zmq.js

const { Publisher, Subscriber } = require('zeromq');

const PORT = 5000;

const args = process.argv.slice(2);

const TOPIC = args[0] || 'doc1';

let n = 0;

const publisher = async () => {
	const pub = new Publisher();

	await pub.bind(`tcp://127.0.0.1:${PORT}`);

	console.log(`Publisher bound to port ${PORT}`);

	while (n < 10) {
		console.log('sending');

		const msg = {
			instanceId: process.pid,
			content: 'hello'
		};

		await pub.send([TOPIC, JSON.stringify(msg)]);

		await new Promise(resolve => setTimeout(resolve, 500));

		n++;
	}
};

const subscriber = async () => {
	const sub = new Subscriber();

	sub.connect(`tcp://127.0.0.1:${PORT}`);

	sub.subscribe(TOPIC);

	console.log(`Subscriber connected to port ${PORT}`);

	for await (const [topic, msgBuf] of sub) {
		const msg = JSON.parse(msgBuf.toString());

		if (msg.instanceId !== process.pid) {	
			console.log(`received update for ${topic}:`, msg.content);
		}
	}
};

const main = async () => {
	try {
		subscriber();

		publisher();
	} catch (err) {
		console.log(err);

		process.exit(1);
	}
};


main();