sv-rails-application-run.erb

#!/bin/bash
#
# This file is managed by Chef, using the <%= node.name %> cookbook.
# Editing this file by hand is highly discouraged!
#

# Copyright (c) 2014 Jean Mertz <[email protected]>
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#

exec 2>&1

#
# Since unicorn creates a new pid on restart/reload, it needs a little extra
# love to manage with runit. Instead of managing unicorn directly, we simply
# trap signal calls to the service and redirect them to unicorn directly.
#

RUNIT_PID=$$
APPLICATION_NAME=<%= @options[:app].application.name %>
APPLICATION_PATH=<%= File.join(@options[:app].path, 'current') %>
BUNDLE_CMD="<%= @options[:bundler] ? "#{@options[:bundle_command]} exec" : '' %>"
UNICORN_CMD=<%= @options[:smells_like_rack] ? 'unicorn' : 'unicorn_rails' %>
UNICORN_CONF=<%= File.join('/etc/unicorn', "#{@options[:app].application.name}.rb") %>
RAILS_ENV=<%= @options[:rails_env] %>
CUR_PID_FILE=<%= @options['pid'] %>
OLD_PID_FILE=$CUR_PID_FILE.oldbin

echo "Runit service restarted (PID: $RUNIT_PID)" 

function is_unicorn_alive {
  set +e
  if [ -n $1 ] && kill -0 $1 >/dev/null 2>&1; then
    echo "yes"
  fi
  set -e
}

if [ -e $OLD_PID_FILE ]; then
  OLD_PID=$(cat $OLD_PID_FILE)
  echo "Old master detected (PID: $OLD_PID), waiting for it to quit"
  while [ -n "$(is_unicorn_alive $OLD_PID)" ]; do
    sleep 5
  done
fi

if [ -e $CUR_PID_FILE ]; then
  CUR_PID=$(cat $CUR_PID_FILE)
  if [ -n "$(is_unicorn_alive $CUR_PID)" ]; then
    echo "Detected running Unicorn instance (PID: $CUR_PID)"
    RUNNING=true
  fi
fi

function start {
  unset ACTION
  if [ $RUNNING ]; then
    restart
  else
    echo 'Starting new unicorn instance'
    cd $APPLICATION_PATH

    $BUNDLE_CMD $UNICORN_CMD -c $UNICORN_CONF -E $RAILS_ENV -D
    sleep 3
    CUR_PID=$(cat $CUR_PID_FILE)
  fi
}

function stop {
  unset ACTION
  echo 'Initializing graceful shutdown'
  kill -QUIT $CUR_PID

  while [ -n "$(is_unicorn_alive $CUR_PID)" ]; do
    echo '.'
    sleep 2
  done

  echo 'Unicorn stopped, exiting Runit process'
  kill -9 $RUNIT_PID
}

function restart {
  unset ACTION
  echo "Restart request captured, swapping old master (PID: $CUR_PID) for new master with USR2"
  kill -USR2 $CUR_PID

  sleep 2
  echo 'Restarting Runit service to capture new master PID'
  exit
}

function alarm {
  unset ACTION
  echo 'Unicorn process interrupted'
}

trap 'ACTION=stop' STOP TERM KILL
trap 'ACTION=restart' QUIT USR2 INT
trap 'ACTION=alarm' ALRM

[ $RUNNING ] || ACTION=start

if [ $ACTION ]; then
  echo "Performing \"$ACTION\" action and going into sleep mode until new signal captured"
elif [ $RUNNING ]; then
  echo "Going into sleep mode until new signal captured"
fi

if [ $ACTION ] || [ $RUNNING ]; then
  while true; do
    [ "$ACTION" == 'start' ] && start
    [ "$ACTION" == 'stop' ] && stop
    [ "$ACTION" == 'restart' ] && restart
    [ "$ACTION" == 'alarm' ] && alarm
    sleep 2
  done
fi