[PATCH] Fix default value for enable_environment_macros

[Paul Dubuc]

Daniel Wittenberg wrote:
>
> On Jan 11, 2013, at 11:08 AM, Andreas Ericsson wrote:
>
>> On 01/11/2013 02:43 PM, Ton Voon wrote:
>>>
>>> On 11 Jan 2013, at 12:17, Andreas Ericsson wrote:
>>>
>>>> On 01/10/2013 11:31 PM, Ton Voon wrote:
>>>>> However, even with this set to true, it looks like Nagios 4 doesn't
>>>>> set the envvars. In host/service checks, it looks like no envvars
>>>>> are set. Is there a technical reason why this is not done, or is
>>>>> this a bug?
>>>>>
>>>>
>>>> The technical reason is twofold: I'm lazy, and environment macros
>>>> cause a lot of additional problems for anything but very small
>>>> systems, while providing a mediocre benefit at best.
>>>>
>>>> The problem people have been seeing with Nagios 3 where certain
>>>> checks fail to run when they add an extra service to a servicegroup
>>>> is due to environment macros being enabled and the environment space
>>>> being eaten.
>>>>
>>>> To enable them again means transferring the entire environment to the
>>>> designated worker process, parsing it from there and setting it in a
>>>> new heap which we pass to execvpe().
>>>>
>>>> Since we will always pay *all* overhead for all checks but very, very
>>>> few of them use more than one or two of the variables set, the
>>>> benefit really isn't worth the additional overhead.
>>>
>>> I think this "bug" is a blocker for upgrading to Nagios 4 since certain
>>> checks/notification scripts/event handlers expect the environment
>>> variables to be set.'
>
> Really?  I can't think of the last time I ran into a setup that the only
> way to use a check/script was as environment variables.  It's way more
> efficient, and I think easier, to just pass the few params you normally
> need as command-line options.  Even for things like Oracle I just set local
> env options in the script or use one of the scripts that lets you pass in
> what ORACLE_HOME and stuff should be.
>

I set enable_environment_macros to 0 to avoid the overhead mentioned.  For 
command that need environment variables set, we put them in the command object 
definition.  For example, setting LD_LIBRARY_PATH:

define command{
     command_name    gatewayTest
     command_line    \
         LD_LIBRARY_PATH=$USER31$/omni/$_SERVICE_OMNI_VERSION$/lib \
         $USER32$/bin/gatewayTest \
         -S $SERVICEDESC$ -t $_SERVICE_TIMEOUT$ \
         $ARG1$ $ARG2$ $ARG3$ $ARG4$ $ARG5$ $ARG6$
}

Will this not work in Nagios 4?

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