Function checkServer

src/sdam/monitor.ts:261–424

(monitor: Monitor, callback: Callback<Document | null>)

}

function checkServer(monitor: Monitor, callback: Callback<Document | null>) {
  let start: number;
  let awaited: boolean;
  const topologyVersion = monitor.server.description.topologyVersion;
  const isAwaitable = useStreamingProtocol(monitor, topologyVersion);
  monitor.emitAndLogHeartbeat(
    Server.SERVER_HEARTBEAT_STARTED,
    monitor.server.topology.s.id,
    undefined,
    new ServerHeartbeatStartedEvent(monitor.address, isAwaitable)
  );

  function onHeartbeatFailed(err: Error) {
    monitor.connection?.destroy();
    monitor.connection = null;
    monitor.emitAndLogHeartbeat(
      Server.SERVER_HEARTBEAT_FAILED,
      monitor.server.topology.s.id,
      undefined,
      new ServerHeartbeatFailedEvent(monitor.address, calculateDurationInMs(start), err, awaited)
    );

    const error = !(err instanceof MongoError)
      ? new MongoError(MongoError.buildErrorMessage(err), { cause: err })
      : err;
    error.addErrorLabel(MongoErrorLabel.ResetPool);
    if (error instanceof MongoNetworkTimeoutError) {
      error.addErrorLabel(MongoErrorLabel.InterruptInUseConnections);
    }

    monitor.emit('resetServer', error);
    callback(err);
  }

  function onHeartbeatSucceeded(hello: Document) {
    if (!('isWritablePrimary' in hello)) {
      // Provide hello-style response document.
      hello.isWritablePrimary = hello[LEGACY_HELLO_COMMAND];
    }

    // NOTE: here we use the latestRtt as this measurement corresponds with the value
    // obtained for this successful heartbeat, if there is no latestRtt, then we calculate the
    // duration
    const duration =
      isAwaitable && monitor.rttPinger
        ? (monitor.rttPinger.latestRtt ?? calculateDurationInMs(start))
        : calculateDurationInMs(start);

    monitor.addRttSample(duration);

    monitor.emitAndLogHeartbeat(
      Server.SERVER_HEARTBEAT_SUCCEEDED,
      monitor.server.topology.s.id,
      hello.connectionId,
      new ServerHeartbeatSucceededEvent(monitor.address, duration, hello, isAwaitable)
    );

    if (isAwaitable) {