control script with restart protection

ctl.erb

#!/bin/bash

RUN_DIR=/var/vcap/sys/run/hello-go
LOG_DIR=/var/vcap/sys/log/hello-go
PIDFILE=${RUN_DIR}/pid

case $1 in

  start)
    mkdir -p $RUN_DIR $LOG_DIR
    chown -R vcap:vcap $RUN_DIR $LOG_DIR

    if [ -f $PIDFILE ]; then
      pid=`head -1 $PIDFILE`
      if ps awwx | grep "^${pid}[ ].*hello-go"; then
        echo "hello-go is already running with PID $pid"
        exit 0
      fi
    fi

    echo $$ > $PIDFILE

    cd /var/vcap/packages/hello-go

    exec /var/vcap/packages/hello-go/bin/hello-go \
      >>  $LOG_DIR/hello-go.stdout.log \
      2>> $LOG_DIR/hello-go.stderr.log

    ;;

  stop)

    kill -9 `cat $PIDFILE`

    rm -f $PIDFILE

    ;;

  *)
    echo "Usage: ctl {start|stop}" ;;

esac