Example of how to exchange messages between node processes

exchange-message-between-node-process.js

// Sending messages
if (cluster.isMaster) {
  // It's also possible to get workers by iterating over `cluster.workers` hash map:
  // https://nodejs.org/api/cluster.html#cluster_cluster_workers
  const worker = cluster.fork();
  worker.send('Sending message to worker');
} else {
  process.send('Sending message to master');
}

// Receiving messages
if (cluster.isMaster) {
  const worker = ... // getting a worker
  worker.on('message', fromWorker => { /* handle worker's message */ });
} else {
  process.on('message', fromMaster => { /* handle master's message */ })
}