynamic_pointer_cast<LocalFSStore>();
-                if (gcRootsDir != "" && localStore) {
-                    Path root = gcRootsDir + "/" + std::string(baseNameOf(drvPath));
-                    if (!pathExists(root))
-                        localStore->addPermRoot(localStore->parseStorePath(drvPath), root);
-                }
-
-                nlohmann::json out;
-                for (auto & [outputName, optOutputPath] : outputs) {
-                    if (optOutputPath) {
-                        out[outputName] = state.store->printStorePath(*optOutputPath);
-                    } else {
-                        // See the `queryOutputs` call above; we should
-                        // not encounter missing output paths otherwise.
-                        assert(experimentalFeatureSettings.isEnabled(Xp::CaDerivations));
-                        out[outputName] = nullptr;
-                    }
-                }
-                job["outputs"] = std::move(out);
-                reply["job"] = std::move(job);
-            }
-
-            else if (v->type() == nAttrs) {
-                auto attrs = nlohmann::json::array();
-                StringSet ss;
-                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);
-                        continue;
-                    }
-                    attrs.push_back(name);
-                }
-                reply["attrs"] = std::move(attrs);
-            }
-
-            else if (v->type() == nNull)
-                ;
-
-            else state.error<TypeError>("attribute '%s' is %s, which is not supported", attrPath, showType(*v)).debugThrow();
-
-        } catch (EvalError & e) {
-            auto msg = e.msg();
-            // Transmits the error we got from the previous evaluation
-            // in the JSON output.
-            reply["error"] = filterANSIEscapes(msg, true);
-            // Don't forget to print it into the STDERR log, this is
-            // what's shown in the Hydra UI.
-            printError(msg);
-        }
-
-        writeLine(to.get(), reply.dump());
-
-        /* If our RSS exceeds the maximum, exit. The master will
-           start a new process. */
-        struct rusage r;
-        getrusage(RUSAGE_SELF, &r);
-        if ((size_t) r.ru_maxrss > maxMemorySize * 1024) break;
-    }
-
-    writeLine(to.get(), "restart");
-}
-
-int main(int argc, char * * argv)
-{
-    /* Prevent undeclared dependencies in the evaluation via
-       $NIX_PATH. */
-    unsetenv("NIX_PATH");
-
-    return handleExceptions(argv[0], [&]() {
-
-        auto config = std::make_unique<HydraConfig>();
-
-        auto nrWorkers = config->getIntOption("evaluator_workers", 1);
-        maxMemorySize = config->getIntOption("evaluator_max_memory_size", 4096);
-
-        initNix();
-        initGC();
-
-        myArgs.parseCmdline(argvToStrings(argc, argv));
-
-        auto pureEval = config->getBoolOption("evaluator_pure_eval", myArgs.flake);
-
-        /* FIXME: The build hook in conjunction with import-from-derivation is causing "unexpected EOF" during eval */
-        settings.builders = "";
-
-        /* Prevent access to paths outside of the Nix search path and
-           to the environment. */
-        evalSettings.restrictEval = true;
-
-        /* When building a flake, use pure evaluation (no access to
-           'getEnv', 'currentSystem' etc. */
-        evalSettings.pureEval = pureEval;
-
-        if (myArgs.dryRun) settings.readOnlyMode = true;
-
-        if (myArgs.releaseExpr == "") throw UsageError("no expression specified");
-
-        if (gcRootsDir == "") printMsg(lvlError, "warning: `--gc-roots-dir' not specified");
-
-        struct State
-        {
-            std::set<std::string> todo{""};
-            std::set<std::string> active;
-            nlohmann::json jobs;
-            std::exception_ptr exc;
-        };
-
-        std::condition_variable wakeup;
-
-        Sync<State> state_;
-
-        /* Start a handler thread per worker process. */
-        auto handler = [&]()
-        {
-            pid_t pid = -1;
-            try {
-                AutoCloseFD from, to;
-
-                while (true) {
-
-                    /* Start a new worker process if necessary. */
-                    if (pid == -1) {
-                        Pipe toPipe, fromPipe;
-                        toPipe.create();
-                        fromPipe.create();
-                        pid = startProcess(
-                            [&,
-                             to{std::make_shared<AutoCloseFD>(std::move(fromPipe.writeSide))},
-                             from{std::make_shared<AutoCloseFD>(std::move(toPipe.readSide))}
-                            ]()
-                            {
-                                try {
-                                    EvalState state(myArgs.lookupPath, openStore());
-                                    Bindings & autoArgs = *myArgs.getAutoArgs(state);
-                                    worker(state, autoArgs, *to, *from);
-                                } catch (Error & e) {
-                                    nlohmann::json err;
-                                    auto msg = e.msg();
-                                    err["error"] = filterANSIEscapes(msg, true);
-                                    printError(msg);
-                                    writeLine(to->get(), err.dump());
-                                    // Don't forget to print it into the STDERR log, this is
-                                    // what's shown in the Hydra UI.
-                                    writeLine(to->get(), "restart");
-                                }
-                            },
-                            ProcessOptions { .allowVfork = false });
-                        from = std::move(fromPipe.readSide);
-                        to = std::move(toPipe.writeSide);
-                        debug("created worker process %d", pid);
-                    }
-
-                    /* Check whether the existing worker process is still there. */
-                    auto s = readLine(from.get());
-                    if (s == "restart") {
-                        pid = -1;
-                        continue;
-                    } else if (s != "next") {
-                        auto json = nlohmann::json::parse(s);
-                        throw Error("worker error: %s", (std::string) json["error"]);
-                    }
-
-                    /* Wait for a job name to become available. */
-                    std::string attrPath;
-
-                    while (true) {
-                        checkInterrupt();
-                        auto state(state_.lock());
-                        if ((state->todo.empty() && state->active.empty()) || state->exc) {
-                            writeLine(to.get(), "exit");
-                            return;
-                        }
-                        if (!state->todo.empty()) {
-                            attrPath = *state->todo.begin();
-                            state->todo.erase(state->todo.begin());
-                            state->active.insert(attrPath);
-                            break;
-                        } else
-                            state.wait(wakeup);
-                    }
-
-                    /* Tell the worker to evaluate it. */
-                    writeLine(to.get(), "do " + attrPath);
-
-                    /* Wait for the response. */
-                    auto response = nlohmann::json::parse(readLine(from.get()));
-
-                    /* Handle the response. */
-                    StringSet newAttrs;
-
-                    if (response.find("job") != response.end()) {
-                        auto state(state_.lock());
-                        state->jobs[attrPath] = response["job"];
-                    }
-
-                    if (response.find("attrs") != response.end()) {
-                        for (auto & i : response["attrs"]) {
-                            std::string path = i;
-                            if (path.find(".") != std::string::npos){
-                                path = "\"" + path  + "\"";
-                            }
-                            auto s = (attrPath.empty() ? "" : attrPath + ".") + (std::string) path;
-                            newAttrs.insert(s);
-                        }
-                    }
-
-                    if (response.find("error") != response.end()) {
-                        auto state(state_.lock());
-                        state->jobs[attrPath]["error"] = response["error"];
-                    }
-
-                    /* Add newly discovered job names to the queue. */
-                    {
-                        auto state(state_.lock());
-                        state->active.erase(attrPath);
-                        for (auto & s : newAttrs)
-                            state->todo.insert(s);
-                        wakeup.notify_all();
-                    }
-                }
-            } catch (...) {
-                check_pid_status_nonblocking(pid);
-                auto state(state_.lock());
-                state->exc = std::current_exception();
-                wakeup.notify_all();
-            }
-        };
-
-        std::vector<std::thread> threads;
-        for (size_t i = 0; i < nrWorkers; i++)
-            threads.emplace_back(std::thread(handler));
-
-        for (auto & thread : threads)
-            thread.join();
-
-        auto state(state_.lock());
-
-        if (state->exc)
-            std::rethrow_exception(state->exc);
-
-        /* For aggregate jobs that have named consistuents
-           (i.e. constituents that are a job name rather than a
-           derivation), look up the referenced job and add it to the
-           dependencies of the aggregate derivation. */
-        auto store = openStore();
-
-        for (auto i = state->jobs.begin(); i != state->jobs.end(); ++i) {
-            auto jobName = i.key();
-            auto & job = i.value();
-
-            auto named = job.find("namedConstituents");
-            if (named == job.end()) continue;
-
-            std::unordered_map<std::string, std::string> brokenJobs;
-            auto getNonBrokenJobOrRecordError = [&brokenJobs, &jobName, &state](
-                    const std::string & childJobName) -> std::optional<nlohmann::json> {
-                auto childJob = state->jobs.find(childJobName);
-                if (childJob == state->jobs.end()) {
-                    printError("aggregate job '%s' references non-existent job '%s'", jobName, childJobName);
-                    brokenJobs[childJobName] = "does not exist";
-                    return std::nullopt;
-                }
-                if (childJob->find("error") != childJob->end()) {
-                    std::string error = (*childJob)["error"];
-                    printError("aggregate job '%s' references broken job '%s': %s", jobName, childJobName, error);
-                    brokenJobs[childJobName] = error;
-                    return std::nullopt;
-                }
-                return *childJob;
-            };
-
-            if (myArgs.dryRun) {
-                for (std::string jobName2 : *named) {
-                    auto job2 = getNonBrokenJobOrRecordError(jobName2);
-                    if (!job2) {
-                        continue;
-                    }
-                    std::string drvPath2 = (*job2)["drvPath"];
-                    job["constituents"].push_back(drvPath2);
-                }
-            } else {
-                auto drvPath = store->parseStorePath((std::string) job["drvPath"]);
-                auto drv = store->readDerivation(drvPath);
-
-                for (std::string jobName2 : *named) {
-                    auto job2 = getNonBrokenJobOrRecordError(jobName2);
-                    if (!job2) {
-                        continue;
-                    }
-                    auto drvPath2 = store->parseStorePath((std::string) (*job2)["drvPath"]);
-                    auto drv2 = store->readDerivation(drvPath2);
-                    job["constituents"].push_back(store->printStorePath(drvPath2));
-                    drv.inputDrvs.map[drvPath2].value = {drv2.outputs.begin()->first};
-                }
-
-                if (brokenJobs.empty()) {
-                    std::string drvName(drvPath.name());
-                    assert(hasSuffix(drvName, drvExtension));
-                    drvName.resize(drvName.size() - drvExtension.size());
-
-                    auto hashModulo = hashDerivationModulo(*store, drv, true);
-                    if (hashModulo.kind != DrvHash::Kind::Regular) continue;
-                    auto h = hashModulo.hashes.find("out");
-                    if (h == hashModulo.hashes.end()) continue;
-                    auto outPath = store->makeOutputPath("out", h->second, drvName);
-                    drv.env["out"] = store->printStorePath(outPath);
-                    drv.outputs.insert_or_assign("out", DerivationOutput::InputAddressed { .path = outPath });
-                    auto newDrvPath = store->printStorePath(writeDerivation(*store, drv));
-
-                    debug("rewrote aggregate derivation %s -> %s", store->printStorePath(drvPath), newDrvPath);
-
-                    job["drvPath"] = newDrvPath;
-                    job["outputs"]["out"] = store->printStorePath(outPath);
-                }
-            }
-
-            job.erase("namedConstituents");
-
-            /* Register the derivation as a GC root.  !!! This
-                registers roots for jobs that we may have already
-                done. */
-            auto localStore = store.dynamic_pointer_cast<LocalFSStore>();
-            if (gcRootsDir != "" && localStore) {
-                auto drvPath = job["drvPath"].get<std::string>();
-                Path root = gcRootsDir + "/" + std::string(baseNameOf(drvPath));
-                if (!pathExists(root))
-                    localStore->addPermRoot(localStore->parseStorePath(drvPath), root);
-            }
-
-            if (!brokenJobs.empty()) {
-                std::stringstream ss;
-                for (const auto& [jobName, error] : brokenJobs) {
-                    ss << jobName << ": " << error << "\n";
-                }
-                job["error"] = ss.str();
-            }
-        }
-
-        std::cout << state->jobs.dump(2) << "\n";
-    });
-}
--- 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/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
@@ -7,140 +7,35 @@

 #include "build-result.hh"
 #include "path.hh"
+#include "legacy-ssh-store.hh"
 #include "serve-protocol.hh"
-#include "serve-protocol-impl.hh"
 #include "state.hh"
 #include "current-process.hh"
 #include "processes.hh"
 #include "util.hh"
-#include "serve-protocol.hh"
-#include "serve-protocol-impl.hh"
 #include "ssh.hh"
 #include "finally.hh"
 #include "url.hh"

 using namespace nix;

+bool ::Machine::isLocalhost() const
+{
+    return storeUri.params.empty() && std::visit(overloaded {
+        [](const StoreReference::Auto &) {
+            return true;
+        },
+        [](const StoreReference::Specified & s) {
+            return
+               (s.scheme == "local" || s.scheme == "unix") ||
+               ((s.scheme == "ssh" || s.scheme == "ssh-ng") &&
+                s.authority == "localhost");
+        },
+    }, storeUri.variant);
+}
+
 namespace nix::build_remote {

-static Strings extraStoreArgs(std::string & machine)
-{
-    Strings result;
-    try {
-        auto parsed = parseURL(machine);
-        if (parsed.scheme != "ssh") {
-            throw SysError("Currently, only (legacy-)ssh stores are supported!");
-        }
-        machine = parsed.authority.value_or("");
-        auto remoteStore = parsed.query.find("remote-store");
-        if (remoteStore != parsed.query.end()) {
-            result = {"--store", shellEscape(remoteStore->second)};
-        }
-    } catch (BadURL &) {
-        // We just try to continue with `machine->sshName` here for backwards compat.
-    }
-
-    return result;
-}
-
-static std::unique_ptr<SSHMaster::Connection> openConnection(
-    ::Machine::ptr machine, SSHMaster & master)
-{
-    Strings command = {"nix-store", "--serve", "--write"};
-    if (machine->isLocalhost()) {
-        command.push_back("--builders");
-        command.push_back("");
-    } else {
-        command.splice(command.end(), extraStoreArgs(machine->sshName));
-    }
-
-    auto ret = master.startCommand(std::move(command), {
-        "-a", "-oBatchMode=yes", "-oConnectTimeout=60", "-oTCPKeepAlive=yes"
-    });
-
-    // 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(ret->in.get(), F_SETPIPE_SZ, &pipesize);
-    fcntl(ret->out.get(), F_SETPIPE_SZ, &pipesize);
-
-    return ret;
-}
-
-
-static void copyClosureTo(
-    ::Machine::Connection & conn,
-    Store & destStore,
-    const StorePathSet & paths,
-    SubstituteFlag useSubstitutes = NoSubstitute)
-{
-    StorePathSet closure;
-    destStore.computeFSClosure(paths, closure);
-
-    /* Send the "query valid paths" command with the "lock" option
-       enabled. This prevents a race where the remote host
-       garbage-collect paths that are already there. Optionally, ask
-       the remote host to substitute missing paths. */
-    // FIXME: substitute output pollutes our build log
-    /* Get back the set of paths that are already valid on the remote
-       host. */
-    auto present = conn.queryValidPaths(
-        destStore, true, closure, useSubstitutes);
-
-    if (present.size() == closure.size()) return;
-
-    auto sorted = destStore.topoSortPaths(closure);
-
-    StorePathSet missing;
-    for (auto i = sorted.rbegin(); i != sorted.rend(); ++i)
-        if (!present.count(*i)) missing.insert(*i);
-
-    printMsg(lvlDebug, "sending %d missing paths", missing.size());
-
-    std::unique_lock<std::timed_mutex> sendLock(conn.machine->state->sendLock,
-        std::chrono::seconds(600));
-
-    conn.to << ServeProto::Command::ImportPaths;
-    destStore.exportPaths(missing, conn.to);
-    conn.to.flush();
-
-    if (readInt(conn.from) != 1)
-        throw Error("remote machine failed to import closure");
-}
-
-
-// FIXME: use Store::topoSortPaths().
-static StorePaths reverseTopoSortPaths(const std::map<StorePath, UnkeyedValidPathInfo> & paths)
-{
-    StorePaths sorted;
-    StorePathSet visited;
-
-    std::function<void(const StorePath & path)> dfsVisit;
-
-    dfsVisit = [&](const StorePath & path) {
-        if (!visited.insert(path).second) return;
-
-        auto info = paths.find(path);
-        auto references = info == paths.end() ? StorePathSet() : info->second.references;
-
-        for (auto & i : references)
-            /* Don't traverse into paths that don't exist.  That can
-               happen due to substitutes for non-existent paths. */
-            if (i != path && paths.count(i))
-                dfsVisit(i);
-
-        sorted.push_back(path);
-    };
-
-    for (auto & i : paths)
-        dfsVisit(i.first);
-
-    return sorted;
-}
-
 static std::pair<Path, AutoCloseFD> openLogFile(const std::string & logDir, const StorePath & drvPath)
 {
    std::string base(drvPath.to_string());
@@ -198,18 +93,18 @@ static BasicDerivation sendInputs(
        MaintainCount<counter> mc2(nrStepsCopyingTo);

        printMsg(lvlDebug, "sending closure of ‘%s’ to ‘%s’",
-            localStore.printStorePath(step.drvPath), conn.machine->sshName);
+            localStore.printStorePath(step.drvPath), conn.machine->storeUri.render());

        auto now1 = std::chrono::steady_clock::now();

        /* Copy the input closure. */
-        if (conn.machine->isLocalhost()) {
-            StorePathSet closure;
-            destStore.computeFSClosure(basicDrv.inputSrcs, closure);
-            copyPaths(destStore, localStore, closure, NoRepair, NoCheckSigs, NoSubstitute);
-        } else {
-            copyClosureTo(conn, destStore, basicDrv.inputSrcs, Substitute);
-        }
+        copyClosure(
+            destStore,
+            conn.machine->isLocalhost() ? localStore : *conn.store,
+            basicDrv.inputSrcs,
+            NoRepair,
+            NoCheckSigs,
+            Substitute);

        auto now2 = std::chrono::steady_clock::now();

@@ -228,7 +123,7 @@ static BuildResult performBuild(
    counter & nrStepsBuilding
 )
 {
-    conn.putBuildDerivationRequest(localStore, drvPath, drv, options);
+    auto kont = conn.store->buildDerivationAsync(drvPath, drv, options);

    BuildResult result;

@@ -237,7 +132,10 @@ static BuildResult performBuild(
    startTime = time(0);
    {
        MaintainCount<counter> mc(nrStepsBuilding);
-        result = ServeProto::Serialise<BuildResult>::read(localStore, conn);
+        result = kont();
+        // Without proper call-once functions, we need to manually
+        // delete after calling.
+        kont = {};
    }
    stopTime = time(0);

@@ -253,7 +151,7 @@ static BuildResult performBuild(

    // If the protocol was too old to give us `builtOutputs`, initialize
    // it manually by introspecting the derivation.
-    if (GET_PROTOCOL_MINOR(conn.remoteVersion) < 6)
+    if (GET_PROTOCOL_MINOR(conn.store->getProtocol()) < 6)
    {
        // If the remote is too old to handle CA derivations, we can’t get this
        // far anyways
@@ -278,81 +176,6 @@ static BuildResult performBuild(
    return result;
 }

-static std::map<StorePath, UnkeyedValidPathInfo> queryPathInfos(
-    ::Machine::Connection & conn,
-    Store & localStore,
-    StorePathSet & outputs,
-    size_t & totalNarSize
-)
-{
-
-    /* Get info about each output path. */
-    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 storePath = localStore.parseStorePath(storePathS);
-        auto info = ServeProto::Serialise<UnkeyedValidPathInfo>::read(localStore, conn);
-        totalNarSize += info.narSize;
-        infos.insert_or_assign(std::move(storePath), std::move(info));
-    }
-
-    return infos;
-}
-
-static void copyPathFromRemote(
-    ::Machine::Connection & conn,
-    NarMemberDatas & narMembers,
-    Store & localStore,
-    Store & destStore,
-    const ValidPathInfo & info
-)
-{
-      /* Receive the NAR from the remote and add it to the
-          destination store. Meanwhile, extract all the info from the
-          NAR that getBuildOutput() needs. */
-      auto source2 = sinkToSource([&](Sink & sink)
-      {
-          /* Note: we should only send the command to dump the store
-              path to the remote if the NAR is actually going to get read
-              by the destination store, which won't happen if this path
-              is already valid on the destination store. Since this
-              lambda function only gets executed if someone tries to read
-              from source2, we will send the command from here rather
-              than outside the lambda. */
-          conn.to << ServeProto::Command::DumpStorePath << localStore.printStorePath(info.path);
-          conn.to.flush();
-
-          TeeSource tee(conn.from, sink);
-          extractNarData(tee, localStore.printStorePath(info.path), narMembers);
-      });
-
-      destStore.addToStore(info, *source2, NoRepair, NoCheckSigs);
-}
-
-static void copyPathsFromRemote(
-    ::Machine::Connection & conn,
-    NarMemberDatas & narMembers,
-    Store & localStore,
-    Store & destStore,
-    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,
-              ValidPathInfo { path, info });
-      }
-
-}
-
 }

 /* using namespace nix::build_remote; */
@@ -430,22 +253,39 @@ void State::buildRemote(ref<Store> destStore,

        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.
-        auto child = build_remote::openConnection(machine, master);
+        ::Machine::Connection conn {
+            .machine = machine,
+            .store = [&]{
+                auto * pSpecified = std::get_if<StoreReference::Specified>(&machine->storeUri.variant);
+                if (!pSpecified || pSpecified->scheme != "ssh") {
+                    throw Error("Currently, only (legacy-)ssh stores are supported!");
+                }
+
+                auto remoteStore = machine->openStore().dynamic_pointer_cast<LegacySSHStore>();
+                assert(remoteStore);
+
+                remoteStore->connPipeSize = 1024 * 1024;
+
+                if (machine->isLocalhost()) {
+                    auto rp_new = remoteStore->remoteProgram.get();
+                    rp_new.push_back("--builders");
+                    rp_new.push_back("");
+                    const_cast<nix::Setting<Strings> &>(remoteStore->remoteProgram).assign(rp_new);
+                }
+                remoteStore->extraSshArgs = {
+                    "-a", "-oBatchMode=yes", "-oConnectTimeout=60", "-oTCPKeepAlive=yes"
+                };
+                const_cast<nix::Setting<int> &>(remoteStore->logFD).assign(logFD.get());
+
+                return nix::ref{remoteStore};
+            }(),
+        };

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

        Finally clearPid([&]() {
@@ -460,41 +300,12 @@ void State::buildRemote(ref<Store> destStore,
               process. Meh. */
        });

-        ::Machine::Connection conn {
-            {
-                .to = child->in.get(),
-                .from = child->out.get(),
-                /* Handshake. */
-                .remoteVersion = 0xdadbeef, // FIXME avoid dummy initialize
-            },
-            /*.machine =*/ machine,
-        };
-
        Finally updateStats([&]() {
-            bytesReceived += conn.from.read;
-            bytesSent += conn.to.written;
+            auto stats = conn.store->getConnectionStats();
+            bytesReceived += stats.bytesReceived;
+            bytesSent += stats.bytesSent;
        });

-        constexpr ServeProto::Version our_version = 0x206;
-
-        try {
-            conn.remoteVersion = decltype(conn)::handshake(
-                conn.to,
-                conn.from,
-                our_version,
-                machine->sshName);
-        } catch (EndOfFile & e) {
-            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;
@@ -523,7 +334,7 @@ void State::buildRemote(ref<Store> destStore,
        /* Do the build. */
        printMsg(lvlDebug, "building ‘%s’ on ‘%s’",
            localStore->printStorePath(step->drvPath),
-            machine->sshName);
+            machine->storeUri.render());

        updateStep(ssBuilding);

@@ -546,7 +357,7 @@ void State::buildRemote(ref<Store> destStore,
           get a build log. */
        if (result.isCached) {
            printMsg(lvlInfo, "outputs of ‘%s’ substituted or already valid on ‘%s’",
-                localStore->printStorePath(step->drvPath), machine->sshName);
+                localStore->printStorePath(step->drvPath), machine->storeUri.render());
            unlink(result.logFile.c_str());
            result.logFile = "";
        }
@@ -563,19 +374,12 @@ void State::buildRemote(ref<Store> destStore,

            auto now1 = std::chrono::steady_clock::now();

-            size_t totalNarSize = 0;
-            auto infos = build_remote::queryPathInfos(conn, *localStore, outputs, totalNarSize);
-
-            if (totalNarSize > maxOutputSize) {
-                result.stepStatus = bsNarSizeLimitExceeded;
-                return;
-            }
-
            /* Copy each path. */
-            printMsg(lvlDebug, "copying outputs of ‘%s’ from ‘%s’ (%d bytes)",
-                localStore->printStorePath(step->drvPath), machine->sshName, totalNarSize);
+            printMsg(lvlDebug, "copying outputs of ‘%s’ from ‘%s’",
+                localStore->printStorePath(step->drvPath), machine->storeUri.render());
+
+            copyClosure(*conn.store, *destStore, outputs);

-            build_remote::copyPathsFromRemote(conn, narMembers, *localStore, *destStore, infos);
            auto now2 = std::chrono::steady_clock::now();

            result.overhead += std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();
@@ -596,9 +400,11 @@ void State::buildRemote(ref<Store> destStore,
            }
        }

-        /* Shut down the connection. */
-        child->in = -1;
-        child->sshPid.wait();
+        /* Shut down the connection done by RAII.
+
+           Only difference is kill() instead of wait() (i.e. send signal
+           then wait())
+         */

    } catch (Error & e) {
        /* Disable this machine until a certain period of time has
@@ -612,7 +418,7 @@ void State::buildRemote(ref<Store> destStore,
            info->consecutiveFailures = std::min(info->consecutiveFailures + 1, (unsigned int) 4);
            info->lastFailure = now;
            int delta = retryInterval * std::pow(retryBackoff, info->consecutiveFailures - 1) + (rand() % 30);
-            printMsg(lvlInfo, "will disable machine ‘%1%’ for %2%s", machine->sshName, delta);
+            printMsg(lvlInfo, "will disable machine ‘%1%’ for %2%s", machine->storeUri.render(), delta);
            info->disabledUntil = now + std::chrono::seconds(delta);
        }
        throw;
--- a/src/hydra-queue-runner/builder.cc
+++ b/src/hydra-queue-runner/builder.cc
@@ -41,7 +41,7 @@ void State::builder(MachineReservation::ptr reservation)
        } catch (std::exception & e) {
            printMsg(lvlError, "uncaught exception building ‘%s’ on ‘%s’: %s",
                localStore->printStorePath(reservation->step->drvPath),
-                reservation->machine->sshName,
+                reservation->machine->storeUri.render(),
                e.what());
        }
    }
@@ -150,7 +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.nrRepeats + 1, machine->sshName, buildId, (dependents.size() - 1));
+            localStore->printStorePath(step->drvPath), buildOptions.nrRepeats + 1, machine->storeUri.render(), buildId, (dependents.size() - 1));
    }

    if (!buildOneDone)
@@ -178,7 +178,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
                    unlink(result.logFile.c_str());
                }
            } catch (...) {
-                ignoreException();
+                ignoreExceptionInDestructor();
            }
        }
    });
@@ -196,7 +196,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
        {
            auto mc = startDbUpdate();
            pqxx::work txn(*conn);
-            stepNr = createBuildStep(txn, result.startTime, buildId, step, machine->sshName, bsBusy);
+            stepNr = createBuildStep(txn, result.startTime, buildId, step, machine->storeUri.render(), bsBusy);
            txn.commit();
        }

@@ -253,7 +253,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
    /* Finish the step in the database. */
    if (stepNr) {
        pqxx::work txn(*conn);
-        finishBuildStep(txn, result, buildId, stepNr, machine->sshName);
+        finishBuildStep(txn, result, buildId, stepNr, machine->storeUri.render());
        txn.commit();
    }

@@ -261,7 +261,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
       issue). Retry a number of times. */
    if (result.canRetry) {
        printMsg(lvlError, "possibly transient failure building ‘%s’ on ‘%s’: %s",
-            localStore->printStorePath(step->drvPath), machine->sshName, result.errorMsg);
+            localStore->printStorePath(step->drvPath), machine->storeUri.render(), result.errorMsg);
        assert(stepNr);
        bool retry;
        {
@@ -452,7 +452,7 @@ void State::failStep(
                    build->finishedInDB)
                    continue;
                createBuildStep(txn,
-                    0, build->id, step, machine ? machine->sshName : "",
+                    0, build->id, step, machine ? machine->storeUri.render() : "",
                    result.stepStatus, result.errorMsg, buildId == build->id ? 0 : 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"

@@ -255,7 +256,7 @@ system_time State::doDispatch()
                /* Can this machine do this step? */
                if (!mi.machine->supportsStep(step)) {
                    debug("machine '%s' does not support step '%s' (system type '%s')",
-                        mi.machine->sshName, localStore->printStorePath(step->drvPath), step->drv->platform);
+                        mi.machine->storeUri.render(), localStore->printStorePath(step->drvPath), step->drv->platform);
                    continue;
                }

--- a/src/hydra-queue-runner/hydra-queue-runner.cc
+++ b/src/hydra-queue-runner/hydra-queue-runner.cc
@@ -135,65 +135,26 @@ void State::parseMachines(const std::string & contents)
        oldMachines = *machines_;
    }

-    for (auto line : tokenizeString<Strings>(contents, "\n")) {
-        line = trim(std::string(line, 0, line.find('#')));
-        auto tokens = tokenizeString<std::vector<std::string>>(line);
-        if (tokens.size() < 3) continue;
-        tokens.resize(8);
-
-        if (tokens[5] == "-") tokens[5] = "";
-        auto supportedFeatures = tokenizeString<StringSet>(tokens[5], ",");
-
-        if (tokens[6] == "-") tokens[6] = "";
-        auto mandatoryFeatures = tokenizeString<StringSet>(tokens[6], ",");
-
-        for (auto & f : mandatoryFeatures)
-            supportedFeatures.insert(f);
-
-        using MaxJobs = std::remove_const<decltype(nix::Machine::maxJobs)>::type;
-
-        auto machine = std::make_shared<::Machine>(nix::Machine {
-            // `storeUri`, not yet used
-            "",
-            // `systemTypes`
-            tokenizeString<StringSet>(tokens[1], ","),
-            // `sshKey`
-            tokens[2] == "-" ? "" : tokens[2],
-            // `maxJobs`
-            tokens[3] != ""
-                ? string2Int<MaxJobs>(tokens[3]).value()
-                : 1,
-            // `speedFactor`
-            std::stof(tokens[4].c_str()),
-            // `supportedFeatures`
-            std::move(supportedFeatures),
-            // `mandatoryFeatures`
-            std::move(mandatoryFeatures),
-            // `sshPublicHostKey`
-            tokens[7] != "" && tokens[7] != "-"
-                ? base64Decode(tokens[7])
-                : "",
-        });
-
-        machine->sshName = tokens[0];
+    for (auto && machine_ : nix::Machine::parseConfig({}, contents)) {
+        auto machine = std::make_shared<::Machine>(std::move(machine_));

        /* Re-use the State object of the previous machine with the
           same name. */
-        auto i = oldMachines.find(machine->sshName);
+        auto i = oldMachines.find(machine->storeUri.variant);
        if (i == oldMachines.end())
-            printMsg(lvlChatty, "adding new machine ‘%1%’", machine->sshName);
+            printMsg(lvlChatty, "adding new machine ‘%1%’", machine->storeUri.render());
        else
-            printMsg(lvlChatty, "updating machine ‘%1%’", machine->sshName);
+            printMsg(lvlChatty, "updating machine ‘%1%’", machine->storeUri.render());
        machine->state = i == oldMachines.end()
            ? std::make_shared<::Machine::State>()
            : i->second->state;
-        newMachines[machine->sshName] = machine;
+        newMachines[machine->storeUri.variant] = machine;
    }

    for (auto & m : oldMachines)
        if (newMachines.find(m.first) == newMachines.end()) {
            if (m.second->enabled)
-                printInfo("removing machine ‘%1%’", m.first);
+                printInfo("removing machine ‘%1%’", m.second->storeUri.render());
            /* Add a disabled ::Machine object to make sure stats are
               maintained. */
            auto machine = std::make_shared<::Machine>(*(m.second));
@@ -657,7 +618,7 @@ void State::dumpStatus(Connection & conn)
                    machine["avgStepTime"] = (float) s->totalStepTime / s->nrStepsDone;
                    machine["avgStepBuildTime"] = (float) s->totalStepBuildTime / s->nrStepsDone;
                }
-                statusJson["machines"][m->sshName] = machine;
+                statusJson["machines"][m->storeUri.render()] = machine;
            }
        }

--- 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
@@ -54,32 +54,40 @@ struct Extractor : FileSystemObjectSink
    };

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

-    void createSymlink(const Path & path, const std::string & target) override
+    void createSymlink(const CanonPath & path, const std::string & target) override
    {
-        members.insert_or_assign(prefix + path, NarMemberData { .type = SourceAccessor::Type::tSymlink });
+        members.insert_or_assign(toKey(path), NarMemberData { .type = SourceAccessor::Type::tSymlink });
    }
 };

--- a/src/hydra-queue-runner/state.hh
+++ b/src/hydra-queue-runner/state.hh
@@ -6,7 +6,6 @@
 #include <map>
 #include <memory>
 #include <queue>
-#include <regex>

 #include <prometheus/counter.h>
 #include <prometheus/gauge.h>
@@ -21,8 +20,7 @@
 #include "store-api.hh"
 #include "sync.hh"
 #include "nar-extractor.hh"
-#include "serve-protocol.hh"
-#include "serve-protocol-impl.hh"
+#include "legacy-ssh-store.hh"
 #include "machines.hh"


@@ -240,10 +238,6 @@ struct Machine : nix::Machine
 {
    typedef std::shared_ptr<Machine> ptr;

-    /* TODO Get rid of: `nix::Machine::storeUri` is normalized in a way
-       we are not yet used to, but once we are, we don't need this. */
-    std::string sshName;
-
    struct State {
        typedef std::shared_ptr<State> ptr;
        counter currentJobs{0};
@@ -293,16 +287,14 @@ struct Machine : nix::Machine
        return true;
    }

-    bool isLocalhost()
-    {
-        std::regex r("^(ssh://|ssh-ng://)?localhost$");
-        return std::regex_search(sshName, r);
-    }
+    bool isLocalhost() const;

    // A connection to a machine
-    struct Connection : nix::ServeProto::BasicClientConnection {
+    struct Connection {
        // Backpointer to the machine
        ptr machine;
+        // Opened store
+        nix::ref<nix::LegacySSHStore> store;
    };
 };

@@ -357,7 +349,7 @@ private:

    /* The build machines. */
    std::mutex machinesReadyLock;
-    typedef std::map<std::string, Machine::ptr> Machines;
+    typedef std::map<nix::StoreReference::Variant, Machine::ptr> Machines;
    nix::Sync<Machines> machines; // FIXME: use atomic_shared_ptr

    /* Various stats. */
--- a/src/lib/Hydra/Controller/Root.pm
+++ b/src/lib/Hydra/Controller/Root.pm
@@ -51,6 +51,7 @@ sub begin :Private {
    $c->stash->{curUri} = $c->request->uri;
    $c->stash->{version} = $ENV{"HYDRA_RELEASE"} || "<devel>";
    $c->stash->{nixVersion} = $ENV{"NIX_RELEASE"} || "<devel>";
+    $c->stash->{nixEvalJobsVersion} = $ENV{"NIX_EVAL_JOBS_RELEASE"} || "<devel>";
    $c->stash->{curTime} = time;
    $c->stash->{logo} = defined $c->config->{hydra_logo} ? "/logo" : "";
    $c->stash->{tracker} = defined $c->config->{tracker} ? $c->config->{tracker} : "";
@@ -330,7 +331,7 @@ 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;
--- 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
@@ -46,7 +46,7 @@ sub fetchInput {

    $MACHINE_LOCAL_STORE->addTempRoot($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 {
--- 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 +1,85 @@
+# Native code
+subdir('libhydra')
+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/layout.tt
+++ b/src/root/layout.tt
@@ -93,7 +93,7 @@
      <footer class="navbar">
        <hr />
        <small>
-          <em><a href="http://nixos.org/hydra" target="_blank" class="squiggle">Hydra</a> [% HTML.escape(version) %] (using [% HTML.escape(nixVersion) %]).</em>
+          <em><a href="http://nixos.org/hydra" target="_blank" class="squiggle">Hydra</a> [% HTML.escape(version) %] (using [% HTML.escape(nixVersion) %] and [% HTML.escape(nixEvalJobsVersion) %]).</em>
          [% IF c.user_exists %]
          You are signed in as <tt>[% HTML.escape(c.user.username) %]</tt>
            [%- IF c.user.type == 'google' %] via Google[% 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/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
@@ -17,6 +17,7 @@ use Hydra::Helper::Nix;
 use Hydra::Model::DB;
 use Hydra::Plugin;
 use Hydra::Schema;
+use IPC::Run;
 use JSON::MaybeXS;
 use Net::Statsd;
 use Nix::Store;
@@ -357,22 +358,32 @@ sub evalJobs {
    my @cmd;

    if (defined $flakeRef) {
-        @cmd = ("hydra-eval-jobs",
-                "--flake", $flakeRef,
-                "--gc-roots-dir", getGCRootsDir,
-                "--max-jobs", 1);
+        my $nix_expr =
+            "let " .
+            "flake = builtins.getFlake (toString \"$flakeRef\"); " .
+            "in " .
+            "flake.hydraJobs " .
+            "or flake.checks " .
+            "or (throw \"flake '$flakeRef' does not provide any Hydra jobs or checks\")";
+
+        @cmd = ("nix-eval-jobs", "--expr", $nix_expr);
    } else {
        my $nixExprInput = $inputInfo->{$nixExprInputName}->[0]
            or die "cannot find the input containing the job expression\n";

-        @cmd = ("hydra-eval-jobs",
+        @cmd = ("nix-eval-jobs",
                "<" . $nixExprInputName . "/" . $nixExprPath . ">",
-                "--gc-roots-dir", getGCRootsDir,
-                "--max-jobs", 1,
                inputsToArgs($inputInfo));
    }

-    push @cmd, "--no-allow-import-from-derivation" if $config->{allow_import_from_derivation} // "true" ne "true";
+    push @cmd, ("--gc-roots-dir", getGCRootsDir);
+    push @cmd, ("--max-jobs", 1);
+    push @cmd, "--meta";
+    push @cmd, "--constituents";
+    push @cmd, "--force-recurse";
+    push @cmd, ("--option", "allow-import-from-derivation", "false") if $config->{allow_import_from_derivation} // "true" ne "true";
+    push @cmd, ("--workers", $config->{evaluator_workers} // 1);
+    push @cmd, ("--max-memory-size", $config->{evaluator_max_memory_size} // 4096);

    if (defined $ENV{'HYDRA_DEBUG'}) {
        sub escape {
@@ -384,14 +395,40 @@ sub evalJobs {
        print STDERR "evaluator: @escaped\n";
    }

-    (my $res, my $jobsJSON, my $stderr) = captureStdoutStderr(21600, @cmd);
-    die "hydra-eval-jobs returned " . ($res & 127 ? "signal $res" : "exit code " . ($res >> 8))
-        . ":\n" . ($stderr ? decode("utf-8", $stderr) : "(no output)\n")
-        if $res;
+    my $evalProc = IPC::Run::start \@cmd,
+            '>', IPC::Run::new_chunker, \my $out,
+            '2>', \my $err;

-    print STDERR "$stderr";
+    return sub {
+        while (1) {
+            $evalProc->pump;
+            if (!defined $out && !defined $err) {
+                $evalProc->finish;
+                if ($?) {
+                    die "nix-eval-jobs returned " . ($? & 127 ? "signal $?" : "exit code " . ($? >> 8)) . "\n";
+                }
+                return;
+            }

-    return decode_json($jobsJSON);
+            if (defined $err) {
+                print STDERR "$err";
+                undef $err;
+            }
+
+            if (defined $out && $out ne '') {
+                my $job;
+                try {
+                    $job = decode_json($out);
+                } catch {
+                    warn "nix-eval-jobs sent invalid JSON.\n  parse error: $_\n  invalid json: $out\n";
+                };
+                undef $out;
+                if (defined $job) {
+                    return $job;
+                }
+            }
+        }
+    };
 }


@@ -420,7 +457,7 @@ sub checkBuild {
    my $firstOutputName = $outputNames[0];
    my $firstOutputPath = $buildInfo->{outputs}->{$firstOutputName};

-    my $jobName = $buildInfo->{jobName} or die;
+    my $jobName = $buildInfo->{attr} or die;
    my $drvPath = $buildInfo->{drvPath} or die;

    my $build;
@@ -474,9 +511,30 @@ sub checkBuild {

        my $time = time();

-        sub null {
-            my ($s) = @_;
-            return $s eq "" ? undef : $s;
+        sub getMeta {
+            my ($s, $def) = @_;
+            return ($s || "") eq "" ? $def : $s;
+        }
+
+        sub getMetaStrings {
+            my ($v, $k, $acc) = @_;
+            my $t = ref $v;
+
+            if ($t eq 'HASH') {
+                push @$acc, $v->{$k} if exists $v->{$k};
+            } elsif ($t eq 'ARRAY') {
+                getMetaStrings($_, $k, $acc) foreach @$v;
+            } elsif (defined $v) {
+                push @$acc, $v;
+            }
+        }
+
+        sub getMetaConcatStrings {
+            my ($v, $k) = @_;
+
+            my @strings;
+            getMetaStrings($v, $k, \@strings);
+            return join(", ", @strings) || undef;
        }

        # Add the build to the database.
@@ -484,19 +542,19 @@ sub checkBuild {
            { timestamp => $time
            , jobset_id => $jobset->id
            , job => $jobName
-            , description => null($buildInfo->{description})
-            , license => null($buildInfo->{license})
-            , homepage => null($buildInfo->{homepage})
-            , maintainers => null($buildInfo->{maintainers})
-            , maxsilent => $buildInfo->{maxSilent}
-            , timeout => $buildInfo->{timeout}
-            , nixname => $buildInfo->{nixName}
+            , description => getMeta($buildInfo->{meta}->{description}, undef)
+            , license => getMetaConcatStrings($buildInfo->{meta}->{license}, "shortName")
+            , homepage => getMeta($buildInfo->{meta}->{homepage}, undef)
+            , maintainers => getMetaConcatStrings($buildInfo->{meta}->{maintainers}, "email")
+            , maxsilent => getMeta($buildInfo->{meta}->{maxSilent}, 7200)
+            , timeout => getMeta($buildInfo->{meta}->{timeout}, 36000)
+            , nixname => $buildInfo->{name}
            , drvpath => $drvPath
            , system => $buildInfo->{system}
-            , priority => $buildInfo->{schedulingPriority}
+            , priority => getMeta($buildInfo->{meta}->{schedulingPriority}, 100)
            , finished => 0
            , iscurrent => 1
-            , ischannel => $buildInfo->{isChannel}
+            , ischannel => getMeta($buildInfo->{meta}->{isChannel}, 0)
            });

        $build->buildoutputs->create({ name => $_, path => $buildInfo->{outputs}->{$_} })
@@ -665,7 +723,7 @@ sub checkJobsetWrapped {
        return;
    }

-    # Hash the arguments to hydra-eval-jobs and check the
+    # Hash the arguments to nix-eval-jobs and check the
    # JobsetInputHashes to see if the previous evaluation had the same
    # inputs.  If so, bail out.
    my @args = ($jobset->nixexprinput // "", $jobset->nixexprpath // "", inputsToArgs($inputInfo));
@@ -687,19 +745,12 @@ sub checkJobsetWrapped {

    # Evaluate the job expression.
    my $evalStart = clock_gettime(CLOCK_MONOTONIC);
-    my $jobs = evalJobs($project->name . ":" . $jobset->name, $inputInfo, $jobset->nixexprinput, $jobset->nixexprpath, $flakeRef);
-    my $evalStop = clock_gettime(CLOCK_MONOTONIC);
-
-    if ($jobsetsJobset) {
-        my @keys = keys %$jobs;
-        die "The .jobsets jobset must only have a single job named 'jobsets'"
-            unless (scalar @keys) == 1 && $keys[0] eq "jobsets";
-    }
-    Net::Statsd::timing("hydra.evaluator.eval_time", int(($evalStop - $evalStart) * 1000));
+    my $evalStop;
+    my $jobsIter = evalJobs($project->name . ":" . $jobset->name, $inputInfo, $jobset->nixexprinput, $jobset->nixexprpath, $flakeRef);

    if ($dryRun) {
-        foreach my $name (keys %{$jobs}) {
-            my $job = $jobs->{$name};
+        while (defined(my $job = $jobsIter->())) {
+            my $name = $job->{attr};
            if (defined $job->{drvPath}) {
                print STDERR "good job $name: $job->{drvPath}\n";
            } else {
@@ -709,36 +760,20 @@ sub checkJobsetWrapped {
        return;
    }

-    die "Jobset contains a job with an empty name. Make sure the jobset evaluates to an attrset of jobs.\n"
-        if defined $jobs->{""};
-
-    $jobs->{$_}->{jobName} = $_ for keys %{$jobs};
-
-    my $jobOutPathMap = {};
-    my $jobsetChanged = 0;
-    my $dbStart = clock_gettime(CLOCK_MONOTONIC);
-
-
    # Store the error messages for jobs that failed to evaluate.
    my $evaluationErrorTime = time;
    my $evaluationErrorMsg = "";
-    foreach my $job (values %{$jobs}) {
-        next unless defined $job->{error};
-        $evaluationErrorMsg .=
-            ($job->{jobName} ne "" ? "in job ‘$job->{jobName}’" : "at top-level") .
-            ":\n" . $job->{error} . "\n\n";
-    }
-    setJobsetError($jobset, $evaluationErrorMsg, $evaluationErrorTime);
-
    my $evaluationErrorRecord = $db->resultset('EvaluationErrors')->create(
        { errormsg => $evaluationErrorMsg
        , errortime => $evaluationErrorTime
        }
    );

+    my $jobOutPathMap = {};
+    my $jobsetChanged = 0;
    my %buildMap;
-    $db->txn_do(sub {

+    $db->txn_do(sub {
        my $prevEval = getPrevJobsetEval($db, $jobset, 1);

        # Clear the "current" flag on all builds.  Since we're in a
@@ -751,7 +786,7 @@ sub checkJobsetWrapped {
            , evaluationerror => $evaluationErrorRecord
            , timestamp => time
            , checkouttime => abs(int($checkoutStop - $checkoutStart))
-            , evaltime => abs(int($evalStop - $evalStart))
+            , evaltime => 0
            , hasnewbuilds => 0
            , nrbuilds => 0
            , flake => $flakeRef
@@ -759,11 +794,24 @@ sub checkJobsetWrapped {
            , nixexprpath => $jobset->nixexprpath
            });

-        # Schedule each successfully evaluated job.
-        foreach my $job (permute(values %{$jobs})) {
-            next if defined $job->{error};
-            #print STDERR "considering job " . $project->name, ":", $jobset->name, ":", $job->{jobName} . "\n";
-            checkBuild($db, $jobset, $ev, $inputInfo, $job, \%buildMap, $prevEval, $jobOutPathMap, $plugins);
+        my @jobsWithConstituents;
+
+        while (defined(my $job = $jobsIter->())) {
+            if ($jobsetsJobset) {
+                die "The .jobsets jobset must only have a single job named 'jobsets'"
+                    unless $job->{attr} eq "jobsets";
+            }
+
+            $evaluationErrorMsg .=
+                ($job->{attr} ne "" ? "in job ‘$job->{attr}’" : "at top-level") .
+                ":\n" . $job->{error} . "\n\n" if defined $job->{error};
+
+            checkBuild($db, $jobset, $ev, $inputInfo, $job, \%buildMap, $prevEval, $jobOutPathMap, $plugins)
+                unless defined $job->{error};
+
+            if (defined $job->{constituents}) {
+                push @jobsWithConstituents, $job;
+            }
        }

        # Have any builds been added or removed since last time?
@@ -801,21 +849,20 @@ sub checkJobsetWrapped {
                $drvPathToId{$x->{drvPath}} = $x;
            }

-            foreach my $job (values %{$jobs}) {
-                next unless $job->{constituents};
-
+            foreach my $job (values @jobsWithConstituents) {
+                next unless defined $job->{constituents};
                if (defined $job->{error}) {
-                    die "aggregate job ‘$job->{jobName}’ failed with the error: $job->{error}\n";
+                    die "aggregate job ‘$job->{attr}’ failed with the error: $job->{error}\n";
                }

                my $x = $drvPathToId{$job->{drvPath}} or
-                    die "aggregate job ‘$job->{jobName}’ has no corresponding build record.\n";
+                    die "aggregate job ‘$job->{attr}’ has no corresponding build record.\n";
                foreach my $drvPath (@{$job->{constituents}}) {
                    my $constituent = $drvPathToId{$drvPath};
                    if (defined $constituent) {
                        $db->resultset('AggregateConstituents')->update_or_create({aggregate => $x->{id}, constituent => $constituent->{id}});
                    } else {
-                        warn "aggregate job ‘$job->{jobName}’ has a constituent ‘$drvPath’ that doesn't correspond to a Hydra build\n";
+                        warn "aggregate job ‘$job->{attr}’ has a constituent ‘$drvPath’ that doesn't correspond to a Hydra build\n";
                    }
                }
            }
@@ -857,11 +904,15 @@ sub checkJobsetWrapped {
        $jobset->update({ enabled => 0 }) if $jobset->enabled == 2;

        $jobset->update({ lastcheckedtime => time, forceeval => undef });
+
+        $evaluationErrorRecord->update({ errormsg => $evaluationErrorMsg });
+        setJobsetError($jobset, $evaluationErrorMsg, $evaluationErrorTime);
+
+        $evalStop = clock_gettime(CLOCK_MONOTONIC);
+        $ev->update({ evaltime => abs(int($evalStop - $evalStart)) });
    });

-    my $dbStop = clock_gettime(CLOCK_MONOTONIC);
-
-    Net::Statsd::timing("hydra.evaluator.db_time", int(($dbStop - $dbStart) * 1000));
+    Net::Statsd::timing("hydra.evaluator.eval_time", int(($evalStop - $evalStart) * 1000));
    Net::Statsd::increment("hydra.evaluator.evals");
    Net::Statsd::increment("hydra.evaluator.cached_evals") unless $jobsetChanged;
 }
--- 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 = $(EXTRA_DIST)
--- a/src/ttf/meson.build
+++ b/src/ttf/meson.build
@@ -0,0 +1,5 @@
+data_files = files(
+  'StayPuft.ttf',
+  'COPYING.LIB',
+)
+install_data(data_files, install_dir: hydra_libexecdir / 'ttf')
--- a/t/Makefile.am
+++ b/t/Makefile.am
@@ -1,39 +0,0 @@
-TESTS_ENVIRONMENT = \
-  BZR_HOME="$(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) \
-  $(TESTS)
-
-TESTS = \
-  perlcritic.pl \
-  test.pl
-
-check_SCRIPTS = repos
-
-repos: dirs
-
-dirs:
-	mkdir -p data
-	touch data/hydra.conf
-	mkdir -p nix
-	mkdir -p nix/etc/nix
-	mkdir -p nix/store
-	mkdir -p nix/var
--- a/t/evaluator/evaluate-constituents-broken.t
+++ b/t/evaluator/evaluate-constituents-broken.t
@@ -18,14 +18,14 @@ isnt($res, 0, "hydra-eval-jobset exits non-zero");
 ok(utf8::decode($stderr), "Stderr output is UTF8-clean");
 like(
    $stderr,
-    qr/aggregate job ‘mixed_aggregate’ failed with the error: constituentA: does not exist/,
+    qr/aggregate job ‘mixed_aggregate’ failed with the error: "constituentA": does not exist/,
    "The stderr record includes a relevant error message"
 );

-$jobset->discard_changes;  # refresh from DB
+$jobset->discard_changes({ '+columns' => {'errormsg' => 'errormsg'} });  # refresh from DB
 like(
    $jobset->errormsg,
-    qr/aggregate job ‘mixed_aggregate’ failed with the error: constituentA: does not exist/,
+    qr/aggregate job ‘mixed_aggregate’ failed with the error: "constituentA": does not exist/,
    "The jobset records a relevant error message"
 );

--- a/t/evaluator/evaluate-constituents-gc.t
+++ b/t/evaluator/evaluate-constituents-gc.t
@@ -5,13 +5,58 @@ use Test2::V0;

 my $ctx = test_context();

-my $builds = $ctx->makeAndEvaluateJobset(
-    expression => 'constituents.nix',
+my $expression = 'constituents.nix';
+my $jobsetCtx = $ctx->makeJobset(
+    expression => $expression,
+);
+my $builds = $ctx->evaluateJobset(
+    jobset => $jobsetCtx->{"jobset"},
+    expression => $expression,
+    build => 0,
 );

 my $constituentA = $builds->{"constituentA"};
 my $directAggregate = $builds->{"direct_aggregate"};
 my $indirectAggregate = $builds->{"indirect_aggregate"};
+my $mixedAggregate = $builds->{"mixed_aggregate"};
+
+# Ensure that we get exactly the aggregates we expect
+my %expected_constituents = (
+    'direct_aggregate' => {
+        'constituentA' => 1,
+    },
+    'indirect_aggregate' => {
+        'constituentA' => 1,
+    },
+    'mixed_aggregate' => {
+        # Note that `constituentA_alias` becomes `constituentA`, because
+        # the shorter name is preferred
+        'constituentA' => 1,
+        'constituentB' => 1,
+    },
+);
+
+my $rs = $ctx->db->resultset('AggregateConstituents')->search(
+    {},
+    {
+        join     => [ 'aggregate', 'constituent' ],  # Use correct relationship names
+        columns  => [],
+        '+select' => [ 'aggregate.job', 'constituent.job' ],
+        '+as'     => [ 'aggregate_job', 'constituent_job' ],
+    }
+);
+
+my %actual_constituents;
+while (my $row = $rs->next) {
+    my $aggregate_job   = $row->get_column('aggregate_job');
+    my $constituent_job = $row->get_column('constituent_job');
+    $actual_constituents{$aggregate_job} //= {};
+    $actual_constituents{$aggregate_job}{$constituent_job} = 1;
+}
+
+is(\%actual_constituents, \%expected_constituents, "Exact aggregate constituents as expected");
+
+# Check that deletion also doesn't work accordingly

 is(system('nix-store', '--delete', $constituentA->drvpath), 256, "Deleting a constituent derivation fails");
 is(system('nix-store', '--delete', $directAggregate->drvpath), 256, "Deleting the direct aggregate derivation fails");
--- a/t/evaluator/evaluate-flake.t
+++ b/t/evaluator/evaluate-flake.t
@@ -0,0 +1,67 @@
+use feature 'unicode_strings';
+use strict;
+use warnings;
+use Setup;
+use Test2::V0;
+use File::Copy qw(cp);
+
+my $ctx = test_context(
+    nix_config => qq|
+    experimental-features = nix-command flakes
+    |,
+    hydra_config => q|
+    <runcommand>
+      evaluator_pure_eval = false
+    </runcommand>
+    |
+);
+
+sub checkFlake {
+    my ($flake) = @_;
+
+    cp($ctx->jobsdir . "/basic.nix", $ctx->jobsdir . "/" . $flake);
+    cp($ctx->jobsdir . "/config.nix", $ctx->jobsdir . "/" . $flake);
+    cp($ctx->jobsdir . "/empty-dir-builder.sh", $ctx->jobsdir . "/" . $flake);
+    cp($ctx->jobsdir . "/fail.sh", $ctx->jobsdir . "/" . $flake);
+    cp($ctx->jobsdir . "/succeed-with-failed.sh", $ctx->jobsdir . "/" . $flake);
+
+    chmod 0755, $ctx->jobsdir . "/" . $flake . "/empty-dir-builder.sh";
+    chmod 0755, $ctx->jobsdir . "/" . $flake . "/fail.sh";
+    chmod 0755, $ctx->jobsdir . "/" . $flake . "/succeed-with-failed.sh";
+
+    my $builds = $ctx->makeAndEvaluateJobset(
+        flake => 'path:' . $ctx->jobsdir . "/" . $flake,
+        build => 1
+    );
+
+    subtest "Build: succeed_with_failed" => sub {
+        my $build = $builds->{"succeed_with_failed"};
+
+        is($build->finished, 1, "Build should be finished.");
+        is($build->buildstatus, 6, "succeeeded-but-failed should have buildstatus 6.");
+    };
+
+    subtest "Build: empty_dir" => sub {
+        my $build = $builds->{"empty_dir"};
+
+        is($build->finished, 1, "Build should be finished.");
+        is($build->buildstatus, 0, "Should have succeeded.");
+    };
+
+    subtest "Build: fails" => sub {
+        my $build = $builds->{"fails"};
+
+        is($build->finished, 1, "Build should be finished.");
+        is($build->buildstatus, 1, "Should have failed.");
+    };
+}
+
+subtest "Flake using `checks`" => sub {
+    checkFlake 'flake-checks'
+};
+
+subtest "Flake using `hydraJobs`" => sub {
+    checkFlake 'flake-hydraJobs'
+};
+
+done_testing;
--- a/t/evaluator/evaluate-meta.t
+++ b/t/evaluator/evaluate-meta.t
@@ -0,0 +1,22 @@
+use feature 'unicode_strings';
+use strict;
+use warnings;
+use Setup;
+use Test2::V0;
+
+my $ctx = test_context();
+
+my $builds = $ctx->makeAndEvaluateJobset(
+    expression => "meta.nix",
+    build => 1
+);
+
+my $build = $builds->{"full-of-meta"};
+
+is($build->finished, 1, "Build should be finished.");
+is($build->description, "This is the description of the job.", "Wrong description extracted from the build.");
+is($build->license, "MIT, BSD", "Wrong licenses extracted from the build.");
+is($build->homepage, "https://example.com/", "Wrong homepage extracted from the build.");
+is($build->maintainers, 'alice@example.com, bob@not.found', "Wrong maintainers extracted from the build.");
+
+done_testing;
--- a/t/jobs/constituents.nix
+++ b/t/jobs/constituents.nix
@@ -5,6 +5,8 @@ rec {
    builder = ./empty-dir-builder.sh;
  };

+  constituentA_alias = constituentA;
+
  constituentB = mkDerivation {
    name = "empty-dir-B";
    builder = ./empty-dir-builder.sh;
@@ -32,7 +34,7 @@ rec {
    name = "mixed_aggregate";
    _hydraAggregate = true;
    constituents = [
-      "constituentA"
+      "constituentA_alias"
      constituentB
    ];
    builder = ./empty-dir-builder.sh;
--- a/t/jobs/flake-checks/flake.nix
+++ b/t/jobs/flake-checks/flake.nix
@@ -0,0 +1,6 @@
+{
+  outputs = { ... }: {
+    checks =
+      import ./basic.nix;
+  };
+}
--- a/t/jobs/flake-hydraJobs/flake.nix
+++ b/t/jobs/flake-hydraJobs/flake.nix
@@ -0,0 +1,6 @@
+{
+  outputs = { ... }: {
+    hydraJobs =
+      import ./basic.nix;
+  };
+}
--- a/t/jobs/meta.nix
+++ b/t/jobs/meta.nix
@@ -0,0 +1,17 @@
+with import ./config.nix;
+{
+  full-of-meta =
+    mkDerivation {
+      name = "full-of-meta";
+      builder = ./empty-dir-builder.sh;
+
+      meta = {
+        description = "This is the description of the job.";
+        license = [ { shortName = "MIT"; } "BSD" ];
+        homepage = "https://example.com/";
+        maintainers = [ "alice@example.com" { email = "bob@not.found"; } ];
+
+        outPath = "${placeholder "out"}";
+      };
+    };
+}
--- 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;

@@ -156,20 +165,46 @@ sub nix_state_dir {
 sub makeAndEvaluateJobset {
    my ($self, %opts) = @_;

-    my $expression = $opts{'expression'} || die "Mandatory 'expression' option not passed to makeAndEvaluateJobset.\n";
-    my $jobsdir = $opts{'jobsdir'} // $self->jobsdir;
-    my $should_build = $opts{'build'} // 0;
+    my $expression = $opts{'expression'};
+    my $flake = $opts{'flake'};
+    if (not $expression and not $flake) {
+        die "One of 'expression' or 'flake' must be passed to makeEvaluateJobset.\n";
+    }

-    my $jobsetCtx = $self->makeJobset(
-        expression => $expression,
+    my $jobsdir = $opts{'jobsdir'} // $self->jobsdir;
+
+    my %args = (
        jobsdir => $jobsdir,
    );
-    my $jobset = $jobsetCtx->{"jobset"};
+    if ($expression) {
+        $args{expression} = $expression;
+    }
+    if ($flake) {
+        $args{flake} = $flake;
+    }
+    my $jobsetCtx = $self->makeJobset(%args);
+
+    return $self->evaluateJobset(
+        jobset => $jobsetCtx->{"jobset"},
+        expression => $expression,
+        flake => $flake,
+        build => $opts{"build"} // 0,
+    )
+}
+
+sub evaluateJobset {
+    my ($self, %opts) = @_;
+
+    my $jobset = $opts{'jobset'};
+
+    my $expression = $opts{'expression'} // $opts{'flake'};

    evalSucceeds($jobset) or die "Evaluating jobs/$expression should exit with return code 0.\n";

    my $builds = {};

+    my $should_build = $opts{'build'};
+
    for my $build ($jobset->builds) {
        if ($should_build) {
            runBuild($build) or die "Build '".$build->job."' from jobs/$expression should exit with return code 0.\n";
@@ -186,7 +221,7 @@ sub makeAndEvaluateJobset {
 #
 # In return, you get a hash of the user, project, and jobset records.
 #
-# This always uses an `expression` from the `jobsdir` directory.
+# This always uses an `expression` or `flake` from the `jobsdir` directory.
 #
 # Hash Parameters:
 #
@@ -195,7 +230,12 @@ sub makeAndEvaluateJobset {
 sub makeJobset {
    my ($self, %opts) = @_;

-    my $expression = $opts{'expression'} || die "Mandatory 'expression' option not passed to makeJobset.\n";
+    my $expression = $opts{'expression'};
+    my $flake = $opts{'flake'};
+    if (not $expression and not $flake) {
+        die "One of 'expression' or 'flake' must be passed to makeJobset.\n";
+    }
+
    my $jobsdir = $opts{'jobsdir'} // $self->jobsdir;

    # Create a new user for this test
@@ -213,12 +253,20 @@ sub makeJobset {
    });

    # Create a new jobset for this test and set up the inputs
-    my $jobset = $project->jobsets->create({
+    my %args = (
        name => rand_chars(),
-        nixexprinput => "jobs",
-        nixexprpath => $expression,
        emailoverride => ""
-    });
+    );
+    if ($expression) {
+        $args{type} = 0;
+        $args{nixexprinput} = "jobs";
+        $args{nixexprpath} = $expression;
+    }
+    if ($flake) {
+        $args{type} = 1;
+        $args{flake} = $flake;
+    }
+    my $jobset = $project->jobsets->create(\%args);
    my $jobsetinput = $jobset->jobsetinputs->create({name => "jobs", type => "path"});
    $jobsetinput->jobsetinputalts->create({altnr => 0, value => $jobsdir});

@@ -243,6 +291,18 @@ 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 $line;
+    }
+}
+
 sub rand_chars {
    return sprintf("t%08X", rand(0xFFFFFFFF));
 }
--- a/t/meson.build
+++ b/t/meson.build
@@ -0,0 +1,43 @@
+fs = import('fs')
+
+test('perlcritic',
+  perl,
+  args: ['-w', files('perlcritic.pl')],
+  workdir: meson.project_source_root(),
+  timeout: -1,
+)
+
+testenv = environment(
+  {
+    'BZR_HOME': meson.current_build_dir() / 'data',
+    'HYDRA_DBI': 'dbi:Pg:dbname=hydra-test-suite;port=6433',
+    'HYDRA_DATA': meson.current_build_dir() / 'data',
+    'HYDRA_HOME': meson.project_source_root() / 'src',
+    'PGHOST': '/tmp',
+    'PYTHONPATH': '',
+
+    # libpqxx seems to randomly crash with certain values of MALLOC_PERTURB_,
+    # set by default by Meson's test(). Very promising, high quality software.
+    'MALLOC_PERTURB_': '0',
+  },
+)
+testenv.prepend('PERL5LIB',
+  meson.current_source_dir(),
+  meson.project_source_root() / 'src/lib',
+  separator: ':'
+)
+testenv.prepend('PATH',
+  fs.parent(find_program('nix').full_path()),
+  fs.parent(hydra_evaluator.full_path()),
+  fs.parent(hydra_queue_runner.full_path()),
+  meson.project_source_root() / 'src/script',
+  separator: ':'
+)
+
+test('testsuite',
+  perl,
+  args: ['-I', meson.current_source_dir() / 'lib', '-w', files('test.pl')],
+  env: testenv,
+  workdir: meson.current_source_dir(),
+  timeout: -1,
+)
--- a/t/queue-runner/constituents.t
+++ b/t/queue-runner/constituents.t
@@ -22,11 +22,11 @@ is(nrQueuedBuildsForJobset($jobset), 0, "Evaluating jobs/broken-constituent.nix

 like(
    $jobset->errormsg,
-    qr/^does-not-exist: does not exist$/m,
+    qr/^"does-not-exist": does not exist$/m,
    "Evaluating jobs/broken-constituent.nix should log an error for does-not-exist");
 like(
    $jobset->errormsg,
-    qr/^does-not-evaluate: error: assertion 'false' failed$/m,
+    qr/^"does-not-evaluate": "error: assertion 'false' failed/m,
    "Evaluating jobs/broken-constituent.nix should log an error for does-not-evaluate");

 done_testing;