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

@@ -5,6 +5,7 @@
         "flake-compat": [],
         "flake-parts": [],
         "git-hooks-nix": [],
+        "nixfmt": [],
         "nixpkgs": [
           "nixpkgs"
         ],
@@ -12,16 +13,16 @@
         "nixpkgs-regression": []
       },
       "locked": {
-        "lastModified": 1739899400,
-        "narHash": "sha256-q/RgA4bB7zWai4oPySq9mch7qH14IEeom2P64SXdqHs=",
+        "lastModified": 1739571938,
+        "narHash": "sha256-NlaLAed/xei6RWpU2HIIbDjILRC4l1NIfGeyrn7ALQs=",
         "owner": "NixOS",
         "repo": "nix",
-        "rev": "e310c19a1aeb1ce1ed4d41d5ab2d02db596e0918",
+        "rev": "ffc649d2eabdd3e678b5bcc211dd59fd06debf3e",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "2.26-maintenance",
+        "ref": "ssh-ng-extensions-for-hydra",
         "repo": "nix",
         "type": "github"
       }
@@ -29,15 +30,16 @@
     "nix-eval-jobs": {
       "flake": false,
       "locked": {
-        "lastModified": 1739500569,
-        "narHash": "sha256-3wIReAqdTALv39gkWXLMZQvHyBOc3yPkWT2ZsItxedY=",
-        "owner": "nix-community",
+        "lastModified": 1739499741,
+        "narHash": "sha256-dNMJY6+G3PwE8lIAhwetPJdA2DxCEKRXPY/EtHmdDh4=",
+        "owner": "Ericson2314",
         "repo": "nix-eval-jobs",
-        "rev": "4b392b284877d203ae262e16af269f702df036bc",
+        "rev": "de345eb4518d952c2d86261b270f2c31edecd3de",
         "type": "github"
       },
       "original": {
-        "owner": "nix-community",
+        "owner": "Ericson2314",
+        "ref": "nix-2.27",
         "repo": "nix-eval-jobs",
         "type": "github"
       }

flake.nix

@@ -4,7 +4,7 @@
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11-small";
 
   inputs.nix = {
-    url = "github:NixOS/nix/2.26-maintenance";
+    url = "github:NixOS/nix/ssh-ng-extensions-for-hydra";
     inputs.nixpkgs.follows = "nixpkgs";
 
     # hide nix dev tooling from our lock file
@@ -13,10 +13,11 @@
     inputs.nixpkgs-regression.follows = "";
     inputs.nixpkgs-23-11.follows = "";
     inputs.flake-compat.follows = "";
+    inputs.nixfmt.follows = "";
   };
 
   inputs.nix-eval-jobs = {
-    url = "github:nix-community/nix-eval-jobs";
+    url = "github:Ericson2314/nix-eval-jobs/nix-2.27";
     # We want to control the deps precisely
     flake = false;
   };
@@ -85,7 +86,6 @@
             nix-util
             nix-store
             nix-main
-            nix-cmd
             nix-cli
             ;
           nix-perl-bindings = nix.hydraJobs.perlBindings.${system};

foreman/start-manual.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 
-exec mdbook serve \
+mdbook serve \
   --port 63332 \
   --dest-dir ./.hydra-data/manual \
   ./doc/manual/

package.nix

@@ -11,7 +11,6 @@
 , nix-util
 , nix-store
 , nix-main
-, nix-cmd
 , nix-cli
 , nix-perl-bindings
 , git
@@ -179,7 +178,6 @@ stdenv.mkDerivation (finalAttrs: {
     nix-util
     nix-store
     nix-main
-    nix-cmd
     perlDeps
     perl
     boost

src/hydra-build-step/hydra-build-step.cc

@@ -1,213 +0,0 @@
-/* This is a helper program that performs a build step, i.e. a single
-   derivation. In addition to a derivation path, it takes three store
-   URLs as arguments:
-
-   * --store: The store that will hold the resulting store paths
-       (typically a binary cache).
-
-   * --eval-store: The store that holds the .drv files, as produced by
-       hydra-evaluator.
-
-   * --build-store: The store that performs the build (often a
-       SSHStore for remote builds).
-
-   The build log is written to the path indicated by --log-file.
-*/
-
-#include "util.hh"
-#include "shared.hh"
-#include "common-eval-args.hh"
-#include "store-api.hh"
-#include "build-result.hh"
-#include "derivations.hh"
-#include "worker-protocol.hh"
-
-#include <chrono>
-
-using namespace nix;
-
-// FIXME: cut&paste
-static std::string_view getS(const std::vector<Logger::Field> & fields, size_t n)
-{
-    assert(n < fields.size());
-    assert(fields[n].type == Logger::Field::tString);
-    return fields[n].s;
-}
-
-void mainWrapped(std::list<std::string> args)
-{
-    verbosity = lvlError;
-
-    struct MyArgs : MixEvalArgs, MixCommonArgs, RootArgs
-    {
-        Path drvPath;
-        std::optional<std::string> buildStoreUrl;
-        std::optional<Path> logPath;
-        std::optional<uint64_t> maxOutputSize;
-
-        MyArgs() : MixCommonArgs("hydra-build-step")
-        {
-            expectArg("drv-path", &drvPath);
-
-            addFlag({
-                .longName = "build-store",
-                .description = "The Nix store to use for building the derivation.",
-                //.category = category,
-                .labels = {"store-url"},
-                .handler = {&buildStoreUrl},
-            });
-
-            addFlag({
-                .longName = "log-file",
-                .description = "The path to the build log.",
-                .labels = {"path"},
-                .handler = {&logPath},
-            });
-
-            addFlag({
-                .longName = "max-output-size",
-                .description = "Maximum size of the outputs.",
-                .labels = {"bytes"},
-                .handler = {&maxOutputSize},
-            });
-        }
-    };
-
-    /* A logger that intercepts all build log lines and writes them to
-       the log file. */
-    MyArgs myArgs;
-    myArgs.parseCmdline(args);
-
-    struct MyLogger : public Logger
-    {
-        Logger & prev;
-        AutoCloseFD logFile;
-
-        MyLogger(Logger & prev, Path logPath) : prev(prev)
-        {
-            logFile = open(logPath.c_str(), O_CREAT | O_TRUNC | O_WRONLY, 0666);
-            if (!logFile)
-                throw SysError("creating log file '%s'", logPath);
-        }
-
-        void log(Verbosity lvl, std::string_view s) override
-        { prev.log(lvl, s); }
-
-        void logEI(const ErrorInfo & ei) override
-        { prev.logEI(ei); }
-
-        void writeToStdout(std::string_view s) override
-        { prev.writeToStdout(s); }
-
-        void result(ActivityId act, ResultType type, const Fields & fields) override
-        {
-            if (type == resBuildLogLine)
-                writeLine(logFile.get(), std::string(getS(fields, 0)));
-            else
-                prev.result(act, type, fields);
-        }
-    };
-
-    auto destStore = openStore();
-    auto evalStore = myArgs.evalStoreUrl ? openStore(*myArgs.evalStoreUrl) : destStore;
-    auto buildStore = myArgs.buildStoreUrl ? openStore(*myArgs.buildStoreUrl) : destStore;
-
-    auto drvPath = evalStore->parseStorePath(myArgs.drvPath);
-
-    auto drv = evalStore->readDerivation(drvPath);
-    BasicDerivation basicDrv(drv);
-
-    uint64_t overhead = 0;
-
-    /* Gather the inputs. */
-    StorePathSet inputs;
-
-    for (auto & p : drv.inputSrcs)
-        inputs.insert(p);
-
-    for (auto & [drvPath, node] : drv.inputDrvs.map) {
-        auto drv2 = evalStore->readDerivation(drvPath);
-        for (auto & name : node.value) {
-            if (auto i = get(drv2.outputs, name)) {
-                auto outPath = i->path(*evalStore, drv2.name, name);
-                inputs.insert(*outPath);
-                basicDrv.inputSrcs.insert(*outPath);
-            }
-        }
-    }
-
-    /* Ensure that the inputs exist in the destination store (so that
-       the builder can substitute them from the destination
-       store). This is a no-op for regular stores, but for the binary
-       cache store, this will copy the inputs to the binary cache from
-       the local store. */
-    {
-        auto now1 = std::chrono::steady_clock::now();
-
-        debug("sending closure of '%s' to '%s'",
-            evalStore->printStorePath(drvPath), destStore->getUri());
-
-        if (evalStore != destStore)
-            copyClosure(*evalStore, *destStore, drv.inputSrcs, NoRepair, NoCheckSigs);
-
-        copyClosure(*destStore, *buildStore, inputs, NoRepair, NoCheckSigs, Substitute);
-
-        auto now2 = std::chrono::steady_clock::now();
-
-        overhead += std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();
-    }
-
-    /* Perform the build. */
-    if (myArgs.logPath)
-        logger = new MyLogger(*logger, *myArgs.logPath);
-
-    auto buildResult = buildStore->buildDerivation(drvPath, basicDrv);
-
-    /* Copy the output paths from the build store to the destination
-       store. */
-    size_t totalNarSize = 0;
-
-    if (buildResult.success()) {
-
-        std::map<StorePath, ValidPathInfo> infos;
-        StorePathSet outputs;
-        for (auto & [output, realisation] : buildResult.builtOutputs) {
-            auto info = buildStore->queryPathInfo(realisation.outPath);
-            totalNarSize += info->narSize;
-            infos.insert_or_assign(info->path, *info);
-            outputs.insert(info->path);
-        }
-
-        if ((!myArgs.maxOutputSize || totalNarSize <= *myArgs.maxOutputSize)
-            && buildStore != destStore)
-        {
-            debug("copying outputs of '%s' from '%s' (%d bytes)",
-                buildStore->printStorePath(drvPath), buildStore->getUri(), totalNarSize);
-
-            auto now1 = std::chrono::steady_clock::now();
-
-            copyPaths(*buildStore, *destStore, outputs, NoRepair, NoCheckSigs);
-
-            auto now2 = std::chrono::steady_clock::now();
-
-            overhead += std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();
-        }
-    }
-
-    FdSink to { STDOUT_FILENO };
-    WorkerProto::WriteConn wconn {
-        .to = to,
-        // Hardcode latest version because we are deploying hydra
-        // itself atomically
-        .version = PROTOCOL_VERSION,
-    };
-    WorkerProto::write(*evalStore, wconn, buildResult);
-}
-
-int main(int argc, char * * argv)
-{
-    return handleExceptions(argv[0], [&]() {
-        initNix();
-        mainWrapped(argvToStrings(argc, argv));
-    });
-}

src/hydra-build-step/meson.build

@@ -1,14 +0,0 @@
-srcs = files(
-  'hydra-build-step.cc',
-)
-
-hydra_build_step = executable('hydra-build-step',
-  'hydra-build-step.cc',
-  srcs,
-  dependencies: [
-    libhydra_dep,
-    nix_dep,
-    dependency('nix-cmd', required: true)
-  ],
-  install: true,
-)

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

@@ -1,27 +1,178 @@
-#include <math.h>
+#include <algorithm>
+#include <cmath>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 
 #include "build-result.hh"
+#include "path.hh"
+#include "ssh-store.hh"
 #include "serve-protocol.hh"
 #include "state.hh"
 #include "current-process.hh"
 #include "processes.hh"
 #include "util.hh"
+#include "ssh.hh"
 #include "finally.hh"
 #include "url.hh"
-#include "worker-protocol.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 Path createLogFileDir(const std::string & logDir, const StorePath & drvPath)
+static std::pair<Path, AutoCloseFD> openLogFile(const std::string & logDir, const StorePath & drvPath)
 {
     std::string base(drvPath.to_string());
     auto logFile = logDir + "/" + std::string(base, 0, 2) + "/" + std::string(base, 2);
 
     createDirs(dirOf(logFile));
 
-    return logFile;
+    AutoCloseFD logFD = open(logFile.c_str(), O_CREAT | O_TRUNC | O_WRONLY, 0666);
+    if (!logFD) throw SysError("creating log file ‘%s’", logFile);
+
+    return {std::move(logFile), std::move(logFD)};
+}
+
+static BasicDerivation sendInputs(
+    State & state,
+    Step & step,
+    Store & localStore,
+    Store & destStore,
+    ::Machine::Connection & conn,
+    unsigned int & overhead,
+    counter & nrStepsWaiting,
+    counter & nrStepsCopyingTo
+)
+{
+    /* Replace the input derivations by their output paths to send a
+       minimal closure to the builder.
+
+       `tryResolve` currently does *not* rewrite input addresses, so it
+       is safe to do this in all cases. (It should probably have a mode
+       to do that, however, but we would not use it here.)
+     */
+    BasicDerivation basicDrv = ({
+        auto maybeBasicDrv = step.drv->tryResolve(destStore, &localStore);
+        if (!maybeBasicDrv)
+            throw Error(
+                "the derivation '%s' can’t be resolved. It’s probably "
+                "missing some outputs",
+                localStore.printStorePath(step.drvPath));
+        *maybeBasicDrv;
+    });
+
+    /* Ensure that the inputs exist in the destination store. This is
+       a no-op for regular stores, but for the binary cache store,
+       this will copy the inputs to the binary cache from the local
+       store. */
+    if (&localStore != &destStore) {
+        copyClosure(localStore, destStore,
+            step.drv->inputSrcs,
+            NoRepair, NoCheckSigs, NoSubstitute);
+    }
+
+    {
+        auto mc1 = std::make_shared<MaintainCount<counter>>(nrStepsWaiting);
+        mc1.reset();
+        MaintainCount<counter> mc2(nrStepsCopyingTo);
+
+        printMsg(lvlDebug, "sending closure of ‘%s’ to ‘%s’",
+            localStore.printStorePath(step.drvPath), conn.machine->storeUri.render());
+
+        auto now1 = std::chrono::steady_clock::now();
+
+        /* Copy the input closure. */
+        copyClosure(
+            destStore,
+            conn.machine->isLocalhost() ? localStore : *conn.store,
+            basicDrv.inputSrcs,
+            NoRepair,
+            NoCheckSigs,
+            Substitute);
+
+        auto now2 = std::chrono::steady_clock::now();
+
+        overhead += std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();
+    }
+
+    return basicDrv;
+}
+
+static BuildResult performBuild(
+    ::Machine::Connection & conn,
+    Store & localStore,
+    StorePath drvPath,
+    const BasicDerivation & drv,
+    counter & nrStepsBuilding
+)
+{
+    auto kont = conn.store->buildDerivationAsync(drvPath, drv, bmNormal);
+
+    BuildResult result;
+
+    time_t startTime, stopTime;
+
+    startTime = time(0);
+    {
+        MaintainCount<counter> mc(nrStepsBuilding);
+        result = kont();
+        // Without proper call-once functions, we need to manually
+        // delete after calling.
+        kont = {};
+    }
+    stopTime = time(0);
+
+    if (!result.startTime) {
+        // If the builder gave `startTime = 0`, use our measurements
+        // instead of the builder's.
+        //
+        // Note: this represents the duration of a single round, rather
+        // than all rounds.
+        result.startTime = startTime;
+        result.stopTime = stopTime;
+    }
+
+    // If the protocol was too old to give us `builtOutputs`, initialize
+    // it manually by introspecting the derivation.
+    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
+        assert(drv.type().hasKnownOutputPaths());
+        DerivationOutputsAndOptPaths drvOutputs = drv.outputsAndOptPaths(localStore);
+        // Since this a `BasicDerivation`, `staticOutputHashes` will not
+        // do any real work.
+        auto outputHashes = staticOutputHashes(localStore, drv);
+        for (auto & [outputName, output] : drvOutputs) {
+            auto outputPath = output.second;
+            // We’ve just asserted that the output paths of the derivation
+            // were known
+            assert(outputPath);
+            auto outputHash = outputHashes.at(outputName);
+            auto drvOutput = DrvOutput { outputHash, outputName };
+            result.builtOutputs.insert_or_assign(
+                std::move(outputName),
+                Realisation { drvOutput, *outputPath });
+        }
+    }
+
+    return result;
 }
 
 }
@@ -30,14 +181,11 @@ static Path createLogFileDir(const std::string & logDir, const StorePath & drvPa
 
 void RemoteResult::updateWithBuildResult(const nix::BuildResult & buildResult)
 {
-    // FIXME: make RemoteResult inherit BuildResult.
+    startTime = buildResult.startTime;
+    stopTime = buildResult.stopTime;
     timesBuilt = buildResult.timesBuilt;
     errorMsg = buildResult.errorMsg;
     isNonDeterministic = buildResult.isNonDeterministic;
-    if (buildResult.startTime && buildResult.stopTime) {
-        startTime = buildResult.startTime;
-        stopTime = buildResult.stopTime;
-    }
 
     switch ((BuildResult::Status) buildResult.status) {
         case BuildResult::Built:
@@ -89,56 +237,57 @@ 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)
 {
     assert(BuildResult::TimedOut == 8);
 
-    result.logFile = build_remote::createLogFileDir(logDir, step->drvPath);
+    auto [logFile, logFD] = build_remote::openLogFile(logDir, step->drvPath);
+    AutoDelete logFileDel(logFile, false);
+    result.logFile = logFile;
 
     try {
 
-        updateStep(ssBuilding);
-        result.startTime = time(0);
+        updateStep(ssConnecting);
 
-        auto buildStoreUrl = machine->completeStoreReference().render();
+        // FIXME: rewrite to use Store.
+        ::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!");
+                }
 
-        Strings args = {
-            localStore->printStorePath(step->drvPath),
-            "--store", destStore->getUri(),
-            "--eval-store", localStore->getUri(),
-            "--build-store", buildStoreUrl,
-            "--max-silent-time", std::to_string(buildOptions.maxSilentTime),
-            "--timeout", std::to_string(buildOptions.buildTimeout),
-            "--max-build-log-size", std::to_string(buildOptions.maxLogSize),
-            "--max-output-size", std::to_string(maxOutputSize),
-            "--repeat", std::to_string(buildOptions.nrRepeats),
-            "--log-file", result.logFile,
-            // FIXME: step->isDeterministic
+                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};
+            }(),
         };
 
-        // FIXME: set pid for cancellation
-
-        auto [status, childStdout] = [&]() {
-            MaintainCount<counter> mc(nrStepsBuilding);
-            return runProgram({
-                .program = "hydra-build-step",
-                .args = std::move(args),
-            });
-        }();
-
-        #if 0
         {
             auto activeStepState(activeStep->state_.lock());
             if (activeStepState->cancelled) throw Error("step cancelled");
-            activeStepState->pid = conn.store->getConnectionPid();
         }
 
         Finally clearPid([&]() {
             auto activeStepState(activeStep->state_.lock());
-            activeStepState->pid = -1;
 
             /* FIXME: there is a slight race here with step
                cancellation in State::processQueueChange(), which
@@ -147,32 +296,53 @@ void State::buildRemote(ref<Store> destStore,
                possibility that we end up killing another
                process. Meh. */
         });
-        #endif
 
-        result.stopTime = time(0);
+        Finally updateStats([&]() {
+            // TODO
+            //auto stats = conn.store->getConnectionStats();
+            //bytesReceived += stats.bytesReceived;
+            //bytesSent += stats.bytesSent;
+        });
 
-        if (!statusOk(status))
-            throw ExecError(status, fmt("hydra-build-step %s with output:\n%s", statusToString(status), stdout));
-
-        /* The build was executed successfully, so clear the failure
-           count for this machine. */
         {
             auto info(machine->state->connectInfo.lock());
             info->consecutiveFailures = 0;
         }
 
-        StringSource from { childStdout };
-        /* Read the BuildResult from the child. */
-        WorkerProto::ReadConn rconn {
-            .from = from,
-            // Hardcode latest version because we are deploying hydra
-            // itself atomically
-            .version = PROTOCOL_VERSION,
-        };
-        result.overhead += readNum<uint64_t>(rconn.from);
-        auto totalNarSize = readNum<uint64_t>(rconn.from);
-        auto buildResult = WorkerProto::Serialise<BuildResult>::read(*localStore, rconn);
+        /* Gather the inputs. If the remote side is Nix <= 1.9, we have to
+           copy the entire closure of ‘drvPath’, as well as the required
+           outputs of the input derivations. On Nix > 1.9, we only need to
+           copy the immediate sources of the derivation and the required
+           outputs of the input derivations. */
+        updateStep(ssSendingInputs);
+        BasicDerivation resolvedDrv = build_remote::sendInputs(*this, *step, *localStore, *destStore, conn, result.overhead, nrStepsWaiting, nrStepsCopyingTo);
 
+        logFileDel.cancel();
+
+        /* Truncate the log to get rid of messages about substitutions
+            etc. on the remote system. */
+        if (lseek(logFD.get(), SEEK_SET, 0) != 0)
+            throw SysError("seeking to the start of log file ‘%s’", result.logFile);
+
+        if (ftruncate(logFD.get(), 0) == -1)
+            throw SysError("truncating log file ‘%s’", result.logFile);
+
+        logFD = -1;
+
+        /* Do the build. */
+        printMsg(lvlDebug, "building ‘%s’ on ‘%s’",
+            localStore->printStorePath(step->drvPath),
+            machine->storeUri.render());
+
+        updateStep(ssBuilding);
+
+        BuildResult buildResult = build_remote::performBuild(
+            conn,
+            *localStore,
+            step->drvPath,
+            resolvedDrv,
+            nrStepsBuilding
+        );
 
         result.updateWithBuildResult(buildResult);
 
@@ -180,13 +350,6 @@ void State::buildRemote(ref<Store> destStore,
 
         result.errorMsg = "";
 
-        /* If the NAR size limit was exceeded, then hydra-build-step
-           will not have copied the output paths. */
-        if (totalNarSize > maxOutputSize) {
-            result.stepStatus = bsNarSizeLimitExceeded;
-            return;
-        }
-
         /* If the path was substituted or already valid, then we didn't
            get a build log. */
         if (result.isCached) {
@@ -196,6 +359,50 @@ void State::buildRemote(ref<Store> destStore,
             result.logFile = "";
         }
 
+        StorePathSet outputs;
+        for (auto & [_, realisation] : buildResult.builtOutputs)
+            outputs.insert(realisation.outPath);
+
+        /* Copy the output paths. */
+        if (!machine->isLocalhost() || localStore != std::shared_ptr<Store>(destStore)) {
+            updateStep(ssReceivingOutputs);
+
+            MaintainCount<counter> mc(nrStepsCopyingFrom);
+
+            auto now1 = std::chrono::steady_clock::now();
+
+            /* Copy each path. */
+            printMsg(lvlDebug, "copying outputs of ‘%s’ from ‘%s’",
+                localStore->printStorePath(step->drvPath), machine->storeUri.render());
+
+            copyClosure(*conn.store, *destStore, outputs);
+
+            auto now2 = std::chrono::steady_clock::now();
+
+            result.overhead += std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();
+        }
+
+        /* Register the outputs of the newly built drv */
+        if (experimentalFeatureSettings.isEnabled(Xp::CaDerivations)) {
+            auto outputHashes = staticOutputHashes(*localStore, *step->drv);
+            for (auto & [outputName, realisation] : buildResult.builtOutputs) {
+                // Register the resolved drv output
+                destStore->registerDrvOutput(realisation);
+
+                // Also register the unresolved one
+                auto unresolvedRealisation = realisation;
+                unresolvedRealisation.signatures.clear();
+                unresolvedRealisation.id.drvHash = outputHashes.at(outputName);
+                destStore->registerDrvOutput(unresolvedRealisation);
+            }
+        }
+
+        /* 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
            passed. This period increases on every consecutive

src/hydra-queue-runner/builder.cc

@@ -3,7 +3,6 @@
 #include "state.hh"
 #include "hydra-build-result.hh"
 #include "finally.hh"
-#include "terminal.hh"
 #include "binary-cache-store.hh"
 
 using namespace nix;
@@ -99,13 +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());
 
@@ -140,18 +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)
@@ -212,7 +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);
@@ -220,7 +213,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
                 result.canRetry = false;
             } else {
                 result.stepStatus = bsAborted;
-                result.errorMsg = filterANSIEscapes(e.msg(), true);
+                result.errorMsg = e.msg();
                 result.canRetry = true;
             }
         }

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()));
@@ -550,11 +550,12 @@ void State::dumpStatus(Connection & conn)
         {"nrQueuedBuilds", builds.lock()->size()},
         {"nrActiveSteps", activeSteps_.lock()->size()},
         {"nrStepsBuilding", nrStepsBuilding.load()},
-        #if 0
         {"nrStepsCopyingTo", nrStepsCopyingTo.load()},
         {"nrStepsCopyingFrom", nrStepsCopyingFrom.load()},
-        #endif
+        {"nrStepsWaiting", nrStepsWaiting.load()},
         {"nrUnsupportedSteps", nrUnsupportedSteps.load()},
+        {"bytesSent", bytesSent.load()},
+        {"bytesReceived", bytesReceived.load()},
         {"nrBuildsRead", nrBuildsRead.load()},
         {"buildReadTimeMs", buildReadTimeMs.load()},
         {"buildReadTimeAvgMs", nrBuildsRead == 0 ? 0.0 : (float) buildReadTimeMs / nrBuildsRead},

src/hydra-queue-runner/state.hh

@@ -20,7 +20,7 @@
 #include "store-api.hh"
 #include "sync.hh"
 #include "nar-extractor.hh"
-#include "serve-protocol.hh"
+#include "ssh-store.hh"
 #include "machines.hh"
 
 
@@ -288,10 +288,18 @@ struct Machine : nix::Machine
     }
 
     bool isLocalhost() const;
+
+    // A connection to a machine
+    struct Connection {
+        // Backpointer to the machine
+        ptr machine;
+        // Opened store
+        nix::ref<nix::RemoteStore> store;
+    };
 };
 
 
-class HydraConfig;
+struct HydraConfig;
 
 
 class State
@@ -352,10 +360,9 @@ private:
     counter nrStepsStarted{0};
     counter nrStepsDone{0};
     counter nrStepsBuilding{0};
-    #if 0
     counter nrStepsCopyingTo{0};
     counter nrStepsCopyingFrom{0};
-    #endif
+    counter nrStepsWaiting{0};
     counter nrUnsupportedSteps{0};
     counter nrRetries{0};
     counter maxNrRetries{0};
@@ -364,6 +371,8 @@ private:
     counter nrQueueWakeups{0};
     counter nrDispatcherWakeups{0};
     counter dispatchTimeMs{0};
+    counter bytesSent{0};
+    counter bytesReceived{0};
     counter nrActiveDbUpdates{0};
 
     /* Specific build to do for --build-one (testing only). */
@@ -533,7 +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);

src/meson.build

@@ -1,6 +1,5 @@
 # Native code
 subdir('libhydra')
-subdir('hydra-build-step')
 subdir('hydra-evaluator')
 subdir('hydra-queue-runner')
 

t/meson.build

@@ -28,7 +28,6 @@ testenv.prepend('PERL5LIB',
 )
 testenv.prepend('PATH',
   fs.parent(find_program('nix').full_path()),
-  fs.parent(hydra_build_step.full_path()),
   fs.parent(hydra_evaluator.full_path()),
   fs.parent(hydra_queue_runner.full_path()),
   meson.project_source_root() / 'src/script',