Request: Expose the browser ID when launching

[joelgriffith]

When launching Chrome (at 62) it prints the special "browser" target to connect to:

DevTools listening on ws://127.0.0.1:9222/devtools/browser/dce23e24-5a5b-4f89-a3f4-749d3ef70ea9

This target isn't exposed/discoverable anywhere else in the protocol due to this merge: https://chromium-review.googlesource.com/c/596719

It might be a good thing to expose to consumers so that they can attach to this special target and do commands at the browser-level

[paulirish]

Thanks for filing this. I looked into it and found that we have two options:

1. Chrome will now log this target to stderr on launch. Previous to this CL, we'd see something like this:

DevTools listening on 127.0.0.1:56296

and it now prints:

DevTools listening on ws://127.0.0.1:63126/devtools/browser/c07d6691-cfb8-4a88-9bff-a03ce85848ea

2. If chrome is launched with the remote-debugging-port=0, then it creates a DevToolsActivePort file in the user profile directory. (This doesn't happen if port is non-zero). It's contents are now both the port and the browser WS target URL:

56778
/devtools/browser/7ef11f4e-5c38-4111-8a7c-979703b95d00

We had plans to use Chrome's magic port=0 resolution already, so I'm thinking we'll do adopt the first option.

@joelgriffith As for exposing to users, how about the instance object (with the kill() method) gets a property called browserWs with this url?

[joelgriffith]

browserWs would be fantastic! Thanks!

[paulirish]

I have an impl nearly ready for this in https://github.com/GoogleChrome/lighthouse/compare/browserws

[devtools-bot]

This issue was moved to GoogleChrome/chrome-launcher#10