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Munin::Plugin::Pgsql − Base module for PostgreSQL plugins for Munin
The Munin::Plugin::Pgsql module provides base functionality for all PostgreSQL Munin plugins, including common configuration parameters.
All configuration is done through environment variables.
All plugins based on Munin::Plugin::Pgsql accepts all the environment variables that libpq does. The most common ones used are:
PGHOST hostname
to connect to, or path to Unix socket
PGPORT port number to connect to
PGUSER username to connect as
PGPASSWORD password to connect with, if a password is
required
The plugins will by default connect to the ’template1’ database, except for wildcard per-database plugins. This can be overridden using the PGDATABASE variable, but this is usually a bad idea.
If you are using plugin for several postgres instances, you can customize graph title with the environment variable PGLABEL.
Warning and critical can be customized by setting "warning" and "critical" env variables per plugin.
Example
[postgres_*]
user postgres
env.PGUSER postgres
env.PGPORT 5433
[postgres_connections_ALL]
env.warning :450
env.critical :500
Wildcard plugins based on this module will match on whatever type of object specifies for a filter, usually a database. If the object name ALL is used (for example, a symlink to postgres_connections_ALL), the filter will not be applied, and the plugin behaves like a non-wildcard one.
The module requires DBD::Pg to work.
Support for using psql instead of DBD::Pg, to remove dependency.
No known bugs at this point.
DBD::Pg
Magnus Hagander <magnus@hagander.net>, Redpill Linpro AB
Copyright (c) 2009 Magnus Hagander, Redpill Linpro AB
All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 dated June, 1991.
The following functions are available to plugins using this module.
Initialization
use Munin::Plugin::Pgsql;
my $pg = Munin::Plugin::Pgsql−>new(
parameter=>value,
parameter=>value
);
Parameters
minversion
Minimum PostgreSQL version required, formatted like 8.2. If
the
database is an older version than this, the plugin will exit
with an error.
category The category for this plugin. Copied directly to
the config
output. Default 'db'.
title The title for this plugin. Copied directly to the
config output.
info The info for this plugin. Copied directly to the config
output.
vlabel The vertical label for the graph. Copied directly to
the config
output.
basename For wildcard plugins, this is the base name of the
plugin,
including the trailing underscore.
basequery SQL query run to get the plugin values. The query
should return
two columns, one being the name of the counter and the
second
being the current value for the counter.
pivotquery Set to 1 to indicate that the query in basequery
returns a single
row, with one field for each counter. The name of the
counter is
taken from the returned column name, and the value from the
first row in the result.
configquery SQL query run to generate the configuration
information for the
plugin. The query should return at least two columns, which
are
the name of the counter and the label of the counter. If
a third column is present, it will be used as the info
parameter.
suggestquery SQL query to run to generate the list of
suggestions for a
wildcard plugin. Don't forget to include ALL if the plugin
supports aggregate statistics.
autoconfquery SQL query to run as the last step of
"autoconf", to determine
if the plugin should be run on this machine. Must return a
single
row, two columns columns. The first one is a boolean field
representing yes or no, the second one a reason for
"no".
warning The warning low and/or high thresholds.
critical The critical low and/or high thresholds.
graphdraw The draw parameter for the graph. The default is
LINE1.
graphtype The type parameter for the graph. The default is
GAUGE.
graphperiod The period for the graph. Copied directly to the
config output.
graphmin The min parameter for the graph. The default is no
minimum.
graphmax The max parameter for the graph. The default is no
maximum.
stack If set to 1, all counters except the first one will be
written
with a draw type of STACK.
base Used for graph_args −−base. Default is
1000, set to 1024 when
returning sizes in Kb for example.
wildcardfilter The SQL to substitute for when a wildcard
plugin is run against
a specific entity, for example a database. All occurrences
of
the string %%FILTER%% will be replaced with this string, and
for each occurrence a parameter with the value of the
filtering
condition will be added to the DBI statement.
paramdatabase Makes the plugin connect to the database in
the first parameter
(wildcard plugins only) instead of 'template1'.
defaultdb Makes the plugin connect to the database specified
in this
parameter instead of 'template1'.
extraconfig This string is copied directly into the
configuration output
when the plugin is run in config mode, allowing
low−level
customization.
postprocess A function that's called with the result of the
base query,
and can post−process the result and return a new
resultset.
postconfig A function that's called with the result of the
config query,
and can post−process the result and return a new
resultset.
postautoconf A function that's called with the result of the
autoconf query,
and can post−process the result and return a new
resultset.
postsuggest A function that's called with the result of the
suggest query,
and can post−process the result and return a new
resultset.
Specifying queries
Queries
specified in one of the parameters above can take one of two
forms. The easiest one is a simple string, which will then
always be executed, regardless of server version. The other
form is an array, looking like this:
[
" SELECT ’default’,...
FROM ...",
[
"8.3", " SELECT ’query
for 8.3 or earlier’,... FROM ...",
"8.1", " SELECT ’query
for 8.1 or earlier’,... FROM ..."
]
] This array is parsed from top to bottom, so the entries
must be in order of version number. The *last* value found
where the version specified is higher than or equal to the
version of the server will be used (yes, it counts
backwards).
Processing
$pg−>Process();
This command executes the plugin. It will automatically
parse the ARGV array
for commands given by Munin.