Run rails application from upstart with start-stop-daemon

rails app upstart init script

description     "Rails Application"

start on runlevel [2345]
stop on runlevel [!2345]

console log
respawn
chdir /srv/apps/rails_path/current

env APP_NAME="rails-app"
env HOME="/srv/apps/rails_path/current"
env GEM_PATH="/var/lib/ruby-gems/rails-app/gems/1.9.1"
env PATH="/sbin:/usr/sbin:/bin:/usr/bin:/var/lib/ruby-gems/rails-app/gems/1.9.1/bin"
env BUNDLE_PATH="/var/lib/ruby-gems/rails-app/gems/1.9.1/bin/bundle"
env RAILS_ENV="production"
env RAILS_PORT="3000"

pre-start script
   start-stop-daemon --start -b -d ${HOME} -p ${HOME}/tmp/pids/thin.pid --exec ${BUNDLE_PATH} -m -- exec thin start -e ${RAILS_ENV} -p ${RAILS_PORT} -l $HOME/log/thin.log
   sudo initctl emit ${APP_NAME}_start
end script

post-stop script
  start-stop-daemon --stop -d ${HOME} -p ${HOME}/tmp/pids/thin.pid
  sudo initctl emit ${APP_NAME}_stop
end script

Just setup BUNDLE_PATH and GEM_PATH to proper values they can be loaded from rvm in script.

Why use start-stop-daemon? Upstart can handle it all for you (including properly respawning) if you don't daemonize or background Thin.