Rails Unicorn Nginx Guide

目前，基于 Rails 框架搭建 Web 服务，比较成熟的技术路线是使用 Nginx 和 Unicorn。 前者为 Web Server, 或者为 Rails Server。淘汰 Apache 和 Passenger。
下面介绍一下三者如何配置, 更详细的配置请参考： My Colleges Project

1. Rails Gemfile 配置

    gem 'unicorn'

    group :development do
      gem 'capistrano'
    end
  

2. Unicorn 配置
新建文件：/app/config/unicorn.rb

    module Rails
      class << self
        def root
          File.expand_path(__FILE__).split('/')[0..-3].join('/')
        end
      end
    end
    rails_env = ENV["RAILS_ENV"] || "development"

    preload_app true
    working_directory Rails.root
    pid "#{Rails.root}/tmp/pids/unicorn.pid"
    stderr_path "#{Rails.root}/log/unicorn.log"
    stdout_path "#{Rails.root}/log/unicorn.log"

    listen 5000, :tcp_nopush => false

    if rails_env == "production"
      worker_processes 4
    else
      worker_processes 1
    end
    timeout 120

    if GC.respond_to?(:copy_on_write_friendly=)
      GC.copy_on_write_friendly = true
    end

    before_exec do |server|
      ENV['BUNDLE_GEMFILE'] = "#{Rails.root}/Gemfile"
    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

      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 "Send 'QUIT' signal to unicorn error!"
        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
  

3. Capistrano 配置
文件目录：/app/config/deploy.rb

    # unicorn.rb 路径
    set :unicorn_path, "#{deploy_to}/current/config/unicorn.rb"

    namespace :deploy do
      task :start, :roles => :app do
        run "cd #{deploy_to}/current/; RAILS_ENV=production bundle exec unicorn_rails -c #{unicorn_path} -D"
      end

      task :stop, :roles => :app do
        run "kill -QUIT `cat #{deploy_to}/current/tmp/pids/unicorn.pid`"
      end

      desc "Restart Application"
      task :restart, :roles => :app do
        run "kill -USR2 `cat #{deploy_to}/current/tmp/pids/unicorn.pid`"
      end
    end
  

4. Nginx 配置
文件目录：/path/nginx/conf/nginx.conf

   server {
     listen 80;
     server_name www.mycollege.com;

     location ~* .(jpg|png|bmp|gif)$ {
      root /path/public;
     }

       location / {
          proxy_redirect     off;
          proxy_set_header   Host             $host;
          proxy_set_header   X-Forwarded-Host $host;
          proxy_set_header   X-Forwarded-Server $host;
          proxy_set_header   X-Real-IP        $remote_addr;
          proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
          proxy_buffering    on;
          proxy_pass  http://host:5000;
          access_log logs/access.log combined;
       }
   }
  

5. 启动脚本
参考网上 Shell 大牛写的脚本 unicorn.sh，方便操作 unicorn 进程，对其进行： start, restart, stop.

2013-07-08