Rails - Dec 2005 - Independent thread use in Rails app

I would like to be able to start several independent threads in my
Rails app. These threads will run as long as the Rails app is running.

1) What is the right place to start and stop the threads? My threads
need to run shutdown  code.  I''ve tried adding code like this but it
isn''t working correctly. The debugger is getting an ABRT or TERM
signal and I still need to shut down the database.

Signal.trap("INT") { threads[0].kill; database.close; server.shutdown}
%w{ABRT CLD TERM STOP QUIT}.each { |x| Signal.trap(x) {
database.close; server.shutdown } }

threads[0].kill this is the monitor thread, it will never exit unless
killed. Alternatively I could send it a message to exit.

2) I''d like to set things up so that if WEBrick is being used the
threads run in the same process. But if lighttpd is being used with
multiple processes the thread only gets started in one of the fastcgi
processes.  There needs to be some mechanism to see if the process
with the thread dies and get it started again in another fastcgi
process.

The thread monitors the directory tree being served, if files are
copied in or removed it add/deletes them from a search database. It is
using iNotify on Linux, but other OSes offer similar monitoring APIs.
I''ll make the code public as soon as it is working, unless someone
tells me this has already been written.

--
Jon Smirl
jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org

> I would like to be able to start several independent threads in my
> Rails app. These threads will run as long as the Rails app is running.
A lot of folks have worked on this sort of thing before, and the  
general consensus has been that you make your life much easier by  
spinning off the threads into a standalone tasks that communicate  
with the Rails app using DRb or another RPC mechanism. This will free  
you from worrying about the thread/fork/etc. architectures of your  
chosen server model (WEBrick, mod_ruby, FCGI runners, etc.).

There''s a good introduction to DRb at http://segment7.net/projects/ 
ruby/drb/introduction.html.

-Ben