Unicorn Upgrade Scripts

unicorn_init.erb

#!/bin/sh
### BEGIN INIT INFO
# Provides:          unicorn
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Manage unicorn server
# Description:       Start, stop, restart unicorn server for a specific application.
### END INIT INFO

set -e #if a command ends with non-zero status, exit
set -u #if a variable isn't set, exit

# Feel free to change any of the following variables for your app:
TIMEOUT=${TIMEOUT-60}
APP_ROOT=<%= current_path %>
PID=<%= unicorn_pid %>
CMD="cd <%= current_path %>; bundle exec unicorn -D -c <%= unicorn_config %> -E <%= rails_env %>"
AS_USER=<%= unicorn_user %>


#When sent a USR2, Unicorn will suffix its pidfile with .oldbin and
  # immediately start loading up a new version of itself (loaded with a new
  # version of our app). When this new Unicorn is completely loaded
  # it will begin spawning workers. The first worker spawned will check to
  # see if an .oldbin pidfile exists. If so, this means we've just booted up
  # a new Unicorn and need to tell the old one that it can now die. To do so
  # we send it a QUIT.
OLD_PID="$PID.oldbin"

cd $APP_ROOT || exit 1

sig () {
  test -s "$PID" && kill -$1 `cat $PID`
}

oldsig () {
  test -s $OLD_PID && kill -$1 `cat $OLD_PID`
}

run () {
  if [ "$(id -un)" = "$AS_USER" ]; then
    eval $1
  else
    su -c "$1" - $AS_USER
  fi
}

workersig () {
  workerpid="<%= current_path %>/tmp/pids/unicorn.worker.$2.pid"
  test -s "$workerpid" && kill -$1 `cat $workerpid`
}

case "$1" in
start)
  sig 0 && echo >&2 "Start failed: Unicorn already running! Exiting!" && exit 0
  echo "Starting: "
  run "$CMD"
  ;;
stop)
  sig QUIT && exit 0
  echo >&2 "Stop failed: Unicorn isn't running."
  ;;
force-stop)
  sig TERM && exit 0
  echo >&2 "Force-stop failed: Unicorn isn't running"
  ;;
restart|reload)
  sig HUP && echo reloaded OK && exit 0
  echo >&2 "Reload failed: executing '$CMD' "
  run "$CMD"
  ;;
upgrade)
  if test -s $PID; then ORIG_PID=`cat $PID`; else ORIG_PID=0; fi

  echo 'Original PID: ' $ORIG_PID

  if sig USR2
  then
    echo 'USR2 sent; Waiting for .oldbin'
    n=$TIMEOUT
    
    #wait for .oldpid to be written
    while (!(test -s $OLD_PID) && test $n -ge 0)
    do
      printf '.' && sleep 1 && n=$(( $n - 1 ))    
    done
    
    echo 'Waiting for new pid file'
    #when this loop finishes, should have new pid file
    while (!(test -s $PID ) || test -s $OLD_PID) && test $n -ge 0
    do
      printf '.' && sleep 1 && n=$(( $n - 1 ))
    done

    if test -s $PID
    then 
      NEW_PID=`cat $PID`
    else 
      echo 'New master failed to start; see error log'
      exit 1
    fi
    
    #timeout has elapsed, verify new pid file exists
    if [ $ORIG_PID -eq $NEW_PID ]
    then
      echo
      echo >&2 'New master failed to start; see error log'
      exit 1
    fi

    echo 'New PID: ' $NEW_PID

    #verify old master QUIT
		echo
    if test -s $OLD_PID
    then
      echo >&2 "$OLD_PID still exists after $TIMEOUT seconds"
      exit 1
    fi
    
    printf 'Unicorn successfully upgraded'
    exit 0
  fi
  echo >&2 "Upgrade failed: executing '$CMD' "
  run "$CMD"
	;;
kill_worker)
  workersig QUIT $2 && exit 0
  echo >&2 "Kill Worker failed: worker not running"
  ;;
reopen-logs)
  sig USR1
  ;;
*)
  echo >&2 "Usage: $0 <start|stop|restart|upgrade|force-stop|reopen-logs>"
  exit 1
  ;;
esac

unicorn_init_upgrade_task.sh

upgrade)
  if test -s $PID; then ORIG_PID=`cat $PID`; else ORIG_PID=0; fi

  echo 'Original PID: ' $ORIG_PID

  if sig USR2
  then
    echo 'USR2 sent; Waiting for .oldbin'
    n=$TIMEOUT
    
    #wait for .oldpid to be written
    while (!(test -s $OLD_PID) && test $n -ge 0)
    do
      printf '.' && sleep 1 && n=$(( $n - 1 ))    
    done
    
    echo 'Waiting for new pid file'
    #when this loop finishes, should have new pid file
    while (!(test -s $PID ) || test -s $OLD_PID) && test $n -ge 0
    do
      printf '.' && sleep 1 && n=$(( $n - 1 ))
    done

    if test -s $PID
    then 
      NEW_PID=`cat $PID`
    else 
      echo 'New master failed to start; see error log'
      exit 1
    fi
    
    #timeout has elapsed, verify new pid file exists
    if [ $ORIG_PID -eq $NEW_PID ]
    then
      echo
      echo >&2 'New master failed to start; see error log'
      exit 1
    fi

    echo 'New PID: ' $NEW_PID

    #verify old master QUIT
		echo
    if test -s $OLD_PID
    then
      echo >&2 "$OLD_PID still exists after $TIMEOUT seconds"
      exit 1
    fi
    
    printf 'Unicorn successfully upgraded'
    exit 0
  fi
  echo >&2 "Upgrade failed: executing '$CMD' "
  run "$CMD"
	;;