From: Tzafrir Cohen <[EMAIL PROTECTED]>
Date: Wed, 28 Feb 2007 22:28:32 +0200
On Wed, Feb 28, 2007 at 10:56:14AM -0800, Yuan LIU wrote:
> After testing some AGI's, I noticed several extra Asterisk processes.
An agi script is run by the same user running asterisk, but is not
"asterisk": it is a different program. What is the command name on those
scripts?
Those were asterisk processes run as root. (I don't use a special user -
should know better:-).
> They
> are not zombies, but can't be killed by safe_asterisk.
safe_asterisk attempts (poorly) to guard asterisk. Not really to guard
all of its child processes.
> Nor will they die
> when CLI issues stop now. Then I read that each AGI spawns a separate
> Asterisk process.
Huh? AGI? FastAGI?
Plain AGI. So Asterisk does not spawn children to handle AGI? I read from
some comments about Trixbox being all AGI, spawning Asterisk all the time,
etc.
> But all my AGI calls have apparently completed
> successfully. So there should be no reason for them to hang there.
>
> Several questions:
>
> 1) Under what conditions will an AGI hang a process? (My test scripts
are
> pretty simple, almost directly derived from agi-test.agi.)
An AGI may be an arbitrary subprocess. This subprocess can do basically
everything. If it really wants to, (or if it misbehaves in the "right"
way) it won't die.
Here's the script I tested:
#!/usr/bin/perl
# Receives a text string from channel, assigns to $ARGV[0]
# times out by $ARGV[1].
# USAGE: AGI(recvtext[,varname[,timeout]])
# default varname=recvtext, timeout=5000 ms
use strict;
$|=1;
# Setup some variables
my %AGI;
while(<STDIN>) {
chomp;
last unless length($_);
if (/^agi_(\w+)\:\s+(.*)$/) {
$AGI{$1} = $2;
}
}
# print STDERR "AGI Environment Dump:\n";
# foreach my $i (sort keys %AGI) {
# print STDERR " -- $i = $AGI{$i}\n";
# }
my $output = $ARGV[0]?$ARGV[0]:"recvtext";
my $timeout = $ARGV[1]?$ARGV[1]:5000; # default 5 sec
# print STDERR "3. Testing 'receive text' in $timeout...";
print "RECEIVE TEXT $timeout\n";
chomp (my $res = <STDIN>);
if ($res =~ /^200/) {
$res =~ /result=(-?\d+)/;
if (!length($1)) {
print STDERR "FAIL ($res)\n";
exit 1;
} else {
print STDERR "PASS ($1)\n";
$res =~ /\(([^)]+)/;
my $var = $1;
print "Set Variable $output \"$var\"\n";
}
} else {
print STDERR "FAIL (unexpected result '$res')\n";
exit 2;
}
# end of script
I didn't notice THIS script hanging. It was some time before I read the
comments about Trixbox, and I couldn't reliably reproduce this now. During
the tests, I was changing timing parameters so some script had to go through
timeouts in RECEIVE TEXT - from 4 sec to 6 sec, and end up receiving
nothing. But even in these cases, I could see from CLI that they completed.
> 2) How to detect run-away processes under 2.4 kernels? In this kernel,
> each thread clusters process space and it's very difficult to
distinguish
> them without killing the main process.
hmm, please attach the output of:
ps auxww | grep asterisk
Here's one snapshot:
root 18234 0.0 0.2 2252 1052 ? S Feb27 0:00 /bin/sh
/usr/sbin/safe_asterisk
root 18236 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18237 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18239 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18240 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18241 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18242 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18243 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18244 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18245 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18246 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18247 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18248 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18249 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18250 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18251 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18252 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18253 0.0 1.4 16608 7176 ? S Feb27 0:44
/usr/sbin/asterisk -vvvg
root 18254 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18255 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18256 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18257 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18258 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18259 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18260 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18261 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18262 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
root 18263 0.0 1.4 16608 7176 ? S Feb27 0:00
/usr/sbin/asterisk -vvvg
Again, I'm not sure if this list contains any run-away processes because I
couldn't reproduce the problem. At this time, the Asterisk under the 2.6
kernel (the one performed the test set with the Asterisk under 2.4 kernel)
does not display spurious Asterisk processes.
As the above showed, the AGI script is pretty simple, and a direct adaption
of agi-test.agi. I tried to feed it all kinds of inputs under a shell and
it wouldn't hang or die abnormally by itself. Of course, when I observed
those hanging processes (from the 2.6 kernel) the Asterisk had gone through
quite a bit of up time - and a few "restart now" cycles before that. So
they may not be AGI related.
Yuan Liu
> 3) Any practical way to detect them from inside Asterisk - e.g., do some
> check after each AGI call? All my AGISTATUS reports success. I could
use
> System() but isn't that cumbersome?
Write/use better code, I guess.
--
Tzafrir Cohen
icq#16849755 jabber:[EMAIL PROTECTED]
+972-50-7952406 mailto:[EMAIL PROTECTED]
http://www.xorcom.com iax:[EMAIL PROTECTED]/tzafrir
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