Unicorn Deploy with Capistrano

.gitignore

## other files ommited

config/deploy.rb
config/unicorn.rb
config/nginx.conf
config/unicorn_init.sh

config_deploy.rb

require "bundler/capistrano"

server "SERVER_ADDRESS", :web, :app, :db, primary: true

set :application, "APP_NAME"
set :user, "APP_USER"
set :deploy_to, "/home/#{user}/apps/#{application}"
set :deploy_via, :remote_cache
set :use_sudo, false

set :scm, "git"
set :repository,  "GIT_REPOSITORY"
set :branch, "BRANCH"

set :unicorn_init, "unicorn_APPNAME"

set :pid_path, "#{shared_path}/pids/unicorn.pid"
set :socket_path, "/tmp/APPNAME.unicorn.sock"


default_run_options[:pty]  = true
ssh_options[:forward_agent] = true


after "deploy:restart", "deploy:cleanup"

namespace :deploy do
  %w[start stop restart].each do |command|
    desc "#{command} unicorn server"
    task command, roles: :app, except: {no_release: true} do
      sudo "service #{unicorn_init} #{command}"
    end
  end

  task :setup_config, roles: :app do
    sudo "ln -nfs #{current_path}/config/nginx.conf /etc/nginx/sites-enabled/#{application}"
    run "mkdir -p #{shared_path}/config"
    ## or config/database.yml if you are using ActiveRecord
    put File.read("config/mongoid.yml"), "#{shared_path}/config/mongoid.yml"
    put File.read("config/unicorn.rb"), "#{shared_path}/config/unicorn.rb"
    put File.read("config/nginx.conf"), "#{shared_path}/config/nginx.conf"
    put File.read("config/unicorn_init.sh"), "#{shared_path}/config/unicorn_init.sh"
    run "cd #{shared_path} && chmod +x config/unicorn_init.sh"
    sudo "#ln -nfs #{shared_path}/config/unicorn_init.sh /etc/init.d/#{unicorn_init}"
    sudo "#update-rc.d -f #{unicorn_init} defaults"
    puts "Now edit the config files in #{shared_path}."
  end
  after "deploy:setup", "deploy:setup_config"

  task :symlink_config, roles: :app do
    ## or config/database.yml if you are using ActiveRecord
    run "ln -nfs #{shared_path}/config/mongoid.yml #{release_path}/config/mongoid.yml"
    run "ln -nfs #{shared_path}/config/unicorn.rb #{release_path}/config/unicorn.rb"
    run "ln -nfs #{shared_path}/config/nginx.conf #{release_path}/config/nginx.conf"
    run "ln -nfs #{shared_path}/config/unicorn_init.sh #{release_path}/config/unicorn_init.sh"
  end
  after "deploy:finalize_update", "deploy:symlink_config"

  desc "Make sure local git is in sync with remote."
  task :check_revision, roles: :web do
    unless `git rev-parse HEAD` == `git rev-parse origin/BRANCH`
      puts "WARNING: HEAD is not the same as origin/BRANCH"
      puts "Run `git push` to sync changes."
      exit
    end
  end
  before "deploy", "deploy:check_revision"
end


after "deploy:update", "unicorn:restart"

# Unicorn tasks
namespace :unicorn do
  def check_pid_path_then_run(command)
    run <<-CMD
      if [ -s #{pid_path} ]; then
        #{command}
      else
        echo "Unicorn master worker wasn't found, possibly wasn't started at all. Try run unicorn:start first";
      fi
    CMD
  end

  desc "Starts the Unicorn server"
  task :start do
    run "mkdir -p #{File.dirname(pid_path)}"
    run "mkdir -p #{File.dirname(socket_path)}"
    run <<-CMD
      if [ ! -s #{pid_path} ]; then
        #{try_sudo} service #{unicorn_init} start        
      else
        echo "Unicorn is already running at PID: `cat #{pid_path}`";
      fi
    CMD
  end

  desc "Stops Unicorn server"
  task :stop do
    run "#{try_sudo} service #{unicorn_init} stop"
  end

  desc "Zero-downtime restart of Unicorn"
  task :restart, :roles => :app, :except => { :no_release => true } do
    check_pid_path_then_run "#{try_sudo} kill -USR2 `cat #{pid_path}`;"
  end
end

config_nginx.conf

upstream unicorn {
  server unix:/tmp/APP_NAME.unicorn.sock fail_timeout=0;
}

server {
  listen 80 default deferred;
  server SERVER_NAME.COM;
  root APP_PATH/public;

  location ^~ /assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;
  }

  try_files $uri/index.html $uri @unicorn;
  location @unicorn {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://unicorn;
  }

  error_page 500 502 503 504 /500.html;
  client_max_body_size 4G;
  keepalive_timeout 10;
}

config_unicorn.rb

working_directory "APP_PATH"
pid "APP_PATH/tmp/pids/valorescarros.unicorn.pid"
stderr_path "APP_PATH/unicorn.log"
stdout_path "APP_PATH/log/unicorn.log"

listen "/tmp/APP_NAME.unicorn.sock"
worker_processes 2
timeout 30

preload_app true

before_fork do |server, worker|
  if defined? ActiveRecord::Base
    ActiveRecord::Base.connection.disconnect!
  end
  # Quit the old unicorn process
  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
  sleep 1
end

after_fork do |server, worker|
  # Start up the database connection again in the worker
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection
  end
end

config_unicorn_init.sh

#!/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=${TIMEOUT-60}
APP_ROOT=APP_PATH/current
PID=$APP_ROOT/tmp/pids/unicorn.pid
CMD="/usr/local/bin/unicorn -D -c $APP_ROOT/config/unicorn.rb -E production"
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`
}

case $action in
start)
  sig 0 && echo >&2 "Already running" && exit 0
  $CMD
  ;;
stop)
  sig QUIT && exit 0
  echo >&2 "Not running"
  ;;
force-stop)
  sig TERM && exit 0
  echo >&2 "Not running"
  ;;
restart|reload)
  sig HUP && echo reloaded OK && exit 0
  echo >&2 "Couldn't reload, starting '$CMD' instead"
  $CMD
  ;;
upgrade)
  if sig USR2 && sleep 2 && sig 0 && oldsig QUIT
  then
    n=$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"
  $CMD
  ;;
reopen-logs)
  sig USR1
  ;;
*)
  echo >&2 "Usage: $0 <start|stop|restart|upgrade|force-stop|reopen-logs>"
  exit 1
  ;;
esac