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).

flake.lock

@@ -1,51 +1,10 @@
 {
   "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"
-        ],
         "nixpkgs": [
           "nixpkgs"
         ],
@@ -53,88 +12,58 @@
         "nixpkgs-regression": []
       },
       "locked": {
-        "lastModified": 1726787955,
+        "lastModified": 1739899400,
-        "narHash": "sha256-XFznzb8L4SdUm9u+w3DPpMWJhffuv+/6+aiVl00slns=",
+        "narHash": "sha256-q/RgA4bB7zWai4oPySq9mch7qH14IEeom2P64SXdqHs=",
         "owner": "NixOS",
         "repo": "nix",
-        "rev": "a7fdef6858dd45b9d7bda7c92324c63faee7f509",
+        "rev": "e310c19a1aeb1ce1ed4d41d5ab2d02db596e0918",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "2.24-maintenance",
+        "ref": "2.26-maintenance",
         "repo": "nix",
         "type": "github"
       }
     },
     "nix-eval-jobs": {
-      "inputs": {
+      "flake": false,
-        "flake-parts": "flake-parts",
-        "nix-github-actions": [],
-        "nixpkgs": [
-          "nixpkgs"
-        ],
-        "treefmt-nix": "treefmt-nix"
-      },
       "locked": {
-        "lastModified": 1733814344,
+        "lastModified": 1739500569,
-        "narHash": "sha256-3wwtKpS5tUBdjaGeSia7CotonbiRB6K5Kp0dsUt3nzU=",
+        "narHash": "sha256-3wIReAqdTALv39gkWXLMZQvHyBOc3yPkWT2ZsItxedY=",
         "owner": "nix-community",
         "repo": "nix-eval-jobs",
-        "rev": "889ea1406736b53cf165b6c28398aae3969418d1",
+        "rev": "4b392b284877d203ae262e16af269f702df036bc",
         "type": "github"
       },
       "original": {
         "owner": "nix-community",
-        "ref": "release-2.24",
         "repo": "nix-eval-jobs",
         "type": "github"
       }
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1726688310,
+        "lastModified": 1739461644,
-        "narHash": "sha256-Xc9lEtentPCEtxc/F1e6jIZsd4MPDYv4Kugl9WtXlz0=",
+        "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 +1,25 @@
 {
   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 = {
-  inputs.nix.url = "github:NixOS/nix/2.24-maintenance";
+    url = "github:NixOS/nix/2.26-maintenance";
-  inputs.nix.inputs.nixpkgs.follows = "nixpkgs";
+    inputs.nixpkgs.follows = "nixpkgs";
-  inputs.nix.inputs.libgit2.follows = "libgit2";
 
-  inputs.nix-eval-jobs.url = "github:nix-community/nix-eval-jobs/release-2.24";
+    # hide nix dev tooling from our lock file
-  inputs.nix-eval-jobs.inputs.nixpkgs.follows = "nixpkgs";
+    inputs.flake-parts.follows = "";
+    inputs.git-hooks-nix.follows = "";
+    inputs.nixpkgs-regression.follows = "";
+    inputs.nixpkgs-23-11.follows = "";
+    inputs.flake-compat.follows = "";
+  };
 
-  # hide nix dev tooling from our lock file
+  inputs.nix-eval-jobs = {
-  inputs.nix.inputs.flake-parts.follows = "";
+    url = "github:nix-community/nix-eval-jobs";
-  inputs.nix.inputs.git-hooks-nix.follows = "";
+    # We want to control the deps precisely
-  inputs.nix.inputs.nixpkgs-regression.follows = "";
+    flake = false;
-  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 = "";
 
   outputs = { self, nixpkgs, nix, nix-eval-jobs, ... }:
     let
@@ -30,9 +30,9 @@
 
       # 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 +74,19 @@
       });
 
       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

@@ -7,140 +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()) {
+        copyClosure(
-            StorePathSet closure;
+            destStore,
-            destStore.computeFSClosure(basicDrv.inputSrcs, closure);
+            conn.machine->isLocalhost() ? localStore : *conn.store,
-            copyPaths(destStore, localStore, closure, NoRepair, NoCheckSigs, NoSubstitute);
+            basicDrv.inputSrcs,
-        } else {
+            NoRepair,
-            copyClosureTo(conn, destStore, basicDrv.inputSrcs, Substitute);
+            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;
+            auto stats = conn.store->getConnectionStats();
-            bytesSent += conn.to.written;
+            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)",
+            printMsg(lvlDebug, "copying outputs of ‘%s’ from ‘%s’",
-                localStore->printStorePath(step->drvPath), machine->sshName, totalNarSize);
+                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. */
+        /* Shut down the connection done by RAII.
-        child->in = -1;
+
-        child->sshPid.wait();
+           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;

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);
             }
 

src/hydra-queue-runner/dispatcher.cc

@@ -256,7 +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;
                 }
 

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")) {
+    for (auto && machine_ : nix::Machine::parseConfig({}, contents)) {
-        line = trim(std::string(line, 0, line.find('#')));
+        auto machine = std::make_shared<::Machine>(std::move(machine_));
-        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] != "-"
-                ? tokens[7]
-                : "",
-        });
-
-        machine->sshName = tokens[0];
 
         /* 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;
             }
         }
 

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>
@@ -21,9 +20,7 @@
 #include "store-api.hh"
 #include "sync.hh"
 #include "nar-extractor.hh"
-#include "serve-protocol.hh"
+#include "legacy-ssh-store.hh"
-#include "serve-protocol-impl.hh"
-#include "serve-protocol-connection.hh"
 #include "machines.hh"
 
 
@@ -241,10 +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};
@@ -294,16 +287,14 @@ struct Machine : nix::Machine
         return true;
     }
 
-    bool isLocalhost()
+    bool isLocalhost() const;
-    {
-        std::regex r("^(ssh://|ssh-ng://)?localhost$");
-        return std::regex_search(sshName, r);
-    }
 
     // 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;
     };
 };
 
@@ -358,7 +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. */

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',