Does node js worker thread and rabbitmq consumer are same? - node.js

Question

This is to gain more knowledge on how rabbitmq queuing and node js master/worker threads combined.

Answer 1

Node.js master worker threads are different then rabbitmq queuing as rabbitmq provides the facility to store the tasks into queue so that they can be consumed by a worker process when a worker is free. Combining these two would have very specific use cases and generally not needed.
There are couple of things required for the combined implementation of these two which mainly includes node-amqp client and cluster. Cluster is the default feature of node which provides the api for master worker threads. Without rabbitmq you would generally distribute the tasks using one master process i.e. send the task to all worker process and worker threads listens to receive the tasks.
Now since you want to use rabbitmq you have to first subscribe to a exchange to listen for all the tasks and when you receive the task you pass that to your worker process. Below is an small snippet to provide the gist of explaination.
connection.on('ready', function() {
connection.exchange('exchange-name', function(exchange) {
_exchange = exchange;
connection.queue('queue-name', function(queue) {
_queue = queue;
// Bind to the exchange
queue.bind('exchange-name', 'routing-key');
// Subscribe to the queue
queue
.subscribe(function(message) {
// When receiving the message call the worker thread to complete the task
console.log('Got message', message);
queue.shift(false, false);
})
.addCallback(function(res) {
// Hold on to the consumer tag so we can unsubscribe later
_consumerTag = res.consumerTag;
})
;
});
});
});
Message exchange between master and worker: Instead of directly sending message to master worker needs to put the success message to a queue. The master will listen to that queue to receive the acknowledgements and success messages.