keepalived-redis.sh

#!/bin/sh
set -x

REDIS_CLI="redis-cli"
REDIS_SERVER="/usr/bin/redis-server"
START_STOP="/sbin/start-stop-daemon"

E_INVALID_ARGS=65
E_INVALID_COMMAND=66
E_NO_SLAVES=67
E_DB_PROBLEM=68
E_BAD_CONFIG=69

SYSLOG_TAG="keepalived-redis"
SYSLOG_PRI="user.notice"

error() {
  echo "Exiting: ERROR $1: $2"
  exit $1
}

get_pidfile() {
	config_file=$1
	local pidfile=`grep -E "^\s*pidfile " $config_file | cut -d' ' -f2`
	echo $pidfile
}

get_port() {
	config_file=$1
	local port=`grep -E "^\s*port " $config_file | cut -d' ' -f2`
	echo $port
}

output() {
    echo $@
    echo $@ | logger -t $SYSLOG_TAG -p $SYSLOG_PRI
}

# start_redis $config
start_redis() {
	config_file=$1
	port=`get_port $config_file`
	alive=`$REDIS_CLI -p $port INFO`
	if [ $? -ne 0 ]; then
	    $START_STOP --start --quiet --umask 007 --pidfile `get_pidfile ${config_file}` --chuid redis:redis --exec $REDIS_SERVER -- $config_file
		sleep 1
	fi
}

start_master() {
	config_file=$1
	port=`get_port $config_file`
	$REDIS_CLI -p $port SLAVEOF no one
}

start_slave() {
	config_file=$1
	master_ip=$2
	master_port=$3
	port=`get_port $config_file`
	$REDIS_CLI -p $port SLAVEOF $master_ip $master_port
}

check_health() {
	config_file=$1
	port=`get_port $config_file`
	alive=`$REDIS_CLI -p $port INFO`
	if [ $? -ne 0 ]; then
    	local result=1
	else
    	local result=0
	fi
	echo $result
}

usage() {
	echo "Start Redis and promote to MASTER/SLAVE"
	echo "\nOptions: "
	echo "\t--master -c=REDIS_CONFIG             promote the redis-server to MASTER using the supplied redis.conf at REDIS_CONFIG"
	echo "\t--slave  -c=REDIS_CONFIG -h=IP:PORT  promote the redis-server to SLAVE of IP:PORT using the supplied redis.conf at REDIS_CONFIG"
	echo "\t--health -c=REDIS_CONFIG             check the health of the redis-server process configured for REDIS_CONFIG"
	echo "\t--fault  -c=REDIS_CONFIG             put the redis at REDIS_CONFIG in to a fault state"
	echo ""
	exit $E_INVALID_ARGS
}

for arg in "$@"; do
	case $arg in
	--master) arg_m=true;;
	--slave) arg_s=true;;
	--fault) arg_k=true;;
	--health) arg_h=true;;
	--config=*) arg_config=${arg#*=};;
	--host=*) arg_host=${arg#*=};;
	*) usage;;
	esac
done

if [ $arg_m ]; then
	if [ "$arg_config" == "" ] || [ ! -f $arg_config ]; then
		echo "Must pass --config with the path to a redis configuration file"
		exit $E_INVALID_ARGS
	fi

	if [ "`get_port $arg_config`" == "" ]; then
		error $E_BAD_CONFIG "Could not find redis port in ${arg_config}"
	fi

    output "Promoting redis-server to MASTER using ${arg_config}\n"
    start_redis $arg_config
    wait
    start_master $arg_config
elif [ $arg_h ]; then
	if [ "$arg_config" == "" ] || [ ! -f $arg_config ]; then
		echo "Must pass --config with the path to a redis configuration file"
		exit $E_INVALID_ARGS
	fi

	if [ "`get_port $arg_config`" == "" ]; then
		error $E_BAD_CONFIG "Could not find redis port in ${arg_config}"
	fi

    output "Checking health of redis using ${arg_config}\n"
    result=`check_health $arg_config`
    if [ $result -eq 0 ]; then
        output "Redis with ${arg_config} is running"
        exit 0
    else
        output "Redis with ${arg_config} is not running"
        exit 1
    fi
elif [ $arg_f ]; then
	if [ "$arg_config" == "" ] || [ ! -f $arg_config ]; then
		echo "Must pass --config with the path to a redis configuration file"
		exit $E_INVALID_ARGS
	fi

	if [ "`get_port $arg_config`" == "" ]; then
		error $E_BAD_CONFIG "Could not find redis port in ${arg_config}"
	fi

    output "Putting redis-server using ${arg_config} in to FAULT state"
elif [ $arg_s ]; then
	if [ "$arg_config" == "" ] || [ ! -f $arg_config ]; then
		echo "Must pass --config with the path to a redis configuration file"
		exit $E_INVALID_ARGS
	fi

	if [ "`get_port $arg_config`" == "" ]; then
		error $E_BAD_CONFIG "Could not find redis port in ${arg_config}"
	fi

    master_ip=`echo $arg_host | cut -d: -f1`
    master_port=`echo $arg_host | cut -d: -f2`
    if [ "$master_ip" == "" ] || [ "$master_port" == "" ]; then
        echo "Must pass --host as IP:PORT combination of redis master"
        exit $E_INVALID_ARGS
    fi
    output "Promoting redis-server to SLAVE of ${arg_host} using ${arg_config}"
    start_redis $arg_config
    wait
    start_slave $arg_config $master_ip $master_port
else
    usage
fi