#!/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 - $output | time=${lag}s;5;10;0;"
    exit $STATE_OK
  elif [[ $lag -lt 10 ]]; then
    echo "WARNING - $output | time=${lag}s;5;10;0;"
    exit $STATE_WARNING
  else
    echo "CRITICAL - $output | time=${lag}s;5;10;0;"
    exit $STATE_CRITICAL
  fi
fi