getQueuedBuilds(): Handle dependent builds first

Dependencies

• [2] HHOMBU7G hydra-queue-runner: Implement timeouts
• [3] NJJ7H64S Very basic multi-threaded queue runner
• [4] C6HOMHZW Don't try to handle SIGINT
• [5] 24BMQDZA Start of single-process hydra-queue-runner
• [6] UQQ4IL55 Add a error type for "unsupported system type"
• [7] 2IQRXLWE Support cancelling builds
• [8] GKZN4UV7 Make the queue monitor more robust, and better debug output
• [9] FQQRJUO4 Mark builds as busy
• [10] YZAI5GQU Implement a database connection pool
• [11] N5O7VEEO Immediately abort builds that require an unsupported system type
• [12] ENXUSMSV Make concurrency more robust
• [13] IWB3F4Z6 Fail builds with previously failed steps early
• [14] 5AIYUMTB Basic remote building
• [15] 22LDPAIP Check non-runnable steps for unsupported system type

Change contents

• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 482
  [3.1741]→[3.1741:1798](∅→∅)
  − std::list<Build::ptr> newBuilds; // FIXME: use queue
  [3.1741]

  [3.1798]
  + std::multimap<Path, Build::ptr> newBuilds;
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 501
  [2.715]→[2.715:795](∅→∅)
  − std::cerr << build->id << " " << build->buildTimeout << std::endl;
• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 502
  [3.10057]→[3.2451:2491](∅→∅)
  − newBuilds.push_back(build);
  [3.10057]

  [3.2491]
  + newBuilds.emplace(std::make_pair(build->drvPath, build));
• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 506
  [3.10236]→[3.2508:2856](∅→∅)
  − /* Now instantiate build steps for each new build. The builder

  − threads can start building the runnable build steps right away,

  − even while we're still processing other new builds. */

  − for (auto & build : newBuilds) {

  − // FIXME: remove build from newBuilds to ensure quick destruction

  − // FIXME: exception handling
  [3.10236]

  [3.10351]
  + std::set<Step::ptr> newRunnable;

  + unsigned int nrAdded;

  + std::function<void(Build::ptr)> createBuild;
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 510
  [3.10352]

  [3.870]
  + createBuild = [&](Build::ptr build) {
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 512
  [3.970]

  [3.10473]
  + nrAdded++;
• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 525
  [3.10994]→[3.10994:11016](∅→∅)
  − continue;
  [3.10994]

  [3.11016]
  + return;
• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 528
  [3.11027]→[3.77:128](∅→∅)
  − std::set<Step::ptr> newSteps, newRunnable;
  [3.11027]

  [3.128]
  + std::set<Step::ptr> newSteps;
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 530
  [3.211]

  [3.3067]
  +

  + /* Some of the new steps may be the top level of builds that

  + we haven't processed yet. So do them now. This ensures that

  + if build A depends on build B with top-level step X, then X

  + will be "accounted" to B in doBuildStep(). */

  + for (auto & r : newSteps) {

  + while (true) {

  + auto i = newBuilds.find(r->drvPath);

  + if (i == newBuilds.end()) break;

  + Build::ptr b = i->second;

  + newBuilds.erase(i);

  + createBuild(b);

  + }

  + }
• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 558
  [3.273]→[3.273:295](∅→∅)
  − continue;
  [3.273]

  [3.295]
  + return;
• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 606
  [3.11403]→[3.1201:1232](∅→∅)
  − if (badStep) continue;
  [3.11403]

  [3.11435]
  + if (badStep) return;
• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 619
  [3.3558]→[3.1161:1275](∅→∅),[3.1275]→[3.361:442](∅→∅),[3.361]→[3.361:442](∅→∅)
  − printMsg(lvlChatty, format("added build %1% (top-level step %2%, %3% new steps, %4% new runnable steps)")

  − % build->id % step->drvPath % newSteps.size() % newRunnable.size());
  [3.3558]

  [3.10110]
  + printMsg(lvlChatty, format("added build %1% (top-level step %2%, %3% new steps)")

  + % build->id % step->drvPath % newSteps.size());
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 627
  [3.3806]

  [3.3806]
  + };

  +

  + /* Now instantiate build steps for each new build. The builder

  + threads can start building the runnable build steps right away,

  + even while we're still processing other new builds. */

  + while (!newBuilds.empty()) {

  + auto build = newBuilds.begin()->second;

  + newBuilds.erase(newBuilds.begin());

  +

  + newRunnable.clear();

  + nrAdded = 0;

  + createBuild(build);

  +
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 642
  [3.3915]

  [3.3915]
  + printMsg(lvlChatty, format("got %1% new runnable steps from %2% new builds") % newRunnable.size() % nrAdded);
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 1264
  [3.14778]→[2.1601:1616](∅→∅)
  − sleep(5);

  −