#!/bin/bash
### BEGIN INIT INFO
# Provides:          datastax-agent
# Required-Start:    $network $local_fs $remote_fs $named $syslog $time
# Required-Stop:     $network $local_fs $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: DataStax Agent
### END INIT INFO

DESC="DataStax Agent"
NAME="datastax-agent"
USER="cassandra"
MONITOR_NAME="datastax-agent-monitor"

TAC="datastax-agent.*-standalone.jar"
PIDFILE="/var/run/datastax-agent/datastax-agent.pid"
MONITOR_PIDFILE="/var/run/datastax-agent/datastax-agent-monitor.pid"
LOG="/var/log/datastax-agent/agent.log"
STARTUP_LOG="/var/log/datastax-agent/startup.log"
OPSC_SSL_DIR="/var/lib/datastax-agent/ssl"
OPSC_ADDR_DIR="/var/lib/datastax-agent/conf"
INIT_VERBOSE=yes

SCRIPTNAME="$0"

# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Load the VERBOSE setting and other rcS variables
[ -r /lib/init/vars.sh ] && . /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

[ -d "/var/run/$NAME" ] || mkdir "/var/run/$NAME"
[ -d "/var/log/$NAME" ] || mkdir "/var/log/$NAME"
[ -f "$LOG" ] || touch "$LOG"
[ -f "$STARTUP_LOG" ] || touch "$STARTUP_LOG"
[ -e "$PIDFILE" ] || touch $PIDFILE

chown -RL $USER:$USER "/var/log/$NAME" "/var/run/$NAME"

is_running()
{
    if [ -f "$PIDFILE" ]; then
        PID=$(cat "$PIDFILE" 2>/dev/null)
        grep -q "$TAC" "/proc/$PID/cmdline" 2>/dev/null && return 0
        return 1
    fi
    return 3
}

do_start()
{
    # Return
    #   0 if daemon has been started
    #   1 if daemon was already running
    #   2 if daemon could not be started

    is_running && return 1

    nohup /usr/share/datastax-agent/bin/datastax_agent_monitor >> /var/log/datastax-agent/agent.log 2>&1 &
    sleep 1

    export OPSC_SSL_DIR OPSC_ADDR_DIR PID="$PIDFILE"
    nohup start-stop-daemon --start -c $USER --pidfile $PIDFILE --exec /usr/share/datastax-agent/bin/datastax-agent > $STARTUP_LOG 2>&1 &
    return 0
}

do_stop()
{
    # Return
    #   0 if daemon has been stopped
    #   1 if daemon was already stopped
    #   2 if daemon could not be stopped
    #   other if a failure occurred

    # stop the monitor process first
    # we don't use --exec /bin/bash because it doesn't seem to always work
    start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 \
        --pidfile "$MONITOR_PIDFILE"
    MONITOR_RETVAL=$?

    [ $MONITOR_RETVAL -eq 2 ] && return 2 # Couldn't stop
    [ $MONITOR_RETVAL -eq 3 ] && return 3 # Other error
    rm -f "$MONITOR_PIDFILE"

    is_running || return 1

    # then stop the agent
    start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 \
        --pidfile "$PIDFILE"

    RETVAL=$?
    [ $RETVAL -eq 2 ] && return 2 # Couldn't stop
    [ $RETVAL -eq 3 ] && return 3 # Other error
    rm -f "$PIDFILE"
    return "$RETVAL"
}

case "$1" in
  start)
    [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
    do_start
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
  ;;
  stop)
    [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
    do_stop
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  status)
    is_running
    stat=$?
    case "$stat" in
      0) log_daemon_msg "$DESC $NAME is running" ;;
      1) log_daemon_msg "could not access pidfile for $DESC $NAME" ;;
      *) log_daemon_msg "$DESC $NAME is not running" ;;
    esac
    exit "$stat"
    ;;
  #reload|force-reload)
    #
    # If do_reload() is not implemented then leave this commented out
    # and leave 'force-reload' as an alias for 'restart'.
    #
    #log_daemon_msg "Reloading $DESC" "$NAME"
    #do_reload
    #log_end_msg $?
    #;;
  restart|force-reload)
    #
    # If the "reload" option is implemented then remove the
    # 'force-reload' alias
    #
    log_daemon_msg "Restarting $DESC" "$NAME"
    do_stop
    case "$?" in
      0|1)
        do_start
        case "$?" in
            0) log_end_msg 0 ;;
            1) log_end_msg 1 ;; # Old process is still running
            *) log_end_msg 1 ;; # Failed to start
        esac
        ;;
      *)
        # Failed to stop
        log_end_msg 1
        ;;
    esac
    ;;
  *)
    echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
    exit 3
    ;;
esac

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