So, I will try and explain this to the best of my ability:
I wrote a TCP server that accepts data from a wearable (type of gps bracelet), using net in NodeJS. TCP server has connections = {} property, which contains all the connections, like this:
- Server accepts connection
- Device sends handshake packet, that contains
device id - Socket is stored like:
connections[device_id] = socket
Same TCP server also has express server which allows me to send data directly to the device using JSON post: curl -XPOST https://localhost:8080/send/device_id -d '{"command": "test"}'
Server parsers the url and writes to socket with connections[params.device_id].write()
This all works fine, when using pm2 start server.js. I am able to track devices, accept and send data, etc.
The issue is, when I start the server using pm2 start -i 5 server.js in cluster mode, device connections work okay, but express part is giving me issues.
For example: when I use curl -XPOST https://localhost:8080/send/device_id -d '{"command": "test"}' in 80% of the time, this will go to the wrong instance of server.js, because there are five copies of server.js running and each has express server, and since PM2 manages everything, my request will hit the tcp server where the given device_id is connect in 1 out of 5 times. The way I understand it, PM2 starts 5 instances of server.js and manages and balances the connections for tcp and express.
So, my question is, how should I manage this? Is there a way to tell PM2 to forward port 8080 to ALL running instances in a cluster? That way I could send single command to all instances, and in the instance, check if device_id is connected, and write to it's socket.
Is this possible, and if so, is it a good idea? If not, what is the right approach to this?
Hope I managed to explain
Regards
* EDIT *
It may not be clear from the initial question, but the socket in question is passed from net.createServer function, like
const net = require('net');
const PORT = 8181;
let connections = {}
const server = net.createServer((c) => {
//... device id parse
connections[device_id] = c;
});
server.listen(PORT, () => {
console.log('Server started on', PORT);
});
