Ensure child processes are killed

[leifcr]

When running webpacker dev server under foreman or guard-process, the node child process can sometimes continue to run. This ensure the child process is killed.

To test, install foreman gem install foreman, then add this to a Procfile:

web: bundle exec rails server
webpacker: ./bin/webpack-dev-server

Run foreman start

Start a new terminal and run foreman stop, and ps aux | grep webpacker will sometimes show the child process continue in the background.

Hitting ctrl+c when running interactive with foreman terminates the command properly, while start/stop does not. Seems like SIGINT is captured by the child process, while SIGTERM is not.

[guilleiguaran]

I think we would need to research for "Windows-compatible" fix for this before of proceeding

Thanks for your contribution!!

[matthewd]

As it's currently using exec, the immediate "child" process takes over here. That would seem to make any handling of further processes a matter for that one (the real webpack-dev-server). Does that process not manifest the same problem if run directly?

[gauravtiwari]

@leifcr Actually never had this issue with foreman. Please could you add --watch-stdin or --stdin arg to binstub and see if the issue still persist?

cmdline = [DEV_SERVER_BIN, "--", "--progress", "--color", "--watch-stdin", "--config", DEV_SERVER_CONFIG] + ARGV

[leifcr]

I've tested more and found that the initial test app I created used Rails 5.1 0 + webpack 1.2, which has a bit different webpack-dev-server bin from PR #367.

PR #367 solves the problem by using yarn run webpack-dev-server, which also tracks child processes, and properly kills them.

Closing this, as the solution in #367 is merged.

@gauravtiwari, @matthewd and @guilleiguaran: Thanks for looking into this one