#!/bin/bash
#
### BEGIN INIT INFO
# Provides:          proxysql-binlogreader
# Required-Start:    $local_fs
# Required-Stop:     $local_fs
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: ProxySQL Binlog Reader for MySQL
### END INIT INFO

DAEMON=/usr/bin/proxysql_binlog_reader
DATADIR="/var/lib/proxysqlbinlogreader"
LISTENPORT="8888"
MYSQL_HOST="127.0.0.1"
MYSQL_PORT="3306"
MYSQL_USER="proxysql-binlogreader"
MYSQL_PASSWD="XXXXXXX"

# Include proxysql-binlogreader defaults if available
if [ -r /etc/default/proxysql-binlogreader ]; then
        . /etc/default/proxysql-binlogreader
fi

test -x $DAEMON || exit 0

. /lib/init/vars.sh
. /lib/lsb/init-functions

OPTS="-h $MYSQL_HOST -u $MYSQL_USER -p$MYSQL_PASSWD -P $MYSQL_PORT -l $LISTENPORT -L $DATADIR/proxysql_binlog_reader.log"
PIDFILE="/tmp/proxysql_mysqlbinlog.pid"
USER="proxysql-binlogreader"

getpid() {
        if [ -f $PIDFILE ]
        then
                if [ -r $PIDFILE ]
                then
                        pid=`cat $PIDFILE`
                        if [ "X$pid" != "X" ]
                        then
                                # Verify that a process with this pid is still running.
                                pid=`ps -p $pid | grep $pid | grep -v grep | awk '{print $1}' | tail -1`
                                if [ "X$pid" = "X" ]
                                then
                                        # This is a stale pid file.
                                        rm -f $PIDFILE
                                        echo "Removed stale pid file: $PIDFILE"
                                fi
                        fi
                else
                        echo "Cannot read $PIDFILE."
                        exit 1
                fi
        fi
}


testpid() {
        pid=`ps -p $pid | grep $pid | grep -v grep | awk '{print $1}' | tail -1`
        if [ "X$pid" = "X" ]
        then
                # Process is gone so remove the pid file.
                rm -f $PIDFILE
        fi
}

is_pid_child_of_docker() {
        # Check if docker is installed (no point in checking if docker isn't present)
        which docker &> /dev/null
        if [ "$?" -eq 1 ] ; then
                return 0;
        fi

        # Check if any docker containers are running (check required since empty output fails next command)
        if [ "$(docker ps -q | wc -l)" -eq 0 ] ; then
                return 0;
        fi

        IFS=$'\n'
        docker_pids=($(docker ps -q | xargs docker inspect --format '{{.State.Pid}}'))
        local child_pid=$1

        for i in "${docker_pids[@]}"
        do
                if [ "$i" -eq "$child_pid" ] ; then
                        return 1;
                fi
        done

        return 0
}

safe_kill() {
        local pid=$1
        local param=$2

        parent_pid=`ps -f $pid | grep [p]roxysql_binlog_reader |  awk '{print $3}'`
        if [ -n "$parent_pid" ]; then
                is_pid_child_of_docker $parent_pid
                is_child=$?
                if [[ $is_child -eq 0 ]]; then
                        kill $param $pid
                fi
        else ##the process has not parent, I can kill it
                kill $param $pid
        fi
}

start() {
        echo -n "Starting ProxySQL Binlog Reader: "
        getpid
        if [ "X$pid" = "X" ]
        then
                su - $USER -s /bin/bash -c "proxysql_binlog_reader $OPTS"
                if [ "$?" = "0" ]; then
                        echo "DONE!"
                        return 0
                else
                        echo "FAILED!"
                        return 1
                fi
        else
                echo "ProxySQL Binlog Reader is already running."
                exit 0
        fi
}

stop() {
        echo -n "Shutting down ProxySQL Binlog Reader: "
        getpid
        if [ "X$pid" = "X" ]
        then
                echo "ProxySQL Binlog Reader was not running."
                exit 0
        else
                # Note: we send a kill to all the processes, not just to the child
                for i in $(ps -eo pid,cmd | grep [p]roxysql_binlog_reader | grep "$LISTENPORT" | awk -F' ' '{print $1}') ; do
                        if [ "$i" != "$$" ]; then
                                safe_kill $i
                        fi
                done
                #  Loop until it does.
                savepid=$pid
                CNT=0
                TOTCNT=0
                while [ "X$pid" != "X" ]
                do
                        # Loop for up to 20 second
                        if [ "$TOTCNT" -lt "200" ]
                        then
                                if [ "$CNT" -lt "10" ]
                                then
                                        CNT=`expr $CNT + 1`
                                else
                                        echo -n "."
                                        CNT=0
                                fi
                                TOTCNT=`expr $TOTCNT + 1`

                                sleep 0.1

                                testpid
                        else
                                pid=
                        fi
                done
                pid=$savepid
                testpid
                if [ "X$pid" != "X" ]
                then
                        echo
                        echo "Timed out waiting for ProxySQL Binlog Reader to exit."
                        echo "  Attempting a forced exit..."
                        for i in $(ps -eo pid,cmd | grep [p]roxysql_binlog_reader | grep "$LISTENPORT" | awk -F' ' '{print $1}') ; do
                                if [ "$i" != "$$" ]; then
                                        safe_kill $i '-9'
                                fi
                        done
                fi

                pid=$savepid
                testpid
                if [ "X$pid" != "X" ]
                then
                        echo "Failed to stop ProxySQL Binlog Reader"
                        exit 1
                else
                        echo "DONE!"
                fi
        fi
}


status() {
        getpid
        if [ "X$pid" = "X" ]
        then
                echo "ProxySQL Binlog Reader is not running."
                exit 1
        else
                echo "ProxySQL Binlog Reader is running ($pid)."
                exit 0
        fi
}

case "$1" in
        start)
                start
        ;;
        stop)
                stop
        ;;
        status)
                status
        ;;
        restart)
                stop
                start
        ;;
        *)
                echo "Usage: ProxySQL Binlog Reader {start|stop|status|restart}"
                exit 1
        ;;
esac
exit $?