check_pg_streaming_replication

1) Nagios plugin to check Postgres Streaming replication
2) =====================================================
3) 
4) This script could be used as Nagios check plugin to verify Postgres Streaming
5) replication state.
6) 
7) This script :
8) 
9) - check if Postgres is running (CRITICAL raise if not)
10) - check if Postgres is in recovery mode :
11)   - if Postgres is in recovery mode :
12)     - retreive from Postgres the last xlog file receive and the xlog file replay
13)     - check if Postgres recovery configuration file is NOT present (CRITICAL
14)       raise if present)
15)     - retreive master connection informations from Postgres recovery configuration
16)       file (UNKNOWN raise on error). Default Postgres master TCP port will be used
17)       if port is not specify.

18)     - retreive current xlog file from Postgres master server by making a connection
19)       on master server (UNKNOWN raise on error).

20)     - check if the last receive xlog file is the last replay xlog file (WARNING raise if not)
21)     - Return OK state
22) - if Postgres is not in recovery mode :
23)   - check if Postgres recovery configuration file is present (CRITICAL raise if present)
24)   - check if stand-by client(s) is connected (WARNING raise if not)
25)   - Return OK state with list and count of stand-by client(s)
26) 

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

30) 

31) Requirements
32) ------------
33) 
34)  * On master node :
35) 

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

39) 
40)  * On standby node :
41) 

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

45) 
46) Usage
47) -----
48) 
49)     Usage : ./check_pg_streaming_replication [-h] [-d] [options]
50) 	-u pg_user		Specify Postgres user (Default : postgres)
51) 	-b psql_bin		Specify psql binary path (Default : /usr/bin/psql)
52) 	-m pg_main		Specify Postgres main directory path
53) 				(Default : /var/lib/postgresql/9.1/main)
54) 	-r recovery_conf	Specify Postgres recovery configuration file path
55) 				(Default : /var/lib/postgresql/9.1/main/recovery.conf)
56) 	-p pg_port		Specify default Postgres master TCP port (Default : 5432)

57) 	-D dbname		Specify DB name on Postgres hosts to connect on (Default : postgres)

58) 	-d			Debug mode
59) 	-h 			Show this message
60) 
61) Copyright
62) ---------
63) 

64) Copyright (c) 2017 Benjamin Renard