From: Rogue Amateur <rogueamateur@...>
Date: 2006-07-14T04:50:14+09:00
Subject: Re: Nuby Q: Daemonize (other materials have been read!)

unknown wrote:
> On Fri, 14 Jul 2006, Rogue Amateur wrote:
> 
>>
>> So, this works.  So does another, innocuous script I wrote.  I even
>> checked out the daemonize library the other person suggested, and it
>> works too.  My pain in the butt actually need it to work as a daemon,
>> however, does not work.
>>
>> What could cause code which works in interactive mode to fail in daemon
>> mode?
>>
>> I'm checking the code now, and I do have "if debug" statements which
>> output to STDOUT.  Could that be the problem?
> 
> only unless you need them to go somewhere - the code i sent has them 
> going to
> /dev/null.
> 
>> I'm adding some blurbs to try to get the stupid thing to tell me, but it
>> seems to die so silently (eg: nothing in syslog, which is where most
>> messages are expected to go), that I can't get enough information.
>>
>> I know it manages to send the "shut down the listener" message, which is
>> a "rescue" action.
> 
> well - then it must be throwing an error right?  post you code and i'm 
> sure
> someone will spot the error.
> 
>> Hints, suggestions and other comments?
> 
> wrap your script with this
> 
>    begin
> 
>      #
>      # your entire script
>      #
> 
>    rescue Exception => e
>      require 'tmpdir'
> 
>      tmp = Dir.tmpdir
>      this = File.basename $0
>      pid = Process.pid
> 
>      deathlog = File.join tmp, "#{ this }.#{ pid }"
> 
>      m, c, b = e.message, e.class, e.backtrace.join("\n")
> 
>      msg = "%s (%s)\n%s" % [m, c, b]
> 
>      open(deathlog, "w"){|f| f.puts msg}
>    end
> 
> after it runs do an
> 
>    ls -ltar /tmp
> 
> there should should find a record of the failure.
> 
> 
> regards.
> 
> 
> -a

I'd love to post the code, but I can't - it's proprietary.  If I can 
rewrite it so that I cna post it, I will do so tonight.  Basically, I'll 
have to rewrite it, and verify that the rewrite has the same problem.

truely odd things are happening:
   daemon.rb my_code.rb > with your Exception recue clause returned 
nothing.  Executes Listener stop.
   ruby daemon.rb my_code.rb > with the exception clause returns 
nothing.  However, it doesn't execute the Listener stop either.
   (using daemonize inside the code)
   my_code.rb > with exception clause returns 2 files (1503 and 1502, 
both of which say:
      exit (SystemExit)
      /usr/lib/site_ruby/1.8/daemonize.rb:26:in `exit'
      /usr/lib/site_ruby/1.8/daemonize.rb:26:in `daemonize'
      ./my_code.rb:621
      **** repeat the run, and new files are not created.

   I'm not seeing any errors logged to syslog, or my verbose log.

ONCE, I seemed to get it to work.  I ran it as a plain run in a redirect 
to /dev/null, and then killed the window.  It killed that process, but 
didn't kill the listener.  Then, I ran it with "ruby daemon.rb 
my_code.rb" (no daemonize inside the code)., and it worked, and ran 
through to completion.  I have not been able to do that again!

will work on rewriting tonight, and posting.  apologies for the 
stupidity.

RA

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