Run chrome as a part of lighthouse cli

I’ve been trying some stuff with finding chrome and spawning it as a part of CLI.

lighthouse <url>

1. When connection fails to Remote Debugger, try launch chrome
2. osx - find chrome and if there is more than 1 installation, use inquirer to let user select
3. I don’t know how to tell when chrome remote-debugger is ready since I don’t get any message or event that tells it’s ready. So I poll(every 100ms) from the parent process(CLI) to connect to remote debugger and when it succeeds, we know that the remote-debugger is ready, then do lighthouse run.
4. Poll for fixed number of retries and then reject when it crosses the retry limit.
5. Kill chrome once everything is over - Only the chrome launched from the CLI is killed - not the one already running.

Ported shell scripts to JS for finding and launching chrome. The code is here - https://github.com/GoogleChrome/lighthouse/compare/master...boopathi:launch-chrome-js

Need some ideas and thoughts around this before I send a PR. Is this approach okay ? or do we want to keep running chrome as a separate foreground process?

Also, just curious, is there any other way to know that the remote-debugger has started when launched as a child process (instead of polling the port every 100ms)?

[paulirish]

fwiw: @wwchen of the devtools team just wrote a little module along these lines: https://codereview.chromium.org/2337713002/ see launch_chrome.js

It’s a little different as it only wants canary or chromium, but maybe theres something in there to steal. (Though admittedly the earlier patches here look pretty nice already 😃

[hemanth]

(Edited by paulirish. removed the gif cuz it creeped me out, sorry! 😃

Heh heh, no problem!

Nice on there with launch_chrome was planning to use exude 😇