Run the watcher on a Thread when Rails boots instead of foreman ?

[b-nik]

Hello,

This is a idea for an alternative way to run the dartsass watcher without using foreman. I didn't start with a PR to add this because maybe it has some disadvantages I'm unaware of, or it might be unwanted.

So, instead of foreman, I changed my Rails config.ru file to spawn a thread that runs the dartsass watcher instead:

require_relative "config/environment"

if Rails.env.development?
  dart_watcher_thread = Thread.new { system("./bin/rails dartsass:watch") }
  at_exit { dart_watcher_thread.exit }
end

run Rails.application
Rails.application.load_server

For me, this offers a few advantages:

1. No foreman dependency
2. Terminal debugging (i.e. pry) still works
3. Running ./bin/rails server is enough - this is minor, but probably removes some friction for people coming into dartsass and having to now change their usual start server command.

This feels like a better way, but of course I could be missing something. Thoughts?

[dhh]

Yeah, we're exploring this for tailwind css as well. We need a generic solution that ships in Rails to do this, though. But I think there's a good chance we can do this. See rails/tailwindcss-rails#347 for more discussions on this.