#!/bin/bash
# Author: Giovanni Mancini
# Date 24/05/2017
# Content: scan dovecot logs for proxy remote errors

[[ -z $1 ]] && DEFAULT_BACKTIME=10 || DEFAULT_BACKTIME=$1

[[ -z $2 ]] && NRERR_THRESHOLD=10 || NRERR_THRESHOLD=$2

ACTUAL_LOG=$(echo /var/log/dovecot_$(date +%Y%m%d).$(date +%H).log)

PREVIOUS_LOG=$(echo /var/log/dovecot_$(date -d "$DEFAULT_BACKTIME minutes ago" +%Y%m%d).$(date -d "$DEFAULT_BACKTIME minutes ago" +%H).log)

TMPFILE="/tmp/proxy_errors.tmp"

>"${TMPFILE}"

if [ "$ACTUAL_LOG" != "$PREVIOUS_LOG" ]
then
        sudo /usr/bin/tail -n 500000 $PREVIOUS_LOG | awk -vSTART="$(date -d "$DEFAULT_BACKTIME minutes ago" '+%T')" ' $3 > START { print $0 }' | grep -i 'imap-login: Error: proxy: Remote' | awk '{ print $10 }' | sort | uniq -c >> "${TMPFILE}"
        sudo /usr/bin/tail -n 500000 $ACTUAL_LOG | awk -vSTART="$(date -d "$DEFAULT_BACKTIME minutes ago" '+%T')" ' $3 > START { print $0 }' | grep -i 'imap-login: Error: proxy: Remote' | awk '{ print $10 }' | sort | uniq -c >> "${TMPFILE}"
else
        sudo /usr/bin/tail -n 500000 $ACTUAL_LOG | awk -vSTART="$(date -d "$DEFAULT_BACKTIME minutes ago" '+%T')" ' $3 > START { print $0 }' | grep -i 'imap-login: Error: proxy: Remote' | awk '{ print $10 }' | sort | uniq -c >> "${TMPFILE}"
fi


ERR_HOSTS=$(awk -v NRERR="$NRERR_THRESHOLD" '$1>NRERR { gsub(/:.*/,"",$2) ; print $2"["$1" errors]"}' "${TMPFILE}" | xargs)
TOTERROR=$(awk '{ sum+=$1 } END { print sum }' "${TMPFILE}")

if [ -z "$ERR_HOSTS" ]
then
        echo "OK: no proxy errors on backends | proxy_tot_err=${TOTERROR}" && exit 0
else
        echo "CRITICAL: proxy remote error for $ERR_HOSTS | proxy_tot_err=${TOTERROR}" | xargs && exit 2
fi