Re: pipes, scripts, and launchd
Re: pipes, scripts, and launchd
- Subject: Re: pipes, scripts, and launchd
- From: Perry Smith <email@hidden>
- Date: Fri, 28 Dec 2007 20:31:03 -0600
I've been dinking with Unix since '82 but I've never played with named
pipes. I wrote a couple test scripts today and I think I can get that
to work.
Another related question: I saw one example launchd.plist file that
had two stanzas in it. Would that work?
(There seems to be a lot of mis-information about launchd files.)
Thank you for the suggestion,
pedz
On Dec 28, 2007, at 5:25 PM, Dave Zarzycki wrote:
I haven't tested this, but I suspect it should work...
Setup:
mkfifo /var/postgres_pipe
Job 1:
Have postgres write to /var/postgres_pipe via the launchd plist
StandardOutPath and StandardErrorPath keys.
Job 2:
#!/bin/sh
exec rotatelogs < /var/postgres_pipe
# Note to self: It would have been nice if launchd supported a
StandardInputPath configuration option
davez
On Dec 28, 2007, at 8:44 AM, Perry Smith wrote:
I may be making too big a deal of all this but I can't figure out
how to do something like:
postgres <args> | rotatelogs <args>
from launchd. If I put that command in a simple bash shell script,
I *believe* it will not work. The signal will go to bash and bash
will not pass it along to the children.
I could trap the signal and pass it along myself... but, $! gives
the pid for the last process in the pipe (rotatelogs). That is not
what I need to signal. I need the signal passed to postgres. And,
in fact, it would be nice if the signal did NOT pass to
rotatelogs. I'd like for it to stop when its input closes and not
before then.
I'm going to look in to using ksh and maybe using co-processes with
ksh. bash does not seem to have that concept. But, it just seems
like it should not be this hard to do.
Anyone have any suggestions of how to do this?
Thank you,
pedz
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