#!/bin/bash

# addtimestamp.sh
# (C) 2012 Daniel Marschall, ViaThinkSoft
#
# This script watches a logfile and adds timestamps in front of each line
# This is e.g. necessary for MySQL logs in combination with fail2ban, because MySQL does not log timestamps correctly in the general log ...
#
# Version: 2012-02-02 02:44

if [ $# -lt 2 ]
then
	echo "Syntax: $0 <infile> <outfile> [<filter regex>]";
	exit 2;
fi

ERRORLOG="$1"; shift;
OUTLOG="$1"; shift;
FILTERREGEX="$1"; shift;

(
	tail -n 1 -F "$ERRORLOG" | while read inputline
	do
		OUTPUT=0;
		if [ "$FILTERREGEX" = "" ]
		then
			OUTPUT=1;
		else
			echo "$inputline" | grep -e "$FILTERREGEX" 2>&1 > /dev/null;
			if [ $? -eq 0 ]
			then
				OUTPUT=1;
			else
				OUTPUT=0;
			fi
		fi

		if [ $OUTPUT -eq 1 ]
		then
			TIMESTAMP=$( date "+%Y-%m-%d %H:%M:%S %z" );
			echo "[$TIMESTAMP] $inputline";
		fi
	done
) 2>"/dev/null" >> "$OUTLOG";

exit 0;