Unicorn configuration

init_unicorn.sh

#!/bin/bash

set -e

### 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 (without .sh)
# init.d script for single or multiple unicorn installations. Expects at least one .conf 
# file in /etc/unicorn
#
# Modified by http://github.com/jlecour
# based on modified version by http://github.com/zewelor
# which based on modified version by http://github.com/killercup
# which based on modified version by jay@gooby.org http://github.com/jaygooby
# which is based on http://gist.github.com/308216 by http://github.com/mguterl
#
## A sample /etc/unicorn/my_app.conf
## 
## APP_NAME=my_app
## RAILS_ENV=staging
## RAILS_ROOT="/home/my_user/apps/${RAILS_ENV}/${APP_NAME}/current"
## UNICORN="${RAILS_ROOT}/bin/unicorn"
## APP_USER=my_user

# This configures a unicorn master for your app at /var/apps/www/my_app/current running in
# production mode. It will read config/unicorn.rb for further set up. 
#
# You should ensure different ports or sockets are set in each config/unicorn.rb if
# you are running more than one master concurrently.
#
# 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
#
# /etc/init.d/unicorn start # starts all unicorns
#
# If you specify a particular config, it will only operate on that one
#
# /etc/init.d/unicorn start my_app

DEFAULT_USER=my_user

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

cmd () {

  case $1 in
    start)
      sig 0 && echo >&2 "Already running" && return 0
      eval $CMD
      echo "Starting"
      ;;
    stop)
      sig QUIT && echo "Stopping" && return 0
      echo >&2 "Not running"
      ;;
    force-stop)
      sig TERM && echo "Forcing a stop" && return 0
      echo >&2 "Not running"
      ;;
    restart|reload|upgrade)
      sig USR2 && echo Upgraded && return 0
      echo >&2 "Couldn't upgrade, starting '$CMD' instead"
      eval $CMD
      ;;
    rotate)
      sig USR1 && echo rotated logs OK && return 0
      echo >&2 "Couldn't rotate logs" && return 1
      ;;
    *)
      echo >&2 "Usage: $0 <start|stop|restart|upgrade|rotate|force-stop>"
      exit 1
      ;;
    esac
}

setup () {
    CONFIG=$1

    if [ -z $APP_NAME ]; then
        echo "App name is not defined in ${CONFIG}"
        return 1
    fi
    if [ -z $APP_USER ]; then
        echo "App name is not defined in ${CONFIG}"
        return 1
    fi
    if [ -z $RAILS_ROOT ]; then
        echo "Rails root is not defined in ${CONFIG}"
        return 1
    fi
    if [ -z $RAILS_ENV ]; then
        echo "Rails environment is not defined in ${CONFIG}"
        return 1
    fi
    # If unicorn binary was not defined in config
    if [ -z $UNICORN ]; then
      UNICORN="${RAILS_ROOT}/bin/unicorn"
    fi

    echo "Launching ${APP_NAME} (${RAILS_ROOT})"

    cd $RAILS_ROOT || return 1
    export PID=$RAILS_ROOT/tmp/pids/unicorn.pid

    # SUDOCMD="rvmsudo -u ${APP_USER}"
    SUDOCMD="sudo -u ${APP_USER}"

    CMD="${SUDOCMD} RAILS_ENV=${RAILS_ENV} ${UNICORN} -E ${RAILS_ENV} -c ${RAILS_ROOT}/config/unicorn.rb -D"
    return 0
}

# 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

if [ $2 ]; then
  . /etc/unicorn/$2.conf
  setup "/etc/unicorn/$2.conf"
  if [ $? -eq 1 ]; then
    exit
  fi
  cmd $1
else
  for CONFIG in /etc/unicorn/*.conf; do
    # clean variables from prev configs
    unset APP_NAME
    unset APP_USER
    unset RAILS_ROOT
    unset RAILS_ENV
    unset UNICORN

    # import the variables
    . $CONFIG
    setup $CONFIG
    if [ $? -eq 1 ]; then
      continue
    fi
    # run the start/stop/etc command
    cmd $1
  done
fi

unicorn.rb

# This config script is heavily inspired by GitHub
# https://github.com/blog/517-unicorn

app_directory = "/home/my_user/apps/staging/my_app/current"

worker_processes 4

working_directory app_directory

listen "unix:#{app_directory}/tmp/pids/unicorn.sock", :backlog => 1024
# listen 3000

timeout 60

user 'hh', 'hh'

File.umask(027)

preload_app true

pid "#{app_directory}/tmp/pids/unicorn.pid"

stderr_path "#{app_directory}/log/unicorn.stderr.log"
stdout_path "#{app_directory}/log/unicorn.stdout.log"

if GC.respond_to?(:copy_on_write_friendly=)
  GC.copy_on_write_friendly = true
end

before_fork do |server, worker|
  ##
  # 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.
  #
  # Using this method we get 0 downtime deploys.

  old_pid = "#{server.config[:pid]}.oldbin"
  if File.exists?(old_pid) && server.pid != old_pid
    begin
      Process.kill("QUIT", File.read(old_pid).to_i)
    rescue Errno::ENOENT, Errno::ESRCH
      # someone else did our job for us
    end
  end
  # the following is recomended for Rails + "preload_app true"
  # as there's no need for the master process to hold a connection
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.connection.disconnect!
  end
end

after_fork do |server, worker|
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection
  end
end