hydra-queue-runner: Handle status queries on the main thread

Dependencies

• [2] RQUAATWB Add status dump facility
• [3] CCHPYTCP hydra-queue-runner: Handle $HYDRA_DBI
• [4] ATJ54SPX Use PostgreSQL notifications for queue events
• [5] NJJ7H64S Very basic multi-threaded queue runner
• [*] 24BMQDZA Start of single-process hydra-queue-runner
• [*] C6HOMHZW Don't try to handle SIGINT
• [*] T2EIYJNG On SIGINT, shut down the builder threads

Change contents

• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 83
  [3.403]

  [3.403]
  + }

  + };

  +

  +

  + struct receiver : public pqxx::notification_receiver

  + {

  + bool status = false;

  + receiver(pqxx::connection_base & c, const std::string & channel)

  + : pqxx::notification_receiver(c, channel) { }

  + void operator() (const string & payload, int pid) override

  + {

  + status = true;

  + };

  + bool get() {

  + bool b = status;

  + status = false;

  + return b;
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 454
  [4.117]→[4.117:573](∅→∅)
  −

  − struct receiver : public pqxx::notification_receiver

  − {

  − bool status = false;

  − receiver(pqxx::connection_base & c, const std::string & channel)

  − : pqxx::notification_receiver(c, channel) { }

  − void operator() (const string & payload, int pid) override

  − {

  − status = true;

  − };

  − bool get() {

  − bool b = status;

  − status = false;

  − return b;

  − }

  − };
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 458
  [4.737]→[2.116:163](∅→∅)
  − receiver dumpStatus(*conn, "dump_status");
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 482
  [2.192]→[2.192:255](∅→∅)
  − if (dumpStatus.get())

  − State::dumpStatus();
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 1314
  [8.92]

  [9.771]
  +

  + while (true) {

  + try {

  + auto conn(dbPool.get());

  + receiver dumpStatus(*conn, "dump_status");

  + while (true) {

  + conn->await_notification();

  + if (dumpStatus.get())

  + State::dumpStatus();

  + }

  + } catch (std::exception & e) {

  + printMsg(lvlError, format("main thread: %1%") % e.what());

  + sleep(10); // probably a DB problem, so don't retry right away

  + }

  + }
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 1330
  [9.772]

  [4.3479]
  + // Never reached.