From 0ea1a4eac9b1719d0986af5b8cdc01ce70c7c2d1 Mon Sep 17 00:00:00 2001
From: n <n@tourmentine.com>
Date: Tue, 14 May 2019 11:22:04 +0200
Subject: [PATCH] check_postgresql_replication.sh

---
 README.md                                  |  2 +-
 monitoring/check_postgresql_replication.sh | 46 ++++++++++++++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100755 monitoring/check_postgresql_replication.sh

diff --git a/README.md b/README.md
index 86e1d36..bd612c1 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,6 @@ Scripts
   * [secupdate](https://forge.tourmentine.com/n/scripts/src/master/secupdate) => apply security updates & recompile kernel (FreeBSD)
   * [superscreen](https://forge.tourmentine.com/n/scripts/src/master/superscreen) => open multiple ssh sessions to a bunch of servers inside a screen
   * [zfsync.sh](https://forge.tourmentine.com/n/scripts/src/master/zfsync.sh) => sync some ZFS pools between two machines
-  * [pivotroot.sh](https://forge.tourmentine.com/n/scripts/src/master/pivotroot.sh) => pivot root to tmpfs on a live server in order to wipe it
 
 Greasemonkey/Userscripts
 ------------------------
@@ -36,6 +35,7 @@ Monitoring
 
   * [check_ntppool_score](https://forge.tourmentine.com/n/scripts/src/master/monitoring/check_ntppool_score) => Simple shell script to check score on NTP Pool Project (score must be over 10 to serve NTP). Requires Curl and bc, fits for Nagios/Shinken/Icinga/etc.
   * [collectd_ntppool_score](https://forge.tourmentine.com/n/scripts/src/master/monitoring/collectd_ntppool_score) => Same as [check_ntppool_score](https://forge.tourmentine.com/n/scripts/src/master/monitoring/check_ntppool_score) but for collectd graphing.
+  * [check_postgresql_replication.sh](https://forge.tourmentine.com/n/scripts/src/master/monitoring/check_postgresql_replication.sh) => check postgresql's replication lag.
   * [GonKyrellM](https://forge.tourmentine.com/n/scripts/src/master/monitoring/GonKyrellM) => Conky, GKrellM style - with "invisible" theme (well, sort of)
 
 Attic
diff --git a/monitoring/check_postgresql_replication.sh b/monitoring/check_postgresql_replication.sh
new file mode 100755
index 0000000..824838a
--- /dev/null
+++ b/monitoring/check_postgresql_replication.sh
@@ -0,0 +1,46 @@
+#!/bin/sh
+# check postgresql (streaming) replication
+# tested with postgresql 11.3 on FreeBSD 11.2
+#
+# pg_hba.conf access should be set to trust
+# warning (-w) and critical (-c) thresholds can be set in seconds
+# on a low trafic server don't hesitate to set them to a high value
+ 
+args=`getopt hw:c: $*`
+set -- $args
+
+warning=600
+critical=3600
+
+while :; do
+	case "$1" in
+		-h) echo "Usage $0: [-h] [-w warning (default: $warning)] [-c critical (default: $critical)]"
+		    shift;
+		    exit 2;
+		    ;;
+		-w) warning=$2
+		    shift; shift;
+		    ;;
+		-c) critical=$2
+		    shift; shift;
+		    ;;
+		--)
+		    shift; break;
+		    ;;
+	esac
+done
+
+delay=`/usr/local/bin/psql -U postgres --pset expanded=yes -c "select now() - pg_last_xact_replay_timestamp() AS replication_delay;" | tail -2 | head -1 | cut -d '|' -f 2 | cut -d ' ' -f 2 | cut -d '.' -f 1 | awk -F: '{ print ($1 * 3600) + ($2 * 60) + $3 }'`
+
+if [ $delay -gt $critical ]
+then
+  echo "CRITICAL: $delay seconds behind master"
+  exit 2
+elif [ $delay -gt $warning ]
+then
+  echo "WARNING: $delay seconds behind master"
+  exit 1
+else
+  echo "OK: $delay seconds behind master"
+  exit 0
+fi