man Munin::Plugin::Pgsql (3): Base module for PostgreSQL plugins for Munin

SYNOPSIS

The Munin::Plugin::Pgsql module provides base functionality for all PostgreSQL Munin plugins, including common configuration parameters.

CONFIGURATION

All configuration is done through environment variables.

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.

Example

 [postgres_*]
    user postgres
    env.PGUSER postgres
    env.PGPORT 5433

WILDCARD MATCHING

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.

REQUIREMENTS

The module requires DBD::Pg to work.

TODO

Support for using psql instead of DBD::Pg, to remove dependency.

BUGS

No known bugs at this point.

AUTHOR

Magnus Hagander <[email protected]>, Redpill Linpro AB

COPYRIGHT/License.

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.

API DOCUMENTATION

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 'PostgreSQL'.
 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".
 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 occurrances of
                the string %%FILTER%% will be replaced with this string, and
                for each occurance 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.