Bad File Descriptor in Ruby Daemons

Question

Using Ruby v1.8.7 and Daemons v1.1.8 on Mac OS X Lion, I am attempting to write a consumer process and get it run as a dameon:

# config[:name] => 'idx_my_delete_consumer'
# config[:daemon] => {:multiple => false,
#                    :backtrace => true, 
#                    :dir_mode => :normal, 
#                    :log_dir => '/Users/pprakash/consumer.log',
#                    :monitor => true,
#                    :dir => '/Users/pprakash/pids'}

 Daemons.run_proc(config[:name], config[:daemon]) do
    consumer = MyConsumer.new(config)  
    consumer.subscribe
  end

However, it does not start and instead throws a long traceback, which goes something like this:

E, [2012-05-28T19:34:16.199770 #29357] ERROR -- : Bad file descriptor (Errno::EBADF)
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/daemonize.rb:134:in `for_fd'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/daemonize.rb:134:in `close_io'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/daemonize.rb:134:in `initialize'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/daemonize.rb:134:in `new'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/daemonize.rb:134:in `close_io'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/daemonize.rb:75:in `call_as_daemon'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/application.rb:258:in `start_proc'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/application.rb:295:in `start'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:51:in `watch'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:51:in `fork'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:51:in `watch'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:45:in `each'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:45:in `watch'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:44:in `loop'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:44:in `watch'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:84:in `start_with_pidfile'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:64:in `fork'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:64:in `start_with_pidfile'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/monitor.rb:111:in `start'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/application_group.rb:149:in `create_monitor'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/application.rb:284:in `start'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/controller.rb:70:in `run'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons.rb:197:in `run_proc'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/cmdline.rb:109:in `call'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons/cmdline.rb:109:in `catch_exceptions'
/opt/local/lib/ruby/gems/1.8/gems/daemons-1.1.8/lib/daemons.rb:196:in `run_proc'
users/delete_consumer.rb:40

I am not sure what is causing this issue? The directory name, log file name are all valid. I am able to create an instance of MyConsumer with these config and able to execute its #subscribe properly from a standalone program/console.

Answer 1

Based on my experiences with Ruby Daemons, I found that such errors indicate that the underlying block (which is daemonized) contains errors. Fixing those errors fixes this error as well.