Fix a race that can cause hydra-queue-runner to ignore newly added builds

Dependencies

• [2] OG3Z3QGC Namespace cleanup
• [3] H4KMCXGU Use triggers for all notifications on Builds table changes
• [4] MHVIT4JY Split hydra-queue-runner.cc more
• [5] RVHBV3B3 Notify the queue runner when a build is deleted
• [6] PHX2HIVG * Store info about the build inputs in the build record.
• [7] ZK76B5ZZ Load the queue in order of global priority
• [8] 73YR46NJ hydra-queue-runner: Write directly to a binary cache
• [9] HJOEIMLR Refactor
• [10] RND7XFNH getQueuedBuilds(): Periodically stop to handle priority bumps
• [11] DKJFD6JN Process Nix API changes
• [12] WE5Q2NVI Allow build to be bumped to the front of the queue via the web interface
• [*] N22GPKYT * Put info about logs / build products in the DB.
• [*] TJK27WSB Open the DB using Hydra::Model::DB->new
• [*] WQXF2T3D hydra-evaluator: Don't require $HYDRA_CONFIG
• [*] DDGBLKEN Update isCurrent properly
• [*] DDMYFZ5X Fix the jobset unchanged check
• [*] D5QIOJGP * Move everything up one directory.

Change contents

• replacement in src/hydra-queue-runner/queue-monitor.cc at line 51
  [4.21027]→[4.21027:21058](∅→∅)
  − if (buildsAdded.get())
  [4.21027]

  [4.21058]
  + if (auto lowestId = buildsAdded.get()) {

  + lastBuildId = std::stoi(*lowestId) - 1;
• edit in src/hydra-queue-runner/queue-monitor.cc at line 54
  [4.21145]

  [4.21145]
  + }
• replacement in src/hydra-queue-runner/queue-monitor.cc at line 80
  [4.21622]→[4.21622:21709](∅→∅)
  − printMsg(lvlInfo, format("checking the queue for builds > %1%...") % lastBuildId);
  [4.21622]

  [4.21709]
  + printInfo("checking the queue for builds > %d...", lastBuildId);
• replacement in src/libhydra/db.hh at line 24
  [5.626]→[5.626:679](∅→∅)
  − struct receiver : public pqxx::notification_receiver
  [5.626]

  [5.679]
  + class receiver : public pqxx::notification_receiver
• replacement in src/libhydra/db.hh at line 26
  [5.681]→[5.681:706](∅→∅)
  − bool status = false;
  [5.681]

  [5.706]
  + std::experimental::optional<std::string> status;

  +

  + public:

  +
• edit in src/libhydra/db.hh at line 32
  [5.829]

  [2.216]
  +
• replacement in src/libhydra/db.hh at line 35
  [5.898]→[5.898:921](∅→∅)
  − status = true;
  [5.898]

  [5.921]
  + status = payload;
• replacement in src/libhydra/db.hh at line 37
  [5.928]→[5.928:1012](∅→∅)
  − bool get() {

  − bool b = status;

  − status = false;

  − return b;
  [5.928]

  [5.1012]
  +

  + std::experimental::optional<std::string> get() {

  + auto s = status;

  + status = std::experimental::nullopt;

  + return s;
• edit in src/script/hydra-eval-jobset at line 28
  [15.745]

  [16.961]
  + my $notifyAdded = $db->storage->dbh->prepare("notify builds_added, ?");

  +
• edit in src/script/hydra-eval-jobset at line 725
  [17.51]

  [18.518]
  +

  + # Wake up hydra-queue-runner.

  + my $lowestId;

  + while (my ($id, $x) = each %buildMap) {

  + $lowestId = $id if $x->{new} && (!defined $lowestId || $id < $lowestId);

  + }

  + $notifyAdded->execute($lowestId) if defined $lowestId;

  +
• edit in src/sql/hydra.sql at line 236
  [3.1]→[3.1:210](∅→∅),[3.210]→[5.135:136](∅→∅),[5.135]→[5.135:136](∅→∅)
  − create function notifyBuildsAdded() returns trigger as 'begin notify builds_added; return null; end;' language plpgsql;

  − create trigger BuildsAdded after insert on Builds execute procedure notifyBuildsAdded();

  −
• file addition: upgrade-54.sql (----------)
  [19.3004]
  + drop trigger BuildsAdded on Builds;

  + drop function notifyBuildsAdded();