Debian Unicorn Init Script

myapp.conf

## A sample /etc/unicorn/my_app.conf
##
APP_ENV=production
APP_ROOT=/home/myuser/legendsu
SHARED_ROOT=/home/myuser/shared
UNICORN="/home/myuser/.rvm/gems/ruby-2.1.2/bin/unicorn"

unicorn.sh

#!/usr/bin/env bash
### BEGIN INIT INFO
# Provides: unicorn
# Required-Start: $all
# Required-Stop: $network $local_fs $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start the unicorns at boot
# Description: Enable at boot time.
### END INIT INFO

# This is /etc/init.d/unicorn init.d script for single or multiple unicorn installations.
# Expects at least one .conf file in /etc/unicorn/
# chmod 755 /etc/init.d/unicorn
# update-rc.d unicorn defaults
#
# If you call this script without any config parameters, it will attempt to run the
# init command for all your unicorn configurations listed in /etc/unicorn/*.conf
#
# service unicorn restart # starts all unicorns
#
# If you specify a particular config, it will only operate on that one
#
# service unicorn restart my_app

__sig()
{
  typeset __pid
  [[ -s "$2" ]]       &&
  __pid="$(cat "$2")" &&
  [[ -n "${__pid}" ]] &&
  kill -$1 "${__pid}" >/dev/null 2>&1 ||
  return $?
}

sig()
{
  __sig "$1" "$PID" || return $?
}

oldsig()
{
  __sig "$1" "$OLD_PID" || return $?
}

run()
{
  echo -n "$1 - "
  shift
  if
    "$@"
  then
    echo "OK"
  else
    typeset result=$?
    echo "Failed!" >&2
    return $result
  fi
}

prefix_command_with_su_fix_quoting()
{
  typeset -a __temp
  __temp=()
  while
    (( $# ))
  do
    __temp+=( "'$1'" )
    shift
  done
  CMD=( su - "${__owner}" -c "cd '$APP_ROOT' && ${__temp[*]}" )
}

setup ()
{
  echo "$APP_ROOT: "
  cd $APP_ROOT || return $?

  export PID=$SHARED_ROOT/tmp/pids/unicorn.pid
  export OLD_PID="$PID.oldbin"
  export APP_ENV=production

  CMD=( "$UNICORN" -E production -c "${SHARED_ROOT}/config/unicorn.rb" -D )

  typeset __owner="$(stat -c "%U" "${APP_ROOT}")"
  if
    [[ "${USER:=$(whoami)}" == "${__owner}" ]]
  then
    true # it's all fine we run as owner of the app
  elif
    (( UID == 0 ))
  then
    prefix_command_with_su_fix_quoting "${CMD[@]}"
  else
    echo "ERROR: running not as owner(${__owner}) of '$APP_ROOT' and not as root($USER), prefix with 'sudo' and try again!"
    return 2
  fi
}

cmd_start()
{
  if sig 0
  then echo "Already started"
  else run "Starting" "${CMD[@]}" || return $?
  fi
}

wait_pid_kill()
{
  typeset __count=$1
  while
    (( __count > 0 )) &&
    sig 0
  do
    : $(( __count-- ))
    sleep 1s
  done
  sig 0 || return $?
}

cmd_stop()
{
  run "Stopping" sig QUIT
  if
    wait_pid_kill 5
  then
    run "Force stop" sig TERM
    if wait_pid_kill 3
    then return 1
    fi
  fi
}

cmd_restart()
{
  cmd_stop && cmd_start || return $?
}

cmd_reload()
{
  run "Reloading" sig USR2 &&
  wait_pid_kill 5 &&
  oldsig QUIT ||
  oldsig TERM ||
  cmd_restart ||
  return $?
}

cmd_rotate()
{
  run "Rotate" sig USR1  ||
  cmd_start ||
  return $?
}

cmd()
{
  setup || return $?
  case "$1" in
    start|stop|restart|reload|rotate)
      cmd_$1 || return $?
      ;;
    upgrade)
      cmd_reload || return $?
      ;;
    *)
      echo "Usage: $0 <start|stop|restart|reload|upgrade|rotate>" >&2
      return 1
      ;;
  esac
}

# either run the start/stop/reload/etc command for every config under /etc/unicorn
# or just do it for a specific one
# $1 contains the start/stop/etc command
# $2 if it exists, should be the specific config we want to act on
start_stop ()
{
  if
    [[ -n "$2" ]]
  then
    . "/etc/unicorn/$2.conf" || return $?
    cmd "$1" || return $?
  else
    for CONFIG in /etc/unicorn/*.conf
    do
      . "$CONFIG" || return $?
      cmd "$1" || return $?
    done
   fi
}

start_stop "$@"