Merge pull request #4592 from NixOS/ca/remote-cache

Substitute content-addressed derivations

src/libstore/build/derivation-goal.cc

@@ -170,7 +170,7 @@ void DerivationGoal::getDerivation()
         return;
     }
 
-    addWaitee(upcast_goal(worker.makeSubstitutionGoal(drvPath)));
+    addWaitee(upcast_goal(worker.makePathSubstitutionGoal(drvPath)));
 
     state = &DerivationGoal::loadDerivation;
 }
@@ -246,14 +246,19 @@ void DerivationGoal::haveDerivation()
        through substitutes.  If that doesn't work, we'll build
        them. */
     if (settings.useSubstitutes && parsedDrv->substitutesAllowed())
-        for (auto & [_, status] : initialOutputs) {
+        for (auto & [outputName, status] : initialOutputs) {
             if (!status.wanted) continue;
-            if (!status.known) {
-                warn("do not know how to query for unknown floating content-addressed derivation output yet");
-                /* Nothing to wait for; tail call */
-                return DerivationGoal::gaveUpOnSubstitution();
-            }
-            addWaitee(upcast_goal(worker.makeSubstitutionGoal(
+            if (!status.known)
+                addWaitee(
+                    upcast_goal(
+                        worker.makeDrvOutputSubstitutionGoal(
+                            DrvOutput{status.outputHash, outputName},
+                            buildMode == bmRepair ? Repair : NoRepair
+                        )
+                    )
+                );
+            else
+                addWaitee(upcast_goal(worker.makePathSubstitutionGoal(
                     status.known->path,
                     buildMode == bmRepair ? Repair : NoRepair,
                     getDerivationCA(*drv))));
@@ -337,7 +342,7 @@ void DerivationGoal::gaveUpOnSubstitution()
         if (!settings.useSubstitutes)
             throw Error("dependency '%s' of '%s' does not exist, and substitution is disabled",
                 worker.store.printStorePath(i), worker.store.printStorePath(drvPath));
-        addWaitee(upcast_goal(worker.makeSubstitutionGoal(i)));
+        addWaitee(upcast_goal(worker.makePathSubstitutionGoal(i)));
     }
 
     if (waitees.empty()) /* to prevent hang (no wake-up event) */
@@ -388,7 +393,7 @@ void DerivationGoal::repairClosure()
             worker.store.printStorePath(i), worker.store.printStorePath(drvPath));
         auto drvPath2 = outputsToDrv.find(i);
         if (drvPath2 == outputsToDrv.end())
-            addWaitee(upcast_goal(worker.makeSubstitutionGoal(i, Repair)));
+            addWaitee(upcast_goal(worker.makePathSubstitutionGoal(i, Repair)));
         else
             addWaitee(worker.makeDerivationGoal(drvPath2->second, StringSet(), bmRepair));
     }

src/libstore/build/drv-output-substitution-goal.cc

@@ -0,0 +1,95 @@
+#include "drv-output-substitution-goal.hh"
+#include "worker.hh"
+#include "substitution-goal.hh"
+
+namespace nix {
+
+DrvOutputSubstitutionGoal::DrvOutputSubstitutionGoal(const DrvOutput& id, Worker & worker, RepairFlag repair, std::optional<ContentAddress> ca)
+    : Goal(worker)
+    , id(id)
+{
+    state = &DrvOutputSubstitutionGoal::init;
+    name = fmt("substitution of '%s'", id.to_string());
+    trace("created");
+}
+
+
+void DrvOutputSubstitutionGoal::init()
+{
+    trace("init");
+    subs = settings.useSubstitutes ? getDefaultSubstituters() : std::list<ref<Store>>();
+    tryNext();
+}
+
+void DrvOutputSubstitutionGoal::tryNext()
+{
+    trace("Trying next substituter");
+
+    if (subs.size() == 0) {
+        /* None left.  Terminate this goal and let someone else deal
+           with it. */
+        debug("drv output '%s' is required, but there is no substituter that can provide it", id.to_string());
+
+        /* Hack: don't indicate failure if there were no substituters.
+           In that case the calling derivation should just do a
+           build. */
+        amDone(substituterFailed ? ecFailed : ecNoSubstituters);
+
+        if (substituterFailed) {
+            worker.failedSubstitutions++;
+            worker.updateProgress();
+        }
+
+        return;
+    }
+
+    auto sub = subs.front();
+    subs.pop_front();
+
+    // FIXME: Make async
+    outputInfo = sub->queryRealisation(id);
+    if (!outputInfo) {
+        tryNext();
+        return;
+    }
+
+    addWaitee(worker.makePathSubstitutionGoal(outputInfo->outPath));
+
+    if (waitees.empty()) outPathValid();
+    else state = &DrvOutputSubstitutionGoal::outPathValid;
+}
+
+void DrvOutputSubstitutionGoal::outPathValid()
+{
+    assert(outputInfo);
+    trace("Output path substituted");
+
+    if (nrFailed > 0) {
+        debug("The output path of the derivation output '%s' could not be substituted", id.to_string());
+        amDone(nrNoSubstituters > 0 || nrIncompleteClosure > 0 ? ecIncompleteClosure : ecFailed);
+        return;
+    }
+
+    worker.store.registerDrvOutput(*outputInfo);
+    finished();
+}
+
+void DrvOutputSubstitutionGoal::finished()
+{
+    trace("finished");
+    amDone(ecSuccess);
+}
+
+string DrvOutputSubstitutionGoal::key()
+{
+    /* "a$" ensures substitution goals happen before derivation
+       goals. */
+    return "a$" + std::string(id.to_string());
+}
+
+void DrvOutputSubstitutionGoal::work()
+{
+    (this->*state)();
+}
+
+}

src/libstore/build/drv-output-substitution-goal.hh

@@ -0,0 +1,50 @@
+#pragma once
+
+#include "store-api.hh"
+#include "goal.hh"
+#include "realisation.hh"
+
+namespace nix {
+
+class Worker;
+
+// Substitution of a derivation output.
+// This is done in three steps:
+// 1. Fetch the output info from a substituter
+// 2. Substitute the corresponding output path
+// 3. Register the output info
+class DrvOutputSubstitutionGoal : public Goal {
+private:
+    // The drv output we're trying to substitue
+    DrvOutput id;
+
+    // The realisation corresponding to the given output id.
+    // Will be filled once we can get it.
+    std::optional<Realisation> outputInfo;
+
+    /* The remaining substituters. */
+    std::list<ref<Store>> subs;
+
+    /* Whether a substituter failed. */
+    bool substituterFailed = false;
+
+public:
+    DrvOutputSubstitutionGoal(const DrvOutput& id, Worker & worker, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
+
+    typedef void (DrvOutputSubstitutionGoal::*GoalState)();
+    GoalState state;
+
+    void init();
+    void tryNext();
+    void outPathValid();
+    void finished();
+
+    void timedOut(Error && ex) override { abort(); };
+
+    string key() override;
+
+    void work() override;
+
+};
+
+}

src/libstore/build/entry-points.cc

@@ -15,7 +15,7 @@ void Store::buildPaths(const std::vector<StorePathWithOutputs> & drvPaths, Build
         if (path.path.isDerivation())
             goals.insert(worker.makeDerivationGoal(path.path, path.outputs, buildMode));
         else
-            goals.insert(worker.makeSubstitutionGoal(path.path, buildMode == bmRepair ? Repair : NoRepair));
+            goals.insert(worker.makePathSubstitutionGoal(path.path, buildMode == bmRepair ? Repair : NoRepair));
     }
 
     worker.run(goals);
@@ -31,7 +31,7 @@ void Store::buildPaths(const std::vector<StorePathWithOutputs> & drvPaths, Build
         }
         if (i->exitCode != Goal::ecSuccess) {
             if (auto i2 = dynamic_cast<DerivationGoal *>(i.get())) failed.insert(i2->drvPath);
-            else if (auto i2 = dynamic_cast<SubstitutionGoal *>(i.get())) failed.insert(i2->storePath);
+            else if (auto i2 = dynamic_cast<PathSubstitutionGoal *>(i.get())) failed.insert(i2->storePath);
         }
     }
 
@@ -90,7 +90,7 @@ void Store::ensurePath(const StorePath & path)
     if (isValidPath(path)) return;
 
     Worker worker(*this);
-    GoalPtr goal = worker.makeSubstitutionGoal(path);
+    GoalPtr goal = worker.makePathSubstitutionGoal(path);
     Goals goals = {goal};
 
     worker.run(goals);
@@ -108,7 +108,7 @@ void Store::ensurePath(const StorePath & path)
 void LocalStore::repairPath(const StorePath & path)
 {
     Worker worker(*this);
-    GoalPtr goal = worker.makeSubstitutionGoal(path, Repair);
+    GoalPtr goal = worker.makePathSubstitutionGoal(path, Repair);
     Goals goals = {goal};
 
     worker.run(goals);

src/libstore/build/substitution-goal.cc

@@ -5,20 +5,20 @@
 
 namespace nix {
 
-SubstitutionGoal::SubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair, std::optional<ContentAddress> ca)
+PathSubstitutionGoal::PathSubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair, std::optional<ContentAddress> ca)
     : Goal(worker)
     , storePath(storePath)
     , repair(repair)
     , ca(ca)
 {
-    state = &SubstitutionGoal::init;
+    state = &PathSubstitutionGoal::init;
     name = fmt("substitution of '%s'", worker.store.printStorePath(this->storePath));
     trace("created");
     maintainExpectedSubstitutions = std::make_unique<MaintainCount<uint64_t>>(worker.expectedSubstitutions);
 }
 
 
-SubstitutionGoal::~SubstitutionGoal()
+PathSubstitutionGoal::~PathSubstitutionGoal()
 {
     try {
         if (thr.joinable()) {
@@ -32,13 +32,13 @@ SubstitutionGoal::~SubstitutionGoal()
 }
 
 
-void SubstitutionGoal::work()
+void PathSubstitutionGoal::work()
 {
     (this->*state)();
 }
 
 
-void SubstitutionGoal::init()
+void PathSubstitutionGoal::init()
 {
     trace("init");
 
@@ -59,7 +59,7 @@ void SubstitutionGoal::init()
 }
 
 
-void SubstitutionGoal::tryNext()
+void PathSubstitutionGoal::tryNext()
 {
     trace("trying next substituter");
 
@@ -154,16 +154,16 @@ void SubstitutionGoal::tryNext()
        paths referenced by this one. */
     for (auto & i : info->references)
         if (i != storePath) /* ignore self-references */
-            addWaitee(worker.makeSubstitutionGoal(i));
+            addWaitee(worker.makePathSubstitutionGoal(i));
 
     if (waitees.empty()) /* to prevent hang (no wake-up event) */
         referencesValid();
     else
-        state = &SubstitutionGoal::referencesValid;
+        state = &PathSubstitutionGoal::referencesValid;
 }
 
 
-void SubstitutionGoal::referencesValid()
+void PathSubstitutionGoal::referencesValid()
 {
     trace("all references realised");
 
@@ -177,12 +177,12 @@ void SubstitutionGoal::referencesValid()
         if (i != storePath) /* ignore self-references */
             assert(worker.store.isValidPath(i));
 
-    state = &SubstitutionGoal::tryToRun;
+    state = &PathSubstitutionGoal::tryToRun;
     worker.wakeUp(shared_from_this());
 }
 
 
-void SubstitutionGoal::tryToRun()
+void PathSubstitutionGoal::tryToRun()
 {
     trace("trying to run");
 
@@ -221,11 +221,11 @@ void SubstitutionGoal::tryToRun()
 
     worker.childStarted(shared_from_this(), {outPipe.readSide.get()}, true, false);
 
-    state = &SubstitutionGoal::finished;
+    state = &PathSubstitutionGoal::finished;
 }
 
 
-void SubstitutionGoal::finished()
+void PathSubstitutionGoal::finished()
 {
     trace("substitute finished");
 
@@ -249,7 +249,7 @@ void SubstitutionGoal::finished()
         }
 
         /* Try the next substitute. */
-        state = &SubstitutionGoal::tryNext;
+        state = &PathSubstitutionGoal::tryNext;
         worker.wakeUp(shared_from_this());
         return;
     }
@@ -278,12 +278,12 @@ void SubstitutionGoal::finished()
 }
 
 
-void SubstitutionGoal::handleChildOutput(int fd, const string & data)
+void PathSubstitutionGoal::handleChildOutput(int fd, const string & data)
 {
 }
 
 
-void SubstitutionGoal::handleEOF(int fd)
+void PathSubstitutionGoal::handleEOF(int fd)
 {
     if (fd == outPipe.readSide.get()) worker.wakeUp(shared_from_this());
 }

src/libstore/build/substitution-goal.hh

@@ -8,7 +8,7 @@ namespace nix {
 
 class Worker;
 
-struct SubstitutionGoal : public Goal
+struct PathSubstitutionGoal : public Goal
 {
     /* The store path that should be realised through a substitute. */
     StorePath storePath;
@@ -47,14 +47,15 @@ struct SubstitutionGoal : public Goal
     std::unique_ptr<MaintainCount<uint64_t>> maintainExpectedSubstitutions,
         maintainRunningSubstitutions, maintainExpectedNar, maintainExpectedDownload;
 
-    typedef void (SubstitutionGoal::*GoalState)();
+    typedef void (PathSubstitutionGoal::*GoalState)();
     GoalState state;
 
     /* Content address for recomputing store path */
     std::optional<ContentAddress> ca;
 
-    SubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
-    ~SubstitutionGoal();
+public:
+    PathSubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
+    ~PathSubstitutionGoal();
 
     void timedOut(Error && ex) override { abort(); };
 

src/libstore/build/worker.cc

@@ -1,6 +1,7 @@
 #include "machines.hh"
 #include "worker.hh"
 #include "substitution-goal.hh"
+#include "drv-output-substitution-goal.hh"
 #include "local-derivation-goal.hh"
 #include "hook-instance.hh"
 
@@ -78,20 +79,32 @@ std::shared_ptr<DerivationGoal> Worker::makeBasicDerivationGoal(const StorePath
 }
 
 
-std::shared_ptr<SubstitutionGoal> Worker::makeSubstitutionGoal(const StorePath & path, RepairFlag repair, std::optional<ContentAddress> ca)
+std::shared_ptr<PathSubstitutionGoal> Worker::makePathSubstitutionGoal(const StorePath & path, RepairFlag repair, std::optional<ContentAddress> ca)
 {
-    std::weak_ptr<SubstitutionGoal> & goal_weak = substitutionGoals[path];
+    std::weak_ptr<PathSubstitutionGoal> & goal_weak = substitutionGoals[path];
     auto goal = goal_weak.lock(); // FIXME
     if (!goal) {
-        goal = std::make_shared<SubstitutionGoal>(path, *this, repair, ca);
+        goal = std::make_shared<PathSubstitutionGoal>(path, *this, repair, ca);
         goal_weak = goal;
         wakeUp(goal);
     }
     return goal;
 }
 
-template<typename G>
-static void removeGoal(std::shared_ptr<G> goal, std::map<StorePath, std::weak_ptr<G>> & goalMap)
+std::shared_ptr<DrvOutputSubstitutionGoal> Worker::makeDrvOutputSubstitutionGoal(const DrvOutput& id, RepairFlag repair, std::optional<ContentAddress> ca)
+{
+    std::weak_ptr<DrvOutputSubstitutionGoal> & goal_weak = drvOutputSubstitutionGoals[id];
+    auto goal = goal_weak.lock(); // FIXME
+    if (!goal) {
+        goal = std::make_shared<DrvOutputSubstitutionGoal>(id, *this, repair, ca);
+        goal_weak = goal;
+        wakeUp(goal);
+    }
+    return goal;
+}
+
+template<typename K, typename G>
+static void removeGoal(std::shared_ptr<G> goal, std::map<K, std::weak_ptr<G>> & goalMap)
 {
     /* !!! inefficient */
     for (auto i = goalMap.begin();
@@ -109,8 +122,10 @@ void Worker::removeGoal(GoalPtr goal)
 {
     if (auto drvGoal = std::dynamic_pointer_cast<DerivationGoal>(goal))
         nix::removeGoal(drvGoal, derivationGoals);
-    else if (auto subGoal = std::dynamic_pointer_cast<SubstitutionGoal>(goal))
+    else if (auto subGoal = std::dynamic_pointer_cast<PathSubstitutionGoal>(goal))
         nix::removeGoal(subGoal, substitutionGoals);
+    else if (auto subGoal = std::dynamic_pointer_cast<DrvOutputSubstitutionGoal>(goal))
+        nix::removeGoal(subGoal, drvOutputSubstitutionGoals);
     else
         assert(false);
     if (topGoals.find(goal) != topGoals.end()) {
@@ -217,7 +232,7 @@ void Worker::run(const Goals & _topGoals)
         topGoals.insert(i);
         if (auto goal = dynamic_cast<DerivationGoal *>(i.get())) {
             topPaths.push_back({goal->drvPath, goal->wantedOutputs});
-        } else if (auto goal = dynamic_cast<SubstitutionGoal *>(i.get())) {
+        } else if (auto goal = dynamic_cast<PathSubstitutionGoal *>(i.get())) {
             topPaths.push_back({goal->storePath});
         }
     }
@@ -471,7 +486,10 @@ void Worker::markContentsGood(const StorePath & path)
 }
 
 
-GoalPtr upcast_goal(std::shared_ptr<SubstitutionGoal> subGoal) {
+GoalPtr upcast_goal(std::shared_ptr<PathSubstitutionGoal> subGoal) {
+    return subGoal;
+}
+GoalPtr upcast_goal(std::shared_ptr<DrvOutputSubstitutionGoal> subGoal) {
     return subGoal;
 }
 

src/libstore/build/worker.hh

@@ -4,6 +4,7 @@
 #include "lock.hh"
 #include "store-api.hh"
 #include "goal.hh"
+#include "realisation.hh"
 
 #include <future>
 #include <thread>
@@ -12,18 +13,20 @@ namespace nix {
 
 /* Forward definition. */
 struct DerivationGoal;
-struct SubstitutionGoal;
+struct PathSubstitutionGoal;
+class DrvOutputSubstitutionGoal;
 
 /* Workaround for not being able to declare a something like
 
-     class SubstitutionGoal : public Goal;
+     class PathSubstitutionGoal : public Goal;
 
    even when Goal is a complete type.
 
    This is still a static cast. The purpose of exporting it is to define it in
-   a place where `SubstitutionGoal` is concrete, and use it in a place where it
+   a place where `PathSubstitutionGoal` is concrete, and use it in a place where it
    is opaque. */
-GoalPtr upcast_goal(std::shared_ptr<SubstitutionGoal> subGoal);
+GoalPtr upcast_goal(std::shared_ptr<PathSubstitutionGoal> subGoal);
+GoalPtr upcast_goal(std::shared_ptr<DrvOutputSubstitutionGoal> subGoal);
 
 typedef std::chrono::time_point<std::chrono::steady_clock> steady_time_point;
 
@@ -72,7 +75,8 @@ private:
     /* Maps used to prevent multiple instantiations of a goal for the
        same derivation / path. */
     std::map<StorePath, std::weak_ptr<DerivationGoal>> derivationGoals;
-    std::map<StorePath, std::weak_ptr<SubstitutionGoal>> substitutionGoals;
+    std::map<StorePath, std::weak_ptr<PathSubstitutionGoal>> substitutionGoals;
+    std::map<DrvOutput, std::weak_ptr<DrvOutputSubstitutionGoal>> drvOutputSubstitutionGoals;
 
     /* Goals waiting for busy paths to be unlocked. */
     WeakGoals waitingForAnyGoal;
@@ -146,7 +150,8 @@ public:
         const StringSet & wantedOutputs, BuildMode buildMode = bmNormal);
 
     /* substitution goal */
-    std::shared_ptr<SubstitutionGoal> makeSubstitutionGoal(const StorePath & storePath, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
+    std::shared_ptr<PathSubstitutionGoal> makePathSubstitutionGoal(const StorePath & storePath, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
+    std::shared_ptr<DrvOutputSubstitutionGoal> makeDrvOutputSubstitutionGoal(const DrvOutput & id, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
 
     /* Remove a dead goal. */
     void removeGoal(GoalPtr goal);

src/libstore/local-store.hh

@@ -281,7 +281,9 @@ private:
     void createUser(const std::string & userName, uid_t userId) override;
 
     friend struct LocalDerivationGoal;
+    friend struct PathSubstitutionGoal;
     friend struct SubstitutionGoal;
+    friend struct DerivationGoal;
 };
 
 

tests/ca/substitute.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+# Ensure that binary substitution works properly with ca derivations
+
+source common.sh
+
+sed -i 's/experimental-features .*/& ca-derivations ca-references/' "$NIX_CONF_DIR"/nix.conf
+
+export REMOTE_STORE=file://$TEST_ROOT/binary_cache
+
+buildDrvs () {
+    nix build --file ./content-addressed.nix -L --no-link "$@"
+}
+
+# Populate the remote cache
+buildDrvs --post-build-hook ../push-to-store.sh
+
+# Restart the build on an empty store, ensuring that we don't build
+clearStore
+buildDrvs --substitute --substituters $REMOTE_STORE --no-require-sigs -j0
+

tests/local.mk

@@ -41,7 +41,8 @@ nix_tests = \
   build.sh \
   compute-levels.sh \
   ca/build.sh \
-  ca/nix-copy.sh
+  ca/nix-copy.sh \
+  ca/substitute.sh
   # parallel.sh
 
 install-tests += $(foreach x, $(nix_tests), tests/$(x))

tests/push-to-store.sh

@@ -1,4 +1,6 @@
 #!/bin/sh
 
-echo Pushing "$@" to "$REMOTE_STORE"
-printf "%s" "$OUT_PATHS" | xargs -d: nix copy --to "$REMOTE_STORE" --no-require-sigs
+set -x
+
+echo Pushing "$OUT_PATHS" to "$REMOTE_STORE"
+printf "%s" "$DRV_PATH" | xargs nix copy --to "$REMOTE_STORE" --no-require-sigs