Expose logger implemtation to modules for testing

[Muhomorik]

Is this a feature relevant to companion itself, and not a module?

• I believe this to be a feature for companion, not a module

Is there an existing issue for this?

• I have searched the existing issues

Describe the feature

Hello,

I would like to log errors in my logic that is not related to companion and main problem is that logger (winston) is defined in companion itself.

There are two different logs

Companion log, is OK, because I am in "module code" then, creating presets, actions, etc and have access to InstanceBase.

Logging Logging works because module should be either mocked or initialized for tests to work (infrastructure tests).

Now, this is my module logs that I am talking about.

My logic, like API calls, are not by any way related to companion and do not require it (actually, don't want it in global tab).

Let's take example from Jest.

An ES6 Class Example

With logger, I want to abstract from console and write

import { logger } from '../../logger.js'

export default class SoundPlayer {
  constructor() {
    this.foo = 'bar';
  }

  playSoundFile(fileName) {
    logger.warn('Playing sound file' + fileName);
  }
}

And set log level once from module config in main.js

if (isDebug) {
    logger.level = 'debug'
} else {
    logger.level = 'error'
} 

This is problematic, because of logger dependency from module base.

I want to propose to declare logger (winston) "somewhere else" :) And let developers use it, instead of controller, will all functions and overloads.
When running as module, it should take default implementation with transports. Something like CompanionTransport and MyModuleTransport.

Basically, I want logger.js in my repo and use logger from there.

Probably, something like that
https://github.com/bitfocus/companion/blob/1b6dfc49a2816568f68f43bfe360d6bcd49817de/lib/Log/Controller.js#L95C13-L95C13

May be related:
bitfocus/companion#2420

LogController

Usecases

Development and debugging mostly.

[Julusian]

This is a little challenging to do because of the isolation used for the modules. Because there is no shared code or memory space, all communication is being done over IPC.
But it should be possible to expose a winston like logger object that could be used. Some care will need to be taken, as until the runEntrypoint() function in your main.js file is called, the logger object will send everything to a blackhole or the console, as ipc isnt setup by that point.

I think for this to happen it is going to require someone to make a PR, I am unlikely to do this myself. When I have wanted to do this, I have passed the main instance around, most likely typed as just the logging functions. While more effort, it works around this without being too messy.

The point in the code to setup the logger would be

companion-module-base/src/module-api/base.ts

Line 125 in 225ee5d

.
As that is in the constructor of the InstanceBase class, you could also do this entirely just within your module and get the same behaviour (although it would be setup a little bit later, after upgrade scripts have been run)

[Muhomorik]

Thank you for reply.
Yes, it can be hard to do with isolation and I am not sure if it is worth it.

What is the recommended way then?
I tried to add Winston to my module and it works, but only because it writes to console and companion threats it as logs.

Add custom transport like ToMemoryTransport and let it communicate to companion via IPC?