debugging - How to debug a rails (3.2) app started by foreman?

Question

I am trying to use foreman to start my rails app. Unfortunately I have difficulties connecting my IDE for debugging.

I read here about using

Debugger.wait_connection = true
Debugger.start_remote

to start a remote debugging session, but that does not really work out.

Question: Is there a way to debug a rails (3.2) app started by foreman? If so, what is the approach?

Answer 1

If you use several workers with full rails environment you could use the following initializer:

# Enabled debugger with foreman, see https://github.com/ddollar/foreman/issues/58
if Rails.env.development?
  require 'debugger'
  Debugger.wait_connection = true

  def find_available_port
    server = TCPServer.new(nil, 0)
    server.addr[1]
  ensure
    server.close if server
  end

  port = find_available_port
  puts "Remote debugger on port #{port}"
  Debugger.start_remote(nil, port)
end

And in the foreman's logs you'll be able to find debugger's ports:

$ foreman start
12:48:42 web.1     | started with pid 29916
12:48:42 worker.1  | started with pid 29921
12:48:44 web.1     | I, [2012-10-30T12:48:44.810464 #29916]  INFO -- : listening on addr=0.0.0.0:5000 fd=10
12:48:44 web.1     | I, [2012-10-30T12:48:44.810636 #29916]  INFO -- : Refreshing Gem list
12:48:47 web.1     | Remote debugger on port 59269
12:48:48 worker.1  | Remote debugger on port 41301

Now run debugger using:

rdebug -c -p [PORT]