WIP ssh-ng://

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).

flake.lock

@@ -1,51 +1,11 @@
 {
   "nodes": {
-    "flake-parts": {
-      "inputs": {
-        "nixpkgs-lib": [
-          "nix-eval-jobs",
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1722555600,
-        "narHash": "sha256-XOQkdLafnb/p9ij77byFQjDf5m5QYl9b2REiVClC+x4=",
-        "owner": "hercules-ci",
-        "repo": "flake-parts",
-        "rev": "8471fe90ad337a8074e957b69ca4d0089218391d",
-        "type": "github"
-      },
-      "original": {
-        "owner": "hercules-ci",
-        "repo": "flake-parts",
-        "type": "github"
-      }
-    },
-    "libgit2": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1715853528,
-        "narHash": "sha256-J2rCxTecyLbbDdsyBWn9w7r3pbKRMkI9E7RvRgAqBdY=",
-        "owner": "libgit2",
-        "repo": "libgit2",
-        "rev": "36f7e21ad757a3dacc58cf7944329da6bc1d6e96",
-        "type": "github"
-      },
-      "original": {
-        "owner": "libgit2",
-        "ref": "v1.8.1",
-        "repo": "libgit2",
-        "type": "github"
-      }
-    },
     "nix": {
       "inputs": {
         "flake-compat": [],
         "flake-parts": [],
         "git-hooks-nix": [],
-        "libgit2": [
-          "libgit2"
-        ],
+        "nixfmt": [],
         "nixpkgs": [
           "nixpkgs"
         ],
@@ -53,88 +13,59 @@
         "nixpkgs-regression": []
       },
       "locked": {
-        "lastModified": 1726787955,
-        "narHash": "sha256-XFznzb8L4SdUm9u+w3DPpMWJhffuv+/6+aiVl00slns=",
+        "lastModified": 1739571938,
+        "narHash": "sha256-NlaLAed/xei6RWpU2HIIbDjILRC4l1NIfGeyrn7ALQs=",
         "owner": "NixOS",
         "repo": "nix",
-        "rev": "a7fdef6858dd45b9d7bda7c92324c63faee7f509",
+        "rev": "ffc649d2eabdd3e678b5bcc211dd59fd06debf3e",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "2.24-maintenance",
+        "ref": "ssh-ng-extensions-for-hydra",
         "repo": "nix",
         "type": "github"
       }
     },
     "nix-eval-jobs": {
-      "inputs": {
-        "flake-parts": "flake-parts",
-        "nix-github-actions": [],
-        "nixpkgs": [
-          "nixpkgs"
-        ],
-        "treefmt-nix": "treefmt-nix"
-      },
+      "flake": false,
       "locked": {
-        "lastModified": 1733814344,
-        "narHash": "sha256-3wwtKpS5tUBdjaGeSia7CotonbiRB6K5Kp0dsUt3nzU=",
-        "owner": "nix-community",
+        "lastModified": 1739499741,
+        "narHash": "sha256-dNMJY6+G3PwE8lIAhwetPJdA2DxCEKRXPY/EtHmdDh4=",
+        "owner": "Ericson2314",
         "repo": "nix-eval-jobs",
-        "rev": "889ea1406736b53cf165b6c28398aae3969418d1",
+        "rev": "de345eb4518d952c2d86261b270f2c31edecd3de",
         "type": "github"
       },
       "original": {
-        "owner": "nix-community",
-        "ref": "release-2.24",
+        "owner": "Ericson2314",
+        "ref": "nix-2.27",
         "repo": "nix-eval-jobs",
         "type": "github"
       }
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1726688310,
-        "narHash": "sha256-Xc9lEtentPCEtxc/F1e6jIZsd4MPDYv4Kugl9WtXlz0=",
+        "lastModified": 1739461644,
+        "narHash": "sha256-1o1qR0KYozYGRrnqytSpAhVBYLNBHX+Lv6I39zGRzKM=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "dbebdd67a6006bb145d98c8debf9140ac7e651d0",
+        "rev": "97a719c9f0a07923c957cf51b20b329f9fb9d43f",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixos-24.05-small",
+        "ref": "nixos-24.11-small",
         "repo": "nixpkgs",
         "type": "github"
       }
     },
     "root": {
       "inputs": {
-        "libgit2": "libgit2",
         "nix": "nix",
         "nix-eval-jobs": "nix-eval-jobs",
         "nixpkgs": "nixpkgs"
       }
-    },
-    "treefmt-nix": {
-      "inputs": {
-        "nixpkgs": [
-          "nix-eval-jobs",
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1723303070,
-        "narHash": "sha256-krGNVA30yptyRonohQ+i9cnK+CfCpedg6z3qzqVJcTs=",
-        "owner": "numtide",
-        "repo": "treefmt-nix",
-        "rev": "14c092e0326de759e16b37535161b3cb9770cea3",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "treefmt-nix",
-        "type": "github"
-      }
     }
   },
   "root": "root",

flake.nix

@@ -1,25 +1,26 @@
 {
   description = "A Nix-based continuous build system";
 
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05-small";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11-small";
 
-  inputs.libgit2 = { url = "github:libgit2/libgit2/v1.8.1"; flake = false; };
-  inputs.nix.url = "github:NixOS/nix/2.24-maintenance";
-  inputs.nix.inputs.nixpkgs.follows = "nixpkgs";
-  inputs.nix.inputs.libgit2.follows = "libgit2";
+  inputs.nix = {
+    url = "github:NixOS/nix/ssh-ng-extensions-for-hydra";
+    inputs.nixpkgs.follows = "nixpkgs";
 
-  inputs.nix-eval-jobs.url = "github:nix-community/nix-eval-jobs/release-2.24";
-  inputs.nix-eval-jobs.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.nixfmt.follows = "";
+  };
 
-  # hide nix dev tooling from our lock file
-  inputs.nix.inputs.flake-parts.follows = "";
-  inputs.nix.inputs.git-hooks-nix.follows = "";
-  inputs.nix.inputs.nixpkgs-regression.follows = "";
-  inputs.nix.inputs.nixpkgs-23-11.follows = "";
-  inputs.nix.inputs.flake-compat.follows = "";
-
-  # hide nix-eval-jobs dev tooling from our lock file
-  inputs.nix-eval-jobs.inputs.nix-github-actions.follows = "";
+  inputs.nix-eval-jobs = {
+    url = "github:Ericson2314/nix-eval-jobs/nix-2.27";
+    # We want to control the deps precisely
+    flake = false;
+  };
 
   outputs = { self, nixpkgs, nix, nix-eval-jobs, ... }:
     let
@@ -30,9 +31,9 @@
 
       # 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;
-          nix-eval-jobs = nix-eval-jobs.packages.${final.system}.default;
           rawSrc = self;
           nix-perl-bindings = final.nixComponents.nix-perl-bindings;
         };
@@ -74,11 +75,19 @@
       });
 
       packages = forEachSystem (system: {
+        nix-eval-jobs = nixpkgs.legacyPackages.${system}.callPackage nix-eval-jobs {
+          nix = nix.packages.${system}.nix;
+        };
         hydra = nixpkgs.legacyPackages.${system}.callPackage ./package.nix {
           inherit (nixpkgs.lib) fileset;
-          nix-eval-jobs = nix-eval-jobs.packages.${system}.default;
+          inherit (self.packages.${system}) nix-eval-jobs;
           rawSrc = self;
-          nix = nix.packages.${system}.nix;
+          inherit (nix.packages.${system})
+            nix-util
+            nix-store
+            nix-main
+            nix-cli
+            ;
           nix-perl-bindings = nix.hydraJobs.perlBindings.${system};
         };
         default = self.packages.${system}.hydra;

meson.build

@@ -8,22 +8,22 @@ project('hydra', 'cpp',
   ],
 )
 
+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_expr_dep = dependency('nix-expr', required: true)
-nix_flake_dep = dependency('nix-flake', required: true)
-nix_cmd_dep = dependency('nix-cmd', required: true)
 
 # Nix need extra flags not provided in its pkg-config files.
 nix_dep = declare_dependency(
   dependencies: [
+    nix_util_dep,
     nix_store_dep,
     nix_main_dep,
-    nix_expr_dep,
-    nix_flake_dep,
-    nix_cmd_dep,
   ],
-  compile_args: ['-include', 'nix/config.h'],
+  compile_args: [
+    '-include', 'nix/config-util.hh',
+    '-include', 'nix/config-store.hh',
+    '-include', 'nix/config-main.hh',
+  ],
 )
 
 pqxx_dep = dependency('libpqxx', required: true)

package.nix

@@ -8,7 +8,10 @@
 
 , perlPackages
 
-, nix
+, nix-util
+, nix-store
+, nix-main
+, nix-cli
 , nix-perl-bindings
 , git
 
@@ -162,7 +165,7 @@ stdenv.mkDerivation (finalAttrs: {
     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
@@ -199,13 +204,14 @@ stdenv.mkDerivation (finalAttrs: {
     glibcLocales
     libressl.nc
     python3
+    nix-cli
   ];
 
   hydraPath = lib.makeBinPath (
     [
       subversion
       openssh
-      nix
+      nix-cli
       coreutils
       findutils
       pixz
@@ -266,7 +272,7 @@ 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
   '';
@@ -274,5 +280,5 @@ stdenv.mkDerivation (finalAttrs: {
   dontStrip = true;
 
   meta.description = "Build of Hydra on ${stdenv.system}";
-  passthru = { inherit perlDeps nix; };
+  passthru = { inherit perlDeps; };
 })

src/hydra-queue-runner/build-remote.cc

@@ -7,15 +7,12 @@
 
 #include "build-result.hh"
 #include "path.hh"
-#include "legacy-ssh-store.hh"
+#include "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"
@@ -39,108 +36,6 @@ bool ::Machine::isLocalhost() const
 
 namespace nix::build_remote {
 
-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 {
-        auto remoteStore = machine->storeUri.params.find("remote-store");
-        if (remoteStore != machine->storeUri.params.end()) {
-            command.push_back("--store");
-            command.push_back(shellEscape(remoteStore->second));
-        }
-    }
-
-    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());
@@ -203,13 +98,13 @@ static BasicDerivation sendInputs(
         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();
 
@@ -224,11 +119,10 @@ static BuildResult performBuild(
     Store & localStore,
     StorePath drvPath,
     const BasicDerivation & drv,
-    const ServeProto::BuildOptions & options,
     counter & nrStepsBuilding
 )
 {
-    conn.putBuildDerivationRequest(localStore, drvPath, drv, options);
+    auto kont = conn.store->buildDerivationAsync(drvPath, drv, bmNormal);
 
     BuildResult result;
 
@@ -237,7 +131,10 @@ 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 +150,7 @@ 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
@@ -278,55 +175,6 @@ static BuildResult performBuild(
     return result;
 }
 
-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; */
@@ -389,7 +237,6 @@ void RemoteResult::updateWithBuildResult(const nix::BuildResult & buildResult)
 
 void State::buildRemote(ref<Store> destStore,
     ::Machine::ptr machine, Step::ptr step,
-    const ServeProto::BuildOptions & buildOptions,
     RemoteResult & result, std::shared_ptr<ActiveStep> activeStep,
     std::function<void(StepState)> updateStep,
     NarMemberDatas & narMembers)
@@ -404,35 +251,43 @@ void State::buildRemote(ref<Store> destStore,
 
         updateStep(ssConnecting);
 
-        auto storeRef = machine->completeStoreReference();
-
-        auto * pSpecified = std::get_if<StoreReference::Specified>(&storeRef.variant);
-        if (!pSpecified || pSpecified->scheme != "ssh") {
-            throw Error("Currently, only (legacy-)ssh stores are supported!");
-        }
-
-        LegacySSHStoreConfig storeConfig {
-            pSpecified->scheme,
-            pSpecified->authority,
-            storeRef.params
-        };
-
-        auto master = storeConfig.createSSHMaster(
-            false, // no SSH master 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-ng") {
+                    throw Error("Currently, only ssh-ng:// stores are supported!");
+                }
+
+                auto remoteStore = machine->openStore().dynamic_pointer_cast<RemoteStore>();
+                auto remoteStoreConfig = std::dynamic_pointer_cast<SSHStoreConfig>(remoteStore);
+                assert(remoteStore);
+
+                if (machine->isLocalhost()) {
+                    auto rp_new = remoteStoreConfig->remoteProgram.get();
+                    rp_new.push_back("--builders");
+                    rp_new.push_back("");
+                    const_cast<nix::Setting<Strings> &>(remoteStoreConfig->remoteProgram).assign(rp_new);
+                }
+                remoteStoreConfig->extraSshArgs = {
+                    "-a", "-oBatchMode=yes", "-oConnectTimeout=60", "-oTCPKeepAlive=yes"
+                };
+
+                // TODO logging
+                //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;
         }
 
         Finally clearPid([&]() {
             auto activeStepState(activeStep->state_.lock());
-            activeStepState->pid = -1;
 
             /* FIXME: there is a slight race here with step
                cancellation in State::processQueueChange(), which
@@ -442,35 +297,13 @@ 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;
+            // TODO
+            //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->storeUri.render());
-        } catch (EndOfFile & e) {
-            child->sshPid.wait();
-            std::string s = chomp(readFile(result.logFile));
-            throw Error("cannot connect to ‘%1%’: %2%", machine->storeUri.render(), s);
-        }
-
         {
             auto info(machine->state->connectInfo.lock());
             info->consecutiveFailures = 0;
@@ -508,7 +341,6 @@ void State::buildRemote(ref<Store> destStore,
             *localStore,
             step->drvPath,
             resolvedDrv,
-            buildOptions,
             nrStepsBuilding
         );
 
@@ -539,21 +371,12 @@ void State::buildRemote(ref<Store> destStore,
 
             auto now1 = std::chrono::steady_clock::now();
 
-            auto infos = conn.queryPathInfos(*localStore, outputs);
-
-            size_t totalNarSize = 0;
-            for (auto & [_, info] : infos) totalNarSize += info.narSize;
-
-            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->storeUri.render(), 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();
@@ -574,9 +397,11 @@ 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

src/hydra-queue-runner/builder.cc

@@ -98,13 +98,6 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
        it). */
     BuildID buildId;
     std::optional<StorePath> buildDrvPath;
-    // Other fields set below
-    nix::ServeProto::BuildOptions buildOptions {
-        .maxLogSize = maxLogSize,
-        .nrRepeats = step->isDeterministic ? 1u : 0u,
-        .enforceDeterminism = step->isDeterministic,
-        .keepFailed = false,
-    };
 
     auto conn(dbPool.get());
 
@@ -139,18 +132,19 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
             {
                 auto i = jobsetRepeats.find(std::make_pair(build2->projectName, build2->jobsetName));
                 if (i != jobsetRepeats.end())
-                    buildOptions.nrRepeats = std::max(buildOptions.nrRepeats, i->second);
+                    warn("jobset repeats is deprecated; nix stopped supporting this correctly a long time ago.");
             }
         }
         if (!build) build = *dependents.begin();
 
         buildId = build->id;
         buildDrvPath = build->drvPath;
-        buildOptions.maxSilentTime = build->maxSilentTime;
-        buildOptions.buildTimeout = build->buildTimeout;
+        settings.maxLogSize = maxLogSize;
+        settings.maxSilentTime = build->maxSilentTime;
+        settings.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->storeUri.render(), buildId, (dependents.size() - 1));
+            localStore->printStorePath(step->drvPath), 1, machine->storeUri.render(), buildId, (dependents.size() - 1));
     }
 
     if (!buildOneDone)
@@ -178,7 +172,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
                     unlink(result.logFile.c_str());
                 }
             } catch (...) {
-                ignoreException();
+                ignoreExceptionInDestructor();
             }
         }
     });
@@ -211,7 +205,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
 
         try {
             /* FIXME: referring builds may have conflicting timeouts. */
-            buildRemote(destStore, machine, step, buildOptions, result, activeStep, updateStep, narMembers);
+            buildRemote(destStore, machine, step, result, activeStep, updateStep, narMembers);
         } catch (Error & e) {
             if (activeStep->state_.lock()->cancelled) {
                 printInfo("marking step %d of build %d as cancelled", stepNr, buildId);

src/hydra-queue-runner/hydra-queue-runner.cc

@@ -182,7 +182,7 @@ void State::monitorMachinesFile()
         getEnv("NIX_REMOTE_SYSTEMS").value_or(pathExists(defaultMachinesFile) ? defaultMachinesFile : ""), ":");
 
     if (machinesFiles.empty()) {
-        parseMachines("localhost " +
+        parseMachines("ssh-ng://localhost " +
             (settings.thisSystem == "x86_64-linux" ? "x86_64-linux,i686-linux" : settings.thisSystem.get())
             + " - " + std::to_string(settings.maxBuildJobs) + " 1 "
             + concatStringsSep(",", StoreConfig::getDefaultSystemFeatures()));

src/hydra-queue-runner/state.hh

@@ -20,9 +20,7 @@
 #include "store-api.hh"
 #include "sync.hh"
 #include "nar-extractor.hh"
-#include "serve-protocol.hh"
-#include "serve-protocol-impl.hh"
-#include "serve-protocol-connection.hh"
+#include "ssh-store.hh"
 #include "machines.hh"
 
 
@@ -292,14 +290,16 @@ struct Machine : nix::Machine
     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::RemoteStore> store;
     };
 };
 
 
-class HydraConfig;
+struct HydraConfig;
 
 
 class State
@@ -542,7 +542,6 @@ private:
 
     void buildRemote(nix::ref<nix::Store> destStore,
         Machine::ptr machine, Step::ptr step,
-        const nix::ServeProto::BuildOptions & buildOptions,
         RemoteResult & result, std::shared_ptr<ActiveStep> activeStep,
         std::function<void(StepState)> updateStep,
         NarMemberDatas & narMembers);

t/meson.build

@@ -27,6 +27,7 @@ testenv.prepend('PERL5LIB',
   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',