From: ara.t.howard@...
Date: 2006-07-14T00:30:55+09:00
Subject: Re: Nuby Q: Daemonize (other materials have been read!)

On Fri, 14 Jul 2006, Rogue Amateur wrote:

> unknown wrote:
>> On Wed, 12 Jul 2006, Rogue Amateur wrote:
>>
>>>>
>>>
>
> [snip]
>
>>    fortytwo :~ > daemon sleep 42
>>
>
> 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
-- 
suffering increases your inner strength.  also, the wishing for suffering
makes the suffering disappear.
- h.h. the 14th dali lama