#!/bin/bash

#############################################################
#### Fail2Ban Metrics install Script for Prometheus      #### 
#### Centos/Redhat and Debian/Ubuntu Servers.            ####       
####                                                     ####
#### Author: Phil Connor 08/27/2023                      ####
#### Contact: contact@mylinux.work                       ####
#### Version 1.92.011924                                 ####
####                                                     ####
#### To use this script chmod it to 755                  ####
#### or simply type bash <filename.sh>                   ####  
#############################################################




if ! crontab -l | grep -q "fail2ban_metrics.sh"; then
    echo -e "$(crontab -u root -l)\n*/5 * * * * /usr/local/bin/fail2ban_metrics.sh > /var/lib/node_exporter/fail2ban_metrics.prom 2>&1" | crontab -u root -
fi

install_fail2_metrics() {
	{
		{
			echo 'jails=0'
			echo ''
			# shellcheck disable=SC2016,SC2028
			echo 'for jail in $(fail2ban-client status | grep '\''Jail list:'\'' | sed '\''s/.*Jail list:[\t ]*//;s/,//g'\'')' 
			echo '	do'
			# shellcheck disable=SC2004,SC2016,SC2030
			echo '		jails=$(($jails + 1))'
			# shellcheck disable=SC2016
			echo '		fail2ban-client status "$jail" | awk -F: '\'' '
			# shellcheck disable=SC2016
			echo '		$1 ~ /Currently failed/ {'
			# shellcheck disable=SC2016,SC2154
			echo '			print "fail2ban_failed_current{jail=\"'\''"$jail"'\''\"} " $2;'
			echo '		}'
			# shellcheck disable=SC2016
			echo '		$1 ~ /Total failed/ {'
			# shellcheck disable=SC2016
			echo '			print "fail2ban_failed_total{jail=\"'\''"$jail"'\''\"} " $2;'
			echo '		}'
			# shellcheck disable=SC2016
			echo '		$1 ~ /Currently banned/ {'
			# shellcheck disable=SC2016
			echo '			print "fail2ban_banned_current{jail=\"'\''"$jail"'\''\"} " $2;'
			echo '		}'
			# shellcheck disable=SC2016
			echo '		$1 ~ /Total banned/ {'
			# shellcheck disable=SC2016
			echo '			print "fail2ban_banned_total{jail=\"'\''"$jail"'\''\"} " $2;'
			echo '		}'\'' '
			echo '  done | sort | awk '\'' '
			echo ''
			echo 'BEGIN {failc=1; failt=1; banc=1; bant=1}'
			echo '/^fail2ban_failed_current/ { if (failc) {'
			echo '	print "# HELP fail2ban_failed_current Current number of failures.";'
			echo '	print "# TYPE fail2ban_failed_current gauge";'
			echo '	failc=0;'
			echo '	} }'
			echo '/^fail2ban_failed_total/ { if (failt) {'
			echo '	print "# HELP fail2ban_failed_total Total number of failures.";'
			echo '	print "# TYPE fail2ban_failed_total counter";'
			echo '	failt=0;'
			echo '	} }'
			echo '/^fail2ban_banned_current/ { if (banc) {'
			echo '	print "# HELP fail2ban_banned_current Current number banned.";'
			echo '	print "# TYPE fail2ban_banned_current gauge";'
			echo '	banc=0;'
			echo '	} }'
			echo '/^fail2ban_banned_total/ { if (bant) {'
			echo '	print "# HELP fail2ban_banned_total Total number banned.";'
			echo '	print "# TYPE fail2ban_banned_total counter";'
			echo '	bant=0;'
			echo '	} }'
			# shellcheck disable=SC2016
			echo '{ print $0 }'\'' '
			echo ''
			echo 'cat <<EOF'
			echo '# HELP fail2ban_jails Total number of jails.'
			echo '# TYPE fail2ban_jails gauge'
			# shellcheck disable=SC2016
			echo 'fail2ban_jails $jails'
			echo 'EOF'
			}  > /usr/local/bin/fail2ban_metrics.sh

		chmod 755 /usr/local/bin/fail2ban_metrics.sh
	}
}

install_fail2_metrics