Group prefix/suffix

[romulof]

Use-case

I'm trying to output a line before and after each command, to use Github Actions log grouping.

Concurrently's group option helps a lot, but it lacks an API to print stuff before and after.

Problem

There is no API to print stuff before and after commands.

In my use-case I only need 1 process, so I hacked my way around the start of the commands and when they are closed:

import { endGroup, startGroup } from '@actions/core';
import { GITHUB_ACTIONS } from 'ci-info';
import { concurrently } from 'concurrently';

// ...

const result = concurrently(commands, {
  raw: true,
  group: true,
  maxProcesses,
});

if (GITHUB_ACTIONS && maxProcesses === '1') {
  result.commands.forEach((command) => {
    if (command.state === 'started') {
      // Commands immediately started after calling concurrently()
      startGroup(command.name);
    } else {
      // Commands started later
      const originalStart = command.start.bind(command);
      command.start = () => {
        // Start is called before previous command close is called, so we need
        // to defer the start of the group until the close event is received.
        setTimeout(() => {
          startGroup(command.name);
        }, 0);
  
        return originalStart();
      };
    }
    command.close.subscribe(() => {
      endGroup();
    });
  });
}

Proposal

Extend group definition to allow prefix and suffixes:

import { endGroup, startGroup } from '@actions/core';
import { GITHUB_ACTIONS } from 'ci-info';
import { concurrently } from 'concurrently';

//...

concurrently(commands, {
  raw: true,
  group: {
    prefix: '::group::{name}',
    suffix: '::endgroup::',
  },
  maxProcesses,
});

Would also be nice to have an API to be informed when commands have started.