Chrome-remote-interface: How to resume Debugger when `--inspect-brk` ?

[atian25]

'use strict';

const CDP = require('chrome-remote-interface');
const cp = require('child_process');
const sleep = require('mz-modules/sleep');

async function fn() {
  let client;
  try {
    const child = cp.fork('./child', [], { execArgv: [ '--inspect-brk=9229' ] });
    await sleep('2s');
    console.log(child.connected && 'fork child');

    client = await CDP({ port: 9229 });

    const { Debugger } = client;
    console.log('attached');

    // pending at here
    await Debugger.enable();
    console.log('enabled');

    await Debugger.resume();
    console.log('resume');
  } catch (err) {
    console.error(err);
  } finally {
    console.log('close');
    if (client) {
      await client.close();
    }
  }
}

fn().catch(console.error);

child.js

console.log(1);
console.log(2);

output:

➜  cdp-test node index.js
Debugger listening on ws://127.0.0.1:9229/d23439a7-9607-43f2-93f3-d47e09dcd436
For help see https://nodejs.org/en/docs/inspector
fork child
attached

| Component | Version
|-|-
| Operating system | Mac
| Node.js | v8.5.0
| chrome-remote-interface | latest ^0.25.2

Is Chrome running in a container? NO

[cyrus-and]

You need to issue Runtime.runIfWaitingForDebugger before enabling the Debugger domain (see this wiki):

await Runtime.runIfWaitingForDebugger();
await Debugger.enable();

But after that you'll get Error: Can only perform operation while paused meaning that you should explicitly wait the debugger to be paused in order to resume it:

await Debugger.paused();
await Debugger.resume();

Hope it helps. Unfortunately this part is a bit contrived and scarcely documented. I suggest you to inspect DevTools (see "Sniffing the protocol") to figure out how things are implemented.

[atian25]

thanks