if-selection does not handle exit codes correctly in generic_proc module

if-selection does not handle exit codes correctly in generic_proc module - Printable Version

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if-selection does not handle exit codes correctly in generic_proc module - thomas - 11-10-2017

I'm trying to do something similar to the ICMP Checks in https://wiki.pandorafms.com/index.php?title=Pandora:Documentation_en:Operations section 1.7.1
but the outcome of module_exec does not show up as expected in the FMS Console. Running the command locally does indeed work.

The manual gives this example:

Code:
module_begin

module_name Ping

module_type generic_proc

module_exec ping -c 1 192.168.100.54 >/dev/null 2>&1; if [ $? == 0 ]; then echo 1; else echo 0; fi

module_end

My intallation is base on pandorafms.agent_unix_7.0NG.714.deb, pandorafms.console_7.0NG.714.deb and pandorafms.server_7.0NG.714.deb

Excerpt from my /etc/pandora/pandora_agent.conf, where I've cleaned up the configuration to make the bug more obvious:

Code:
module_begin

module_name Always 0

module_type generic_proc

module_exec echo 0

module_end

module_begin

module_name Always 1

module_type generic_proc

module_exec echo 1

module_end

module_begin

module_name Always 0 complicated

module_type generic_proc

module_exec false; if [ $? == 0 ]; then echo 1; else echo 0; fi

module_end

module_begin

module_name Always 1 complicated

module_type generic_proc

module_exec true; if [ $? == 0 ]; then echo 1; else echo 0; fi

module_end

Running the commands manually in the shell works as expected:

$ echo 0
0

$ echo 1
1

$ false; if [ $? == 0 ]; then echo 1; else echo 0; fi
0

$ true; if [ $? == 0 ]; then echo 1; else echo 0; fi
1

But, the FMS Console shows:

Always 0
0
Always 1
1
Always 0 complicated
0
Always 1 complicated
0

Thus it seems like the if-selection does not work when running in the Pandora Agent, but it works when running from the command line.

RE: if-selection does not handle exit codes correctly in generic_proc module - thomas - 11-10-2017

Code:
module_begin

module_name Simple 0

module_type generic_proc

module_exec true; echo $?

module_end

module_begin

module_name Simple 1

module_type generic_proc

module_exec false; echo $?

module_end

Using the shell:

$ true; echo $?
0

$ false; echo $?
1

And the FMS Console shows:

Simple 0
0

Simple 1
1

This works as expected. (But it is of course not what I want to do.)

RE: if-selection does not handle exit codes correctly in generic_proc module - vic - 11-13-2017

Hi thomas,

Can you try to create a module with this configuration?

Code:
module_begin

module_name Ping

module_type generic_proc

module_exec ping 192.168.70.127 -c 1 |grep "1 received" | wc -l

module_end

If the check is correct, it will show a "1".

Best regards,

vic.

RE: if-selection does not handle exit codes correctly in generic_proc module - thomas - 11-13-2017

Let's try to find out if it is something special with the $? variable!

Code:
module_begin

module_name Always 0 fool it again

module_type generic_proc

module_exec a=1;  if [ $a == 0 ]; then echo 1; else echo 0; fi

module_end

module_begin

module_name Always 1 fool it again

module_type generic_proc

module_exec a=0;  if [ $a == 0 ]; then echo 1; else echo 0; fi

module_end

Using the shell:
$ a=1; if [ $a == 0 ]; then echo 1; else echo 0; fi
0
$ a=0; if [ $a == 0 ]; then echo 1; else echo 0; fi
1

The Pandora FMS Console:
Always 0 fool it again
0
Always 1 fool it again
0

It seems I can't even get an ordinary variable to work inside the if-clause.

RE: if-selection does not handle exit codes correctly in generic_proc module - thomas - 11-13-2017

I believe that I have solved the problem.

Using -eq instead of == makes the example given in the manual work.

Code:
module_begin

module_name Ping

module_type generic_proc

module_exec ping -c 1 192.168.100.54 >/dev/null 2>&1; if [ $? -eq 0 ]; then echo 1; else echo 0; fi

module_end

RE: if-selection does not handle exit codes correctly in generic_proc module - vic - 11-14-2017

Hi thomas,

It seems that you are correct, I have modified the wiki, so that it doesn't happen again.
Thanks for reporting.

Best regards,

vic.