Pool local store connections

src/hydra-queue-runner/binary-cache-store.cc

@@ -234,11 +234,11 @@ void BinaryCacheStore::querySubstitutablePathInfos(const PathSet & paths,
     auto localStore = storeFactory();
 
     for (auto & storePath : paths) {
-        if (!localStore->isValidPath(storePath)) {
+        if (!(*localStore)->isValidPath(storePath)) {
             left.insert(storePath);
             continue;
         }
-        ValidPathInfo info = localStore->queryPathInfo(storePath);
+        ValidPathInfo info = (*localStore)->queryPathInfo(storePath);
         SubstitutablePathInfo sub;
         sub.references = info.references;
         sub.downloadSize = 0;
@@ -246,7 +246,7 @@ void BinaryCacheStore::querySubstitutablePathInfos(const PathSet & paths,
         infos.emplace(storePath, sub);
     }
 
-    localStore->querySubstitutablePathInfos(left, infos);
+    //(*localStore)->querySubstitutablePathInfos(left, infos);
 }
 
 void BinaryCacheStore::buildPaths(const PathSet & paths, BuildMode buildMode)
@@ -258,12 +258,12 @@ void BinaryCacheStore::buildPaths(const PathSet & paths, BuildMode buildMode)
 
         if (isValidPath(storePath)) continue;
 
-        localStore->addTempRoot(storePath);
+        (*localStore)->addTempRoot(storePath);
 
-        if (!localStore->isValidPath(storePath))
-            localStore->ensurePath(storePath);
+        if (!(*localStore)->isValidPath(storePath))
+            (*localStore)->ensurePath(storePath);
 
-        ValidPathInfo info = localStore->queryPathInfo(storePath);
+        ValidPathInfo info = (*localStore)->queryPathInfo(storePath);
 
         for (auto & ref : info.references)
             if (ref != storePath)

src/hydra-queue-runner/binary-cache-store.hh

@@ -5,6 +5,7 @@
 
 #include "lru-cache.hh"
 #include "sync.hh"
+#include "pool.hh"
 
 #include <atomic>
 
@@ -15,7 +16,8 @@ struct NarInfo;
 /* While BinaryCacheStore is thread-safe, LocalStore and RemoteStore
    aren't. Until they are, use a factory to produce a thread-local
    local store. */
-typedef std::function<ref<Store>()> StoreFactory;
+typedef Pool<nix::ref<nix::Store>> StorePool;
+typedef std::function<StorePool::Handle()> StoreFactory;
 
 class BinaryCacheStore : public Store
 {

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

@@ -18,6 +18,7 @@ using namespace nix;
 
 
 State::State()
+    : localStorePool([]() { return std::make_shared<ref<Store>>(openStore()); })
 {
     hydraData = getEnv("HYDRA_DATA");
     if (hydraData == "") throw Error("$HYDRA_DATA must be set");
@@ -26,9 +27,10 @@ State::State()
 }
 
 
-ref<Store> State::getLocalStore()
+StorePool::Handle State::getLocalStore()
 {
-    return openStore(); // FIXME: pool
+    auto conn(localStorePool.get());
+    return conn;
 }
 
 
@@ -733,10 +735,10 @@ void State::run(BuildID buildOne)
 #endif
 
     auto store = std::make_shared<S3BinaryCacheStore>(
-        []() { return openStore(); },
-        "/home/eelco/Misc/Keys/test.nixos.org/secret",
-        "/home/eelco/Misc/Keys/test.nixos.org/public",
-        "nix-test-cache-3");;
+        [this]() { return this->getLocalStore(); },
+        "/home/eelco/hydra/secret",
+        "/home/eelco/hydra/public",
+        "nix-test-cache");
     store->init();
     _destStore = store;
 

src/hydra-queue-runner/pool.hh

@@ -2,6 +2,7 @@
 
 #include <memory>
 #include <list>
+#include <functional>
 
 #include "sync.hh"
 
@@ -25,7 +26,14 @@
 template <class R>
 class Pool
 {
+public:
+
+    typedef std::function<std::shared_ptr<R>()> Factory;
+
 private:
+
+    Factory factory;
+
     struct State
     {
         unsigned int count = 0;
@@ -36,6 +44,10 @@ private:
 
 public:
 
+    Pool(const Factory & factory = []() { return std::make_shared<R>(); })
+        : factory(factory)
+    { }
+
     class Handle
     {
     private:
@@ -74,7 +86,7 @@ public:
         }
         /* Note: we don't hold the lock while creating a new instance,
            because creation might take a long time. */
-        return Handle(*this, std::make_shared<R>());
+        return Handle(*this, factory());
     }
 
     unsigned int count()

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

@@ -36,7 +36,7 @@ void State::queueMonitorLoop()
     unsigned int lastBuildId = 0;
 
     while (true) {
-        bool done = getQueuedBuilds(*conn, localStore, destStore, lastBuildId);
+        bool done = getQueuedBuilds(*conn, *localStore, destStore, lastBuildId);
 
         /* Sleep until we get notification from the database about an
            event. */

src/hydra-queue-runner/state.hh

@@ -16,6 +16,8 @@
 #include "store-api.hh"
 #include "derivations.hh"
 
+#include "binary-cache-store.hh" // FIXME
+
 
 typedef unsigned int BuildID;
 
@@ -346,6 +348,9 @@ private:
 
     std::atomic<time_t> lastDispatcherCheck{0};
 
+    /* Pool of local stores. */
+    nix::StorePool localStorePool;
+
     /* Destination store. */
     std::shared_ptr<nix::Store> _destStore;
 
@@ -356,7 +361,7 @@ private:
 
     /* Return a store object that can access derivations produced by
        hydra-evaluator. */
-    nix::ref<nix::Store> getLocalStore();
+    nix::StorePool::Handle getLocalStore();
 
     /* Return a store object to store build results. */
     nix::ref<nix::Store> getDestStore();