Nagios plugin to check Postgres Streaming replication
=====================================================

This script could be used as Nagios check plugin to verify Postgres Streaming
replication state.

This script :

- check if Postgres is running (CRITICAL raise if not)
- check if Postgres is in recovery mode :
  - if Postgres is in recovery mode :
    - retreive from Postgres the last xlog file receive and the xlog file replay
    - check if Postgres recovery configuration file is NOT present (CRITICAL
      raise if present)
    - retreive master connection informations from Postgres recovery configuration
      file (UNKNOWN raise on error). Default Postgres master TCP port will be used
      if port is not specify.
    - retreive current xlog file from Postgres master server by making a connection
      on master server (UNKNOWN raise on error).
    - check if the last receive xlog file is the last replay xlog file (WARNING raise if not)
    - Return OK state
- if Postgres is not in recovery mode :
  - check if Postgres recovery configuration file is present (CRITICAL raise if present)
  - check if stand-by client(s) is connected (WARNING raise if not)
  - Return OK state with list and count of stand-by client(s)

Note : This script was originally write for PostgreSQL 9.1 and test on 9.1 and 9.5 but it
could be compatible with other versions of PostgreSQL. Do not hesitate to tell me how this
script work with other versions and share some fix. All contributions are welcome !

Requirements
------------

 * On master node :

     Slaves must be able to connect with user from recovery.conf to database with
     the same name (or another specify with -D) as trust (or via md5 using password
     specify in ~/.pgpass).

 * On standby node :

     PG_USER must be able to connect localy on the database with the same name
     (or another specify with -D) as trust (or via md5 using password specify in
     ~/.pgpass).

Usage
-----

    Usage : ./check_pg_streaming_replication [-h] [-d] [options]
	-u pg_user		Specify Postgres user (Default : postgres)
	-b psql_bin		Specify psql binary path (Default : /usr/bin/psql)
	-m pg_main		Specify Postgres main directory path
				(Default : /var/lib/postgresql/9.1/main)
	-r recovery_conf	Specify Postgres recovery configuration file path
				(Default : /var/lib/postgresql/9.1/main/recovery.conf)
	-p pg_port		Specify default Postgres master TCP port (Default : 5432)
	-D dbname		Specify DB name on Postgres hosts to connect on (Default : postgres)
	-d			Debug mode
	-h 			Show this message

Copyright
---------

Copyright (c) 2017 Benjamin Renard

License
-------

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License version 2
as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.