How to start multiple watchers with correct output style with prefix in each output?

[mortyccp]

Context

In a project that contains sdk and app and app depends on sdk and both are javascript that need to be built.
In local development, when developing the app in hot reload, would expect the sdk to also start in watch mode too.
To simulate, create the following tasks for testing.

# https://moonrepo.dev/docs/config/project
$schema: 'https://moonrepo.dev/schemas/project.json'

language: 'javascript'
stack: 'frontend'
type: 'application'
dependsOn:
  - 'sdk'

tasks:
  all:
    command: noop
    deps:
      - 'ping'
      - 'pong'
    options:
      persistent: true
      outputStyle: stream

  ping:
    script: 'while true; do echo ping; sleep 1; done'
    options:
      persistent: true
      outputStyle: stream
    deps: 
      - 'pong'

  pong:
    script: 'while true; do echo pong; sleep 1; done'
    options:
      persistent: true
      outputStyle: stream
  
  all-watcher-preset:
    preset: 'watcher'
    command: noop
    deps:
      - 'ping-watcher-preset'
      - 'pong-watcher-preset'

  ping-watcher-preset:
    preset: 'watcher'
    script: 'while true; do echo ping; sleep 1; done'
    deps: 
      - 'pong-watcher-preset'

  pong-watcher-preset:
    preset: 'watcher'
    script: 'while true; do echo pong; sleep 1; done'

  # invalid:
  #   command: 'noop'
  #   options:
  #     persistent: true
  #     interactive: true

Results

1. Start a noop tasks that depends on both tasks. Outputs are prefixed correctly.

2. Start the task that depends on another task. The started task output is not prefixed.

3. Set with preset: 'watcher'. Start a noop tasks that depends on both tasks. Outputs are not prefixed.

4. Set with preset: 'watcher'. Start the task that depends on another task. Outputs are not prefixed.

6. Can't manually set persistent: true and interactive: true which should be the same withpreset: 'watcher'

Questions

1. What's the suggested way to achieve start both watchers with proper prefixed output?
2. Why can't manually set persistent: true and interactive: true?

[milesj]

If you only run a single task, the output of that task is not prefixed, while others are. When running multiple tasks, they are all prefixed.

Task options have nothing to do with prefixing.

[milesj]

All of these examples are running 1 task, and by that I mean, through moon run. So moon run app:all, moon run app:ping, etc, are all just 1 task. The task deps do not count. Here's the logic: https://github.com/moonrepo/moon/blob/master/crates/task-runner/src/command_executor.rs#L313

Those watcher tasks are weird though. I'd expect them to be prefixed. I wonder if it's because they are script and not command.

[mortyccp]

If both moon run app:all and moon run app:ping are consider running 1 task. Then why the output of moon run app:all is prefixed for app:ping and app:ping ? The output of moon run app:ping also has prefix for app:ping but not the task that initially run app:ping 🤔

Updated to use command for the watcher tasks, still not prefixed.
And why interactive and persistent can only be set with watcher preset but not explicitly with options?

[milesj]

I figured it out. So when something is interactive, we print directly to stdout/stderr without passing through moon: https://github.com/moonrepo/moon/blob/master/crates/task-runner/src/command_executor.rs#L116

That's why prefixes are lost.

And why interactive and persistent can only be set with watcher preset but not explicitly with options?

This is also a weird edge case that probably shouldn't be allowed. We need better logic here.

The issue is that if you're running multiple persistent tasks in parallel (which happens a lot), they can't be interactive, because where would stdin go?

[mortyccp]

Make sense. Then what's the reason for preset: watcher to be interactive ?

[milesj]

I think that's just an oversight.