unicorn_init.sh

#!/bin/sh

### BEGIN INIT INFO
# Provides:          unicorn
# Required-Start:    $all
# Required-Stop:     $network $remote_fs $local_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Starts the unicorn app server
# Description:       Starts unicorn using start-stop-daemon
### END INIT INFO

# https://unicorn.bogomips.org/SIGNALS.html
# http://unicorn.bogomips.org/examples/init.sh

# If a command fails, set -e will make the whole script exit,
# instead of just resuming on the next line.
set -e

# Treat unset variables as an error, and immediately exit.
# Exit your script if you try to use an uninitialised variable
set -u

# Feel free to change any of the following variables for your app:
APP_NAME=appname
AS_USER=deployer

HOME_PATH=/home/$AS_USER
APP_ROOT=$HOME_PATH/apps/$APP_NAME
CURRENT_APP_ROOT=$APP_ROOT/current
INIT_CONF=$HOME_PATH/.unicorn/$APP_NAME/config.rb

TIMEOUT=${TIMEOUT-60}

# make sure the app exists
cd $CURRENT_APP_ROOT || exit 1

CMD="cd $CURRENT_APP_ROOT && bundle exec unicorn -D -c $INIT_CONF -E production"

PID=$APP_ROOT/shared/pids/unicorn.pid
OLD_PIN="$PID.oldbin"

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

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

case "$1" in
start)
  sig 0 && echo >&2 "Already running" && exit 0
  echo "Starting"
  su - $AS_USER -c "$CMD"
  ;;
stop)
  echo "Stopping"
  sig QUIT && exit 0
  echo >&2 "Not running"
  ;;
force-stop)
  echo "Force stopping"
  sig TERM && exit 0
  echo >&2 "Not running"
  ;;
restart|reload)
  sig HUP && echo reloaded OK && exit 0
  echo >&2 "Couldn't reload, starting '$CMD' instead"
  su - $AS_USER -c "$CMD"
  ;;
upgrade)
  if sig USR2 && sleep 2 && sig 0 && oldsig QUIT
  then
    n=$TIMEOUT
    while test -s $OLD_PIN && test $n -ge 0
    do
      printf '.' && sleep 1 && n=$(( $n - 1 ))
    done
    echo

    if test $n -lt 0 && test -s $OLD_PIN
    then
      echo >&2 "$OLD_PIN still exists after $TIMEOUT seconds"
      exit 1
    fi
    exit 0
  fi
  echo >&2 "Couldn't upgrade, starting '$CMD' instead"
  $CMD
  ;;
reopen-logs)
  sig USR1 && echo rotated logs OK && exit 0
  echo >&2 "Couldn't rotate logs" && exit 1
  ;;
*)
  echo >&2 "Usage: $0 <start|stop|restart|upgrade|force-stop|reopen-logs>"
  exit 1
  ;;
esac