README.md

You have your Rails Apps with specific Gemsets in RVM.

The following commands creates a wrapped unicorn_rails bin. Be sure to replace the variables and that you have unicorn in your bundle.

> rvmsudo rvm wrapper [RUBY VERSION]@[GEMSET] [GEMSET] unicorn_rails

Now you have a /usr/local/rvm/bin/[GEMSET]_unicorn_rails I will refer to [GEMSET]_unicorn_rails as [WRAPPED_NAME]

Create the other files now, especially /etc/init.d/unicorn_init:

> sudo update-rc.d unicorn_init defaults

_etc_unicorn_APPNAME.conf

# This is the actual config for your app
# Save this to /etc/unicorn/<APPNAME>.conf
# My configs look like this:

RAILS_ROOT=/home/deployer/<APPNAME>/current/
RAILS_ENV=production
UNICORN=/usr/local/rvm/bin/<WRAPPED_NAME>

unicorn.rb

# config/unicorn.rb
# Set environment to development unless something else is specified

DEFAULT_ENV = 'production'
PORT = 3000

USER_NAME = 'deployer'
USER_GROUP = 'developers'

APP_NAME = 'my_site'
APP_DIR = '/home/#{ USER_NAME }/#{ APP_NAME }'

env = ENV["RAILS_ENV"] || DEFAULT_ENV

# See http://unicorn.bogomips.org/Unicorn/Configurator.html for complete
# documentation.
worker_processes 4

# listen on both a Unix domain socket and a TCP port,
# we use a shorter backlog for quicker failover when busy
listen PORT # or "/tmp/#{ APP_NAME }.socket", :backlog => 64

# Preload our app for more speed
preload_app true

# nuke workers after 30 seconds instead of 60 seconds (the default)
timeout 30

pid "/tmp/unicorn.#{ APP_NAME }.pid"

# Production specific settings
if env == "production"
  # Help ensure your application will always spawn in the symlinked
  # "current" directory that Capistrano sets up.
  working_directory APP_DIR

  # feel free to point this anywhere accessible on the filesystem
  user USER_NAME, USER_GROUP
end

before_fork do |server, worker|
  # the following is highly 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

  # Before forking, kill the master process that belongs to the .oldbin PID.
  # This enables 0 downtime deploys.
  old_pid = "/tmp/unicorn.#{ APP_NAME }.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
end

after_fork do |server, worker|
  # the following is *required* for Rails + "preload_app true",
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection
  end

  # if preload_app is true, then you may also want to check and
  # restart any other shared sockets/descriptors such as Memcached,
  # and Redis.  TokyoCabinet file handles are safe to reuse
  # between any number of forked children (assuming your kernel
  # correctly implements pread()/pwrite() system calls)
end

unicorn_init.sh

#!/bin/sh
### 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/killercup
# 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
## 
## RAILS_ENV=production
## RAILS_ROOT=/var/apps/www/my_app/current
## UNICORN="/usr/local/rvm/bin/<WRAPPED_NAME>" #see rvm wrapper above
#
# 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

set -e
set -u

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

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

cmd () {

  case $1 in
    start)
      sig 0 && echo >&2 "Already running" && exit 0
      $CMD
      echo "Starting"
      ;;
    stop)
      sig QUIT && echo "Stopping" && exit 0
      echo >&2 "Not running"
      ;;
    force-stop)
      sig TERM && echo "Forcing a stop" && exit 0
      echo >&2 "Not running"
      ;;
    restart|reload)
      sig USR2 && sleep 5 && oldsig QUIT && echo "Killing old master" `cat $OLD_PID` && exit 0
      echo >&2 "Couldn't reload, starting '$CMD' instead"
      $CMD
      ;;
    upgrade)
      sig USR2 && echo Upgraded && exit 0
      echo >&2 "Couldn't upgrade, starting '$CMD' instead"
      $CMD
      ;;
    rotate)
            sig USR1 && echo rotated logs OK && exit 0
            echo >&2 "Couldn't rotate logs" && exit 1
            ;;
    *)
      echo >&2 "Usage: $0 <start|stop|restart|upgrade|rotate|force-stop>"
      exit 1
      ;;
    esac
}

setup () {

  echo "$RAILS_ROOT: "
  cd $RAILS_ROOT || exit 1
  export PID=$RAILS_ROOT/tmp/pids/unicorn.pid
  export OLD_PID="$PID.oldbin"
  export RAILS_ENV=production

  CMD="$UNICORN -c ${RAILS_ROOT}config/unicorn.rb -D"
}

start_stop () {

  # 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
    cmd $1
  else
    for CONFIG in /etc/unicorn/*.conf; do
      # import the variables
      . $CONFIG
      setup

      # run the start/stop/etc command
      cmd $1
    done
   fi
}

ARGS="$1 $2"
start_stop $ARGS