Cannot attach debugger to VS Code using process._debugProcess

[TomasHubelbauer]

VS Code version: Code 1.25.0 (0f080e5, 2018-07-05T13:11:58.697Z)
OS version: Windows_NT x64 10.0.17134

I cannot seem to be able to attach a debugger to an existing instance of Code by executing process._debugProcess(<code-pid>) (which is a Windows version of kill -s SIGUSR1 <node-pid>) in a separate instance of Node.

The call succeeds (doesn't throw an error), but doesn't print out information like this:

Debugger listening on ws://127.0.0.1:9229/cf49bcfe-d922-4f89-b438-57755d254198
For help see https://nodejs.org/en/docs/inspector

The above lines are printed out upon successful attachment to other running Node processes.

Because this is not printed out, I cannot know what port and UUID to use to connect to the debugger using CDP.

When I run the above and then scan all open ports of 127.0.0.1 and issue http://127.0.0.1:<port>/json/list against all of them, I do not find any open port where this URL (which is the same as chrome://inspect) returns a list of targets containing a VS Code instance.

Is it possible to attach a debugger to an existing VS Code instance and connect to it using CDP?

[auchenberg]

@TomasHubelbauer Are you trying to debug an instance of VS Code itself or a Node process?

[TomasHubelbauer]

I am looking for a way to attach a debugger to either of the Electron's processes, main or rendered.

In main I could issue a code like this:

BrowserWindow.getFocusedWindow().capturePage(…);
// or
BrowserWindow.getAllWindows()[0].capturePage(…);

In rendered, I could issue a code like this:

const electron = require('electron');
electron.remote.getCurrentWindow().capturePage(image => {
  //electron.clipboard.writeImage(image);
  electron.clipboard.writeText(image.toDataURL());
});

Both should get me a successful result - the image capture of the Electron's window, which I can then save to a file and use further.

I have verified that placing the rendered code into VS Code DevTools of a running instance indeed produces correct Data URI. However, when I issue process._debugProcess(<code-pid>) against an existing VS Code PID, it doesn't seem to attach so I cannot use CDP to run Runtime.evaluate with the above code.

[auchenberg]

@TomasHubelbauer I'm still not sure whether you are trying to debug VS Code itself or another Electron app. We have a debugging recipe for how you can debug both the main and renderer process of Electron apps here: https://github.com/Microsoft/vscode-recipes/tree/master/Electron

In general for all Electron apps (including VS Code itself) it's not possible to put the process into debug mode via SIGUSR1. This is tracked here electron/electron#11287

[TomasHubelbauer]

I am trying to debug VS Code itself, not any other Electron app. I then switched to using a barebones Electron app first to make sure I have basic working repro, but I was not succeeding either which leads me to believe I should open this with Electron so I did: electron/electron#13580.

process._debugProcess is a Windows version of SIGUSR1 as mentioned in my first comment.