[Nagios-checkins] SF.net SVN: nagios:[2386] nagioscore/trunk/docs/queryhandlers.dox

[<ag...@us...>]

Revision: 2386
          http://nagios.svn.sourceforge.net/nagios/?rev=2386&view=rev
Author:   ageric
Date:     2012-10-22 10:33:27 +0000 (Mon, 22 Oct 2012)
Log Message:
-----------
Add docs/queryhandlers.dox

Probably incomplete. I wrote it a while back and it's been lying
around ever since. It's got some info though, and there isn't
really all that much to say about them, so this will probably
suffice.

Signed-off-by: Andreas Ericsson <ae...@op...>

Added Paths:
-----------
    nagioscore/trunk/docs/queryhandlers.dox

Added: nagioscore/trunk/docs/queryhandlers.dox
===================================================================
--- nagioscore/trunk/docs/queryhandlers.dox	                        (rev 0)
+++ nagioscore/trunk/docs/queryhandlers.dox	2012-10-22 10:33:27 UTC (rev 2386)
@@ -0,0 +1,68 @@
+/** @page qh Query Handler
+
+@section purpose Purpose
+The purpose of the query handler is to provide Nagios Core and its
+eventbroker modules with the ability to communicate directly with
+the outside world through a well-defined API, as well as allowing
+external apps a way to help out with various Nagios tasks.
+
+@section caveats Caveats
+The query handlers run in the main thread. Nagios doesn't provide any
+parallellism here and main Nagios will be blocked while a query is
+running. As such, it's a very good idea to make ones queryhandlers
+complete in as little time as possible.
+
+@section syntax Syntax
+The query language is remarkably simple (although each handler may
+implement its own parsers that handle and do pretty much whatever
+they want).
+
+Basically, it boils down to an at-sign, followed by a (registered)
+address, followed by a space, followed by free-form text (which the
+query-handler at that address will take care of parsing), followed
+by a nul byte.
+
+It looks like this:
+@verbatim
+@<address><SPACE><query-for-the-handler>
+@endverbatim
+
+So to send a query to the echo service, it would look something like
+this:
+@verbatim
+@echo Hello there, Nagios :)
+@endverbatim
+
+@section icqh In-core query handlers
+There are a few in-core query handlers.
+
+@subsection echo The echo service
+As I'm sure you've already guessed, the echo service just prints the
+inbound data right back at you. While that's not exactly nobel prize
+winning material, it's actually pretty nifty to figure out how fast
+Nagios can parse its inbound data, which in turn shows how fast it can
+handle its inbound checkresults, which puts an upper cap on how many
+checks Nagios can handle at any given time (although short bursts that
+exceed that limit are ok and will be handled just fine).
+
+It can be addressed as such:
+@verbatim
+@echo foo bar baz said the bunny\0
+@endverbatim
+
+@subsection nerd Nagios Event Radio Dispatcher
+The nerd radio is subscribed in fuller detail at @see nerd, but its
+worth knowing that it's a core part of Nagios 4 and that it will
+always be available.
+
+@subsection wproc Worker process manager
+The worker process manager lets you register workers that can help out
+with running checks, send notifications, run eventhandlers or whatever.
+
+In order to register a worker that only handles checks supposed to be
+run by the plugins check_foo and check_bar (irrespective of where in
+the paths they are), you'd do something like this:
+@verbatim
+@wproc register name=foobar\nplugin=check_foo\nplugin=check_bar\n\0
+@endverbatim
+*/

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