From f57d0b0c54684231e7a49f14a334db7d94287159 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Thu, 18 Jun 2015 00:24:56 +0200
Subject: [PATCH] hydra-queue-runner: Maintain count of active build steps

---
 src/hydra-queue-runner/build-remote.cc       |  2 ++
 src/hydra-queue-runner/hydra-queue-runner.cc | 11 +++++++++++
 2 files changed, 13 insertions(+)

diff --git a/src/hydra-queue-runner/build-remote.cc b/src/hydra-queue-runner/build-remote.cc
index f0adccf5..39529e1a 100644
--- a/src/hydra-queue-runner/build-remote.cc
+++ b/src/hydra-queue-runner/build-remote.cc
@@ -39,6 +39,8 @@ static void openConnection(const string & sshName, const string & sshKey,
         if (dup2(stderrFD, STDERR_FILENO) == -1)
             throw SysError("cannot dup stderr");
 
+        // FIXME: ensure no password prompt.
+        // FIXME: connection timeouts
         Strings argv({"ssh", sshName, "-i", sshKey, "-x", "-a", "--", "nix-store", "--serve", "--write"});
 
         execvp("ssh", (char * *) stringsToCharPtrs(argv).data()); // FIXME: remove cast
diff --git a/src/hydra-queue-runner/hydra-queue-runner.cc b/src/hydra-queue-runner/hydra-queue-runner.cc
index aae081b4..417c5202 100644
--- a/src/hydra-queue-runner/hydra-queue-runner.cc
+++ b/src/hydra-queue-runner/hydra-queue-runner.cc
@@ -39,6 +39,13 @@ bool has(const C & c, const V & v)
 
 typedef std::atomic<unsigned int> counter;
 
+struct MaintainCount
+{
+    counter & c;
+    MaintainCount(counter & c) : c(c) { c++; }
+    ~MaintainCount() { c--; }
+};
+
 
 typedef enum {
     bsSuccess = 0,
@@ -229,6 +236,7 @@ private:
     counter nrBuildsRead{0};
     counter nrBuildsDone{0};
     counter nrStepsDone{0};
+    counter nrActiveSteps{0};
     counter nrRetries{0};
     counter maxNrRetries{0};
     counter nrQueueWakeups{0};
@@ -957,6 +965,8 @@ void State::builder(Step::ptr step, MachineReservation::ptr reservation)
 {
     bool retry = true;
 
+    MaintainCount mc(nrActiveSteps);
+
     try {
         auto store = openStore(); // FIXME: pool
         retry = doBuildStep(store, step, reservation->machine);
@@ -1252,6 +1262,7 @@ void State::dumpStatus()
             if (i->lock()) ++i; else i = runnable_->erase(i);
         printMsg(lvlError, format("%1% runnable build steps") % runnable_->size());
     }
+    printMsg(lvlError, format("%1% active build steps") % nrActiveSteps);
     printMsg(lvlError, format("%1% builds read from queue") % nrBuildsRead);
     printMsg(lvlError, format("%1% builds done") % nrBuildsDone);
     printMsg(lvlError, format("%1% build steps done") % nrStepsDone);