This post originated from an RSS feed registered with Ruby Buzz by Guy Naor. Original Post: Improving the rails spawner script Feed Title: Famundo - The Dev Blog Feed URL: http://devblog.famundo.com/xml/rss/feed.xml Feed Description: A blog describing the development and related technologies involved in creating famundo.com - a family management sytem written using Ruby On Rails and postgres Latest Ruby Buzz Posts Latest Ruby Buzz Posts by Guy Naor Latest Posts From Famundo - The Dev Blog

The spawner script in rails is pretty cool in that it will keep looking out for the FastCGI processes and make sure they are all working.

What I don't like about it, is that it launches the dispatcher again and again, letting it fail when the socket is already open. This is doing the unnecessary and puts more load on the system. But most of all it's just ugly!

As we're in a ruby script anyway, why not use it to see if the socket is in use before we launch the dispatcher? The only thing that needs to be changed is the spawn method (and you need to add a require 'socket' at the top of the script). We try to open a listening socket on the port we're being passed. If it opens, it means no process is listening on it and we can launch the dispatcher. If it is in use, an exception will be raised, and we just catch it, print a YES, and we're done.

def spawn(port)
  print "Checking if something is already running on port #{port}..."
  begin
    srv = TCPServer.new('0.0.0.0', port)
    srv.close
    srv = nil
    print "NO\n "
    print "Starting FCGI on port: #{port}\n  "
    system("#{OPTIONS[:spawner]} -f #{OPTIONS[:dispatcher]} -p #{port}")
  rescue
    print "YES\n"
  end
end

Now it will not even get to the dispatcher if the socket is already in use.