How to integrate with SocketIO

[Alexandre Verri]

I'm trying to integrate the cls_hooked with SocketIO, using the Feathersjs framework:

const socketio = require('@feathersjs/socketio')
const tracer = require('../tracer')
const sync = require('feathers-sync')

module.exports = app => {
  // 'socket.feathers' is the same object as the connection
  // in a channel. 'socket.request' and 'socket.handshake' contains information
  // the HTTP request that initiated the connection.
  app.configure(socketio(io => {

    // https://docs.feathersjs.com/api/socketio.html#params
    io.use( (socket, next) => {
      tracer.run(() => {
        tracer.set('ip', socket.conn.remoteAddress)
        next()
      })
    })

  }))
}

The tracer.js:

const cls = require('cls-hooked')
const tracer = cls.createNamespace('app')
module.exports = tracer

... but the context is lost, it's not possible to get the 'ip' property from service functions.

[Pavan Patel]

@averri Any luck figuring out how to setup with feathers?

[Alexandre Verri]

Hi @ppatel890, unfortunately I have abandoned the use of cls-hooked, I have re-engineered the application code to do not rely on cls-hooked.

[Pavan Patel]

@averri - checking back in, any guidance on how you can have a requestId present throughout the entire socket 'request'?

[Alexandre Verri]

Hi @ppatel890, Nodejs 13 has a solution for this problem:
https://nodejs.org/docs/latest-v13.x/api/async_hooks.html#async_hooks_class_asynclocalstorage

In order to have a variable associated with the context of the current request it needs the support of AsyncLocalStorage in the SocketIO middleware.

The AsycLocalStorage has similar features of this library, so it's recommended to move to AsyncLocalStorage.

[Martin Alix]

Hi @ppatel890, Nodejs 13 has a solution for this problem: https://nodejs.org/docs/latest-v13.x/api/async_hooks.html#async_hooks_class_asynclocalstorage

In order to have a variable associated with the context of the current request it needs the support of AsyncLocalStorage in the SocketIO middleware.

The AsycLocalStorage has similar features of this library, so it's recommended to move to AsyncLocalStorage.

@averri This library already uses async_hooks on Node 8+