Output of forked process not piped to debugger

[VentyCZ]

• Version: v10.13.0 (also present on v8.11.3)
• Platform: Windows 10 (64bit) (Also tested on Debian 9)

When using --inspect(-brk), the output of the child_process.forked script is not sent to the attached debugger.

I tried multiple options of stdio for child_process.fork function, all to no avail.

Test case

index.js

// Warning: if ran with --inspect(-brk) option, the wroker output (stdio) is NOT piped to the debugger
require('child_process').fork(`${__dirname}/worker.js`, [], {
    // Filter out the inspector/debugger options, so the debugger works properly
    execArgv: process.execArgv.filter((arg) => !arg.startsWith('--inspect'))
});

setInterval(() => {
    // This is going to be printed out to the debugger!
    console.log('Main script message!');
}, 1000);

worker.js

setInterval(() => {
    // This is NOT going to be printed out to the debugger!
    console.log('Worker message!');
}, 1000);

Test case result

All you can see in the Chrome DevTools Console is 'Main script message' written every second, but not the message from the worker (forked process). But all the output is written to the process stdout (after running node --inspect-brk index.js).

Expected result

The output written to the debugger should be the same as the stdout.

[VentyCZ]

Is it possible to pass the child process output to the already attached debugger, or should I use a separate debugger for the child process (I just need to see the log output) ?

[VentyCZ]

As of now, the current workaround is as follows (IPC communication still works after the stdio option changes):

index.js

// Warning: if ran with --inspect(-brk) option, the wroker output (stdio) is NOT piped to the debugger
// https://github.com/nodejs/node/issues/24295
let wk = require('child_process').fork(`${__dirname}/worker.js`, [], {
    // Filter out the inspector/debugger options, so the debugger works properly
    execArgv: process.execArgv.filter((arg) => !arg.startsWith('--inspect')),
    stdio: 'pipe'
});

wk.stdout && wk.stdout.on('data', (data) => {
    console.log(data.toString().trim());
});

wk.stderr && wk.stderr.on('data', (data) => {
    console.error(data.toString().trim());
});

[targos]

I think that is not possible without your workaround (or using the experimental Worker Threads API).

[bnoordhuis]

Duplicate of #9435, which is still unresolved as of this writing. See the discussion in that issue, it's basically around the pros and cons of the workaround you posted.