ByeBug remote won't hit breakpoints with Unicorn

Question

I launch unicorn through foreman, so the debugger prompt is swallowed. I've had luck with the debugger gem in the past connecting as a remote debugger.

We're about to upgrade to Ruby 2.1.2 which, as I understand it, is not compatible with debugger.

I've changed the remote debugger code to use byebug:

require 'byebug'

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}"
Byebug.start_server('localhost', port)

Once unicorn is started, I can connect to byebug:

$ byebug -R localhost:54623
Connecting to byebug server localhost:54623
Connected.

But my code is littered with byebug calls, and they never trigger a breakpoint in the remote debugger. Pages that block on load when the debugger is not remote load normally when connected remotely.

The unicorn file specifies only one worker, so I'm reasonably sure that's not it:

require File.dirname(__FILE__)+'/application'

if Rails.env.development?
  worker_processes 1
  timeout_override = ENV['WEBSERVER_TIMEOUT_OVERRIDE']
  timeout Integer(timeout_override || 3600)
  if timeout_override
    puts "Development: Using WEBSERVER_TIMEOUT_OVERRIDE of #{timeout_override} seconds"
  end
else
  worker_processes Integer(ENV['WEB_CONCURRENCY'] || 3)
  timeout 25
end

preload_app true

before_fork do |server, worker|

  Signal.trap 'TERM' do
    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
    Process.kill 'QUIT', Process.pid
  end

  defined?(ActiveRecord::Base) and
      ActiveRecord::Base.connection.disconnect!
end

after_fork do |server, worker|

  Signal.trap 'TERM' do
    puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to send QUIT'
  end

  defined?(ActiveRecord::Base) and
      ActiveRecord::Base.establish_connection
end

Any ideas would be greatly appreciated.

score 1 · Answer 1 · answered Dec 21 '14 at 08:07

I think you missed one simple setting: Byebug.wait_connection = true

Change this

port = find_available_port
puts "Remote debugger on port #{port}"
Byebug.start_server('localhost', port)

to this

port = find_available_port
puts "Remote debugger on port #{port}"
Byebug.wait_connection = true
Byebug.start_server('localhost', port)

This should do the magic. Hope it helps.

ByeBug remote won't hit breakpoints with Unicorn

1 Answers1