xref: /third_party/node/test/parallel/test-cluster-primary-error.js

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'use strict';
const common = require('../common');
const assert = require('assert');
const cluster = require('cluster');

const totalWorkers = 2;

// Cluster setup
if (cluster.isWorker) {
  const http = require('http');
  http.Server(() => {}).listen(0, '127.0.0.1');
} else if (process.argv[2] === 'cluster') {
  // Send PID to testcase process
  let forkNum = 0;
  cluster.on('fork', common.mustCall(function forkEvent(worker) {
    // Send PID
    process.send({
      cmd: 'worker',
      workerPID: worker.process.pid
    });

    // Stop listening when done
    if (++forkNum === totalWorkers) {
      cluster.removeListener('fork', forkEvent);
    }
  }, totalWorkers));

  // Throw accidental error when all workers are listening
  let listeningNum = 0;
  cluster.on('listening', common.mustCall(function listeningEvent() {
    // When all workers are listening
    if (++listeningNum === totalWorkers) {
      // Stop listening
      cluster.removeListener('listening', listeningEvent);

      // Throw accidental error
      process.nextTick(() => {
        throw new Error('accidental error');
      });
    }
  }, totalWorkers));

  // Startup a basic cluster
  cluster.fork();
  cluster.fork();
} else {
  // This is the testcase

  const fork = require('child_process').fork;

  // List all workers
  const workers = [];

  // Spawn a cluster process
  const primary = fork(process.argv[1], ['cluster'], { silent: true });

  // Handle messages from the cluster
  primary.on('message', common.mustCall((data) => {
    // Add worker pid to list and progress tracker
    if (data.cmd === 'worker') {
      workers.push(data.workerPID);
    }
  }, totalWorkers));

  // When cluster is dead
  primary.on('exit', common.mustCall((code) => {
    // Check that the cluster died accidentally (non-zero exit code)
    assert.strictEqual(code, 1);

    // XXX(addaleax): The fact that this uses raw PIDs makes the test inherently
    // flaky – another process might end up being started right after the
    // workers finished and receive the same PID.
    const pollWorkers = () => {
      // When primary is dead all workers should be dead too
      if (workers.some((pid) => common.isAlive(pid))) {
        setTimeout(pollWorkers, 50);
      }
    };

    // Loop indefinitely until worker exit
    pollWorkers();
  }));
}