Add command ‘hydra-queue-runner --status’ to show current status

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

@@ -25,6 +25,7 @@
 #include "derivations.hh"
 #include "shared.hh"
 #include "globals.hh"
+#include "value-to-json.hh"
 
 using namespace nix;
 
@@ -256,12 +257,10 @@ private:
 public:
     State();
 
-    ~State();
-
-    void clearBusy(time_t stopTime);
-
 private:
 
+    void clearBusy(Connection & conn, time_t stopTime);
+
     void loadMachines();
 
     int createBuildStep(pqxx::work & txn, time_t startTime, Build::ptr build, Step::ptr step,
@@ -308,9 +307,13 @@ private:
     /* Thread that asynchronously bzips logs of finished steps. */
     void logCompressor();
 
+    void dumpStatus(Connection & conn);
+
 public:
 
-    void dumpStatus();
+    void showStatus();
+
+    void unlock();
 
     void run();
 };
@@ -325,17 +328,6 @@ State::State()
 }
 
 
-State::~State()
-{
-    try {
-        printMsg(lvlInfo, "clearing active builds / build steps...");
-        clearBusy(time(0));
-    } catch (...) {
-        ignoreException();
-    }
-}
-
-
 void State::loadMachines()
 {
     Path machinesFile = getEnv("NIX_REMOTE_SYSTEMS", "/etc/nix/machines");
@@ -381,10 +373,9 @@ void State::loadMachines()
 }
 
 
-void State::clearBusy(time_t stopTime)
+void State::clearBusy(Connection & conn, time_t stopTime)
 {
-    auto conn(dbPool.get());
-    pqxx::work txn(*conn);
+    pqxx::work txn(conn);
     txn.parameterized
         ("update BuildSteps set busy = 0, status = $1, stopTime = $2 where busy = 1")
         ((int) bssAborted)
@@ -1405,47 +1396,132 @@ void State::logCompressor()
 }
 
 
-void State::dumpStatus()
+void State::dumpStatus(Connection & conn)
 {
+    std::ostringstream out;
+
+    {
+        JSONObject root(out);
+        root.attr("status", "up");
+        root.attr("time", time(0));
+        root.attr("pid", getpid());
         {
             auto builds_(builds.lock());
-        printMsg(lvlError, format("%1% queued builds") % builds_->size());
+            root.attr("nrQueuedBuilds", builds_->size());
         }
         {
             auto steps_(steps.lock());
             for (auto i = steps_->begin(); i != steps_->end(); )
                 if (i->second.lock()) ++i; else i = steps_->erase(i);
-        printMsg(lvlError, format("%1% pending/active build steps") % steps_->size());
+            root.attr("nrUnfinishedSteps", steps_->size());
         }
         {
             auto runnable_(runnable.lock());
             for (auto i = runnable_->begin(); i != runnable_->end(); )
                 if (i->lock()) ++i; else i = runnable_->erase(i);
-        printMsg(lvlError, format("%1% runnable build steps") % runnable_->size());
+            root.attr("nrRunnableSteps", runnable_->size());
         }
-    printMsg(lvlError, format("%1% active build steps") % nrActiveSteps);
-    printMsg(lvlError, format("%1% build steps currently building") % nrStepsBuilding);
-    printMsg(lvlError, format("%1% builds read from queue") % nrBuildsRead);
-    printMsg(lvlError, format("%1% builds done") % nrBuildsDone);
-    printMsg(lvlError, format("%1% build steps done") % nrStepsDone);
-    printMsg(lvlError, format("%1% build step retries") % nrRetries);
-    printMsg(lvlError, format("%1% most retries for any build step") % maxNrRetries);
-    printMsg(lvlError, format("%1% queue wakeups") % nrQueueWakeups);
-    printMsg(lvlError, format("%1% dispatcher wakeups") % nrDispatcherWakeups);
-    printMsg(lvlError, format("%1% database connections") % dbPool.count());
+        root.attr("nrActiveSteps", nrActiveSteps);
+        root.attr("nrStepsBuilding", nrStepsBuilding);
+        root.attr("nrBuildsRead", nrBuildsRead);
+        root.attr("nrBuildsDone", nrBuildsDone);
+        root.attr("nrStepsDone", nrStepsDone);
+        root.attr("nrRetries", nrRetries);
+        root.attr("maxNrRetries", maxNrRetries);
+        root.attr("nrQueueWakeups", nrQueueWakeups);
+        root.attr("nrDispatcherWakeups", nrDispatcherWakeups);
+        root.attr("nrDbConnections", dbPool.count());
         {
+            root.attr("machines");
+            JSONObject nested(out);
             auto machines_(machines.lock());
             for (auto & m : *machines_) {
-            printMsg(lvlError, format("machine %1%: %2%/%3% active")
-                % m->sshName % m->currentJobs % m->maxJobs);
+                nested.attr(m->sshName);
+                JSONObject nested2(out);
+                nested2.attr("currentJobs", m->currentJobs);
+                nested2.attr("maxJobs", m->maxJobs);
             }
         }
+    }
+
+    {
+        pqxx::work txn(conn);
+        // FIXME: use PostgreSQL 9.5 upsert.
+        txn.exec("delete from SystemStatus where what = 'queue-runner'");
+        txn.parameterized("insert into SystemStatus values ('queue-runner', $1)")(out.str()).exec();
+        txn.exec("notify status_dumped");
+        txn.commit();
+    }
+}
+
+
+void State::showStatus()
+{
+    auto conn(dbPool.get());
+    receiver statusDumped(*conn, "status_dumped");
+
+    string status;
+    bool barf = false;
+
+    /* Get the last JSON status dump from the database. */
+    {
+        pqxx::work txn(*conn);
+        auto res = txn.exec("select status from SystemStatus where what = 'queue-runner'");
+        if (res.size()) status = res[0][0].as<string>();
+    }
+
+    if (status != "") {
+
+        /* If the status is not empty, then the queue runner is
+           running. Ask it to update the status dump. */
+        {
+            pqxx::work txn(*conn);
+            txn.exec("notify dump_status");
+            txn.commit();
+        }
+
+        /* Wait until it has done so. */
+        barf = conn->await_notification(5, 0) == 0;
+
+        /* Get the new status. */
+        {
+            pqxx::work txn(*conn);
+            auto res = txn.exec("select status from SystemStatus where what = 'queue-runner'");
+            if (res.size()) status = res[0][0].as<string>();
+        }
+
+    }
+
+    if (status == "") status = R"({"status":"down"})";
+
+    std::cout << status << "\n";
+
+    if (barf)
+        throw Error("queue runner did not respond; status information may be wrong");
+}
+
+
+void State::unlock()
+{
+    auto conn(dbPool.get());
+
+    clearBusy(*conn, 0);
+
+    {
+        pqxx::work txn(*conn);
+        txn.exec("delete from SystemStatus where what = 'queue-runner'");
+        txn.commit();
+    }
 }
 
 
 void State::run()
 {
-    clearBusy(0);
+    {
+        auto conn(dbPool.get());
+        clearBusy(*conn, 0);
+        dumpStatus(*conn);
+    }
 
     loadMachines();
 
@@ -1464,7 +1540,7 @@ void State::run()
             while (true) {
                 conn->await_notification();
                 if (dumpStatus.get())
-                    State::dumpStatus();
+                    State::dumpStatus(*conn);
             }
         } catch (std::exception & e) {
             printMsg(lvlError, format("main thread: %1%") % e.what());
@@ -1487,10 +1563,13 @@ int main(int argc, char * * argv)
         signal(SIGHUP, SIG_DFL);
 
         bool unlock = false;
+        bool status = false;
 
         parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
             if (*arg == "--unlock")
                 unlock = true;
+            else if (*arg == "--status")
+                status = true;
             else
                 return false;
             return true;
@@ -1503,8 +1582,10 @@ int main(int argc, char * * argv)
         /* FIXME: need some locking to prevent multiple instances of
            hydra-queue-runner. */
         State state;
-        if (unlock)
-            state.clearBusy(0);
+        if (status)
+            state.showStatus();
+        else if (unlock)
+            state.unlock();
         else
             state.run();
     });

src/sql/hydra.sql

@@ -531,6 +531,12 @@ create rule IdempotentInsert as on insert to FailedPaths
 #endif
 
 
+create table SystemStatus (
+    what text primary key not null,
+    status json not null
+);
+
+
 -- Cache of the number of finished builds.
 create table NrBuilds (
     what  text primary key not null,

src/sql/upgrade-34.sql

@@ -0,0 +1,4 @@
+create table SystemStatus (
+    what text primary key not null,
+    status json not null
+);