Unicorn / Monit setup

unicorn

#!/bin/sh
set -e
# Example init script, this can be used with nginx, too,
# since nginx and unicorn accept the same signals

# Feel free to change any of the following variables for your app:
TIMEOUT=${TIMEOUT-60}
APP_ROOT=/path/to/your/app/current
PID=$APP_ROOT/tmp/pids/unicorn.pid
ENVIRONMENT=production
APP_USER = edoctor
CMD="cd $APP_ROOT; bundle exec unicorn -E $ENVIRONMENT -D -c $APP_ROOT/config/unicorn.rb"
action="$1"
set -u

old_pid="$PID.oldbin"

cd $APP_ROOT || exit 1

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

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

workersig () {
  workerpid="$APP_ROOT/tmp/pids/unicorn.$2.pid"
  test -s "$workerpid" && kill -$1 `cat $workerpid`
}

case $action in
start)
  sig 0 && echo >&2 "Already running" && exit 0
  su $APP_USER -c "$CMD"
  ;;
stop)
  sig QUIT && exit 0
  echo >&2 "Not running"
  ;;
force-stop)
  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 $APP_USER -c "$CMD"
  ;;
upgrade)
  if sig USR2 && sleep 20 && sig 0 && oldsig QUIT
  then
    n=$TIMEOUT
    while test -s $old_pid && test $n -ge 0
    do
      printf '.' && sleep 1 && n=$(( $n - 1 ))
    done
    echo

    if test $n -lt 0 && test -s $old_pid
    then
      echo >&2 "$old_pid still exists after $TIMEOUT seconds"
      exit 1
    fi
    exit 0
  fi
  echo >&2 "Couldn't upgrade, starting '$CMD' instead"
  su $APP_USER -c "$CMD"
  ;;
kill_worker)
  workersig QUIT $2 && exit 0
  echo >&2 "Worker not running"
  ;;

reopen-logs)
  sig USR1
  ;;
*)
  echo >&2 "Usage: $0 <start|stop|restart|upgrade|force-stop|reopen-logs>"
  exit 1
  ;;
esac

unicorn.rb

APP_ROOT = File.expand_path(File.dirname(File.dirname(__FILE__)))

if ENV['MY_RUBY_HOME'] && ENV['MY_RUBY_HOME'].include?('rvm')
  begin
    rvm_path = File.dirname(File.dirname(ENV['MY_RUBY_HOME']))
    rvm_lib_path = File.join(rvm_path, 'lib')
    #$LOAD_PATH.unshift rvm_lib_path
    require 'rvm'
    RVM.use_from_path! APP_ROOT
  rescue LoadError
    raise "RVM ruby lib is currently unavailable."
  end
end

ENV['BUNDLE_GEMFILE'] = File.expand_path('../Gemfile', File.dirname(__FILE__))
require 'bundler/setup'

worker_processes 1
working_directory APP_ROOT

preload_app true

timeout 30

listen APP_ROOT + "/tmp/sockets/unicorn.sock", :backlog => 64

pid APP_ROOT + "/tmp/pids/unicorn.pid"

stderr_path APP_ROOT + "/log/unicorn.stderr.log"
stdout_path APP_ROOT + "/log/unicorn.stdout.log"

before_fork do |server, worker|
  defined?(ActiveRecord::Base) && ActiveRecord::Base.connection.disconnect!

  old_pid = Rails.root + '/tmp/pids/unicorn.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
      puts "Old master alerady dead"
    end
  end
end

after_fork do |server, worker|
  defined?(ActiveRecord::Base) && ActiveRecord::Base.establish_connection
  child_pid = server.config[:pid].sub('.pid', ".#{worker.nr}.pid")
  system("echo #{Process.pid} > #{child_pid}")
end

unicorn_worker_0.monitrc

check process unicorn_worker_0
with pidfile /path/to/your/app/shared/pids/unicorn.0.pid
start program = "/etc/init.d/app_unicorn start"
stop program = "/etc/init.d/app_unicorn stop"
if mem is greater than 175.0 MB for 1 cycles then restart
if cpu is greater than 22% for 2 cycles then alert         
if cpu is greater than 25% for 1 cycles then restart