[Nagiosplug-devel] Please can I have GIT access

[Alain Williams]

On Fri, Sep 04, 2009 at 09:15:05AM -0400, Max wrote:
> On Fri, Sep 4, 2009 at 8:47 AM, Ton Voon<ton.voon at opsera.com> wrote:
> > So I think we should have a nagios plugins library called
> > np_write_state_data() and np_read_state_data().
> 
> that sounds good.
> 
> > What's the interface? Please help flesh this out. I'm guessing on a
> > write you would pass:
> >   * plugin name
> >   * optional index name for the state data (eg, hostname)
> >   * time of invocation
> >   * serialized data

We need a plugin_version number, since after upgrading a plugin the serialised
data might have changed. Perhaps this should be serialised_data_format_version.

Hmmm, I thought that I understood what that meant until I wondered how to use it.
You might need to consider that a plugin might be run several times on the same
machine - so what does 'index name' mean ?

check_procs can want to store about a process:
	pid ppid name MS secs
where	M is is the Metric (eg CPU%, virtual memory size, ...)
	S is the state (Critical or Warning)
It might have a Critical AND a Warning record for any particular process.

What I would like is to store/retrieve a blob (serialised string) that I can
then unserialise to my taste. It might be nice to provide serialisation routines,
this might be hard to generalise.

> Should we pass in time or should the write_state do that for the user
> so plugin developers do not have to repeat passing in time every time
> this is called?
> 
> > On a read, you pass:
> >   * plugin name
> >   * optional index name
> >
> > You get returned (null for error):
> >   * last time
> >   * serialized data
> 
> Would you return the last time or the number of seconds since the last
> write call?  Do I as a developer care about the real time or do I care
> about the interval between calls to write and read?  My personal
> preference and experience with plugins is that it is the interval
> between calls that matters, not the absolute timestamps.

In the case of my patch to check_procs what I am interested is the absolute
timestamp -- I want to know how long a process has been in a particular state.
I suspect that what this shows is that different plugins will want different
things.


-- 
Alain Williams
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