--- /dev/null
+#!/bin/bash
+
+STATE_OK=0
+STATE_WARNING=1
+STATE_CRITICAL=2
+STATE_UNKNOWN=3
+
+user=$1
+host=$2
+port=$3
+
+lag=$(psql -h $host -p $port -A -t -c "SELECT COALESCE(EXTRACT(EPOCH FROM replay_lag),0) FROM pg_stat_replication WHERE usename='$user'" 2>/dev/null)
+exit_code=$?
+
+if [[ $exit_code -ne 0 ]]; then
+ echo "UNKNOWN - Impossible to run psql command"
+ exit $STATE_UNKNOWN
+elif [[ -z "$lag" ]]; then
+ echo "UNKNOWN - No replication found for $user"
+ exit $STATE_UNKNOWN
+else
+ output="Replication lag for $user is ${lag}s"
+ LC_ALL=C lag=$(printf "%.*f" 0 $lag)
+
+ if [[ $lag -lt 5 ]]; then
+ echo "OK - $output"
+ exit $STATE_OK
+ elif [[ $lag -lt 10 ]]; then
+ echo "WARNING - $output"
+ exit $STATE_WARNING
+ else
+ echo "CRITICAL - $output"
+ exit $STATE_CRITICAL
+ fi
+fi