command pipe concatenated messages

[John P. Rouillard]

In message <3FE81E6D.6030202 at exponential-e.com>,
Jim Mozley writes:
>The issue I see is with multiple passive checks becoming concatenated, 
>so I end up with events like this:
>
>My service is Up Some description[1065056739]
>PROCESS_SERVICE_CHECK_RESULT:my-host:my-service:0:Some description.
>
>Where another passive check becomes part of the description field of the 
>previous check.
>
>I am using some perl code to submit commands containing:
>
>
>open(PIPE, "> $pipe") or croak "Cannot open pipe $!";

I would use ">> $pipe" to append data for two reasons:

  1 - > clobbers data already existing in files, not sure about in pipes
  2 - atomic writes occur only if file is opened for append IIRC.

>flock(PIPE, LOCK_EX);

This should guarantee only one process is accessing the file, but I
think you have already written to the file by using > in your open, so
there may be a race condition.

>print PIPE "$cmd";
># wait before releasing lock so we don't overlap cmds to Nagios
>sleep 2;
>close PIPE or croak "Cannot close pipe $!"; # also releases lock

				-- rouilj
John Rouillard
===========================================================================
My employers don't acknowledge my existence much less my opinions.


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