使用Unicorn,nginx,Capistrano 部署你的Rails 应用

http://rubysource.com/deploying-your-rails-app-to-the-cloud-with-unicorn-nginx-and-capistrano/

配置你的服务器

你需要在你的服务器上安装Ruby的环境，你可以使用RVM或者是rbenv.

上传到github

这步需要将你的应用上传到github,在你的github上创建新的repository,然后在你本机代码位置执行下面的命令，初始化git仓库。

git init
git add .
git commit -m "<message>"
git remote add origin [email protected]:<username>/<git repo>.git
git push origin master

安装Capistrano

在你的Gemfile里添加下面的一行。

gem 'capistrano'

然后执行

bundle

在你的项目目录里执行

capify .

执行结果

examination-paper ➤ capify .                                                                                                                      git:master*
[add] writing './Capfile'
[add] writing './config/deploy.rb'
[done] capified!

创建了两个文件，你的Rails应用的配置文件写在config/deploy.rb里。下面是一个示例。

require "bundler/capistrano"

# Define your server here
server "<server>", :web, :app, :db, primary: true

# Set application settings
set :application, "<app_name>"
set :user, "<deployment_user>" # As defined on your server
set :deploy_to, "/home/#{user}/apps/#{application}" # Directory in which the deployment will take place
set :deploy_via, :remote_cache
set :use_sudo, false

set :scm, "git"
set :repository, "[email protected]:<git_user>/#{application}.git"
set :branch, "master"

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

after "deploy", "deploy:cleanup" # keep only the last 5 releases

namespace :deploy do
  %w[start stop restart].each do |command|
    desc "#{command} unicorn server"
    task command, roles: :app, except: {no_release: true} do
      run "/etc/init.d/unicorn_#{application} #{command}" # Using unicorn as the app server
    end
  end

  task :setup_config, roles: :app do
    sudo "ln -nfs #{current_path}/config/nginx.conf /etc/nginx/sites-enabled/#{application}"
    sudo "ln -nfs #{current_path}/config/unicorn_ini.sh /etc/init.d/unicorn_#{application}"
    run "mkdir -p #{shared_path}/config"
    put File.read("config/database.yml"), "#{shared_path}/config/database.yml"
    puts "Now edit the config files in #{shared_path}."
  end
  after "deploy:setup", "deploy:setup_config"

  task :symlink_config, roles: :app do
    run "ln -nfs #{shared_path}/config/database.yml #{release_path}/config/database.yml"
  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/master`
      puts "WARNING: HEAD is not the same as origin/master"
      puts "Run `git push` to sync changes."
      exit
    end
  end
  before "deploy", "deploy:check_revision"
end

deploy.rb 文件，使用unicorn 作为server,配置文件nginx.conf和unicorn.rb 例子如下：

upstream unicorn {
  server unix:/tmp/unicorn.<app_name>.sock fail_timeout=0;
}

server {
	listen 80 default deferred;
	server_name <your_servername>;
	if ($host = '<your_servername>' ) {
		rewrite ^/(.*)$ http://<your_servername>/$1 permanent;
	}
  root /home/deployer/apps/<app_name>/current/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;
}

unicorn.rb

# Define your root directory
root = "/home/deployer/apps/gifroll/current"

# Define worker directory for Unicorn
working_directory root

# Location of PID file
pid "#{root}/tmp/pids/unicorn.pid"

# Define Log paths
stderr_path "#{root}/log/unicorn.log"
stdout_path "#{root}/log/unicorn.log"

# Listen on a UNIX data socket
listen "/tmp/unicorn.gifroll.sock"

# 16 worker processes for production environment
worker_processes 16

# Load rails before forking workers for better worker spawn time
preload_app true

# Restart workes hangin' out for more than 240 secs
timeout 240

最后

在config目录里，创建unicorn_init.sh ，添加下面的内容

#!/bin/sh
### BEGIN INIT INFO
# Provides:          unicorn
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Manage unicorn server
# Description:       Start, stop, restart unicorn server for a specific application.
### END INIT INFO
set -e

# Feel free to change any of the following variables for your app:
TIMEOUT=${TIMEOUT-60}
APP_ROOT=/home/deployer/apps/<app_name>/current
PID=$APP_ROOT/tmp/pids/unicorn.pid
CMD="cd $APP_ROOT; bundle exec unicorn -D -c $APP_ROOT/config/unicorn.rb -E production"
AS_USER=<user>
set -u

OLD_PIN="$PID.oldbin"

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

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

run () {
  if [ "$(id -un)" = "$AS_USER" ]; then
    eval $1
  else
    su -c "$1" - $AS_USER
  fi
}

case "$1" in
start)
  sig 0 && echo >&2 "Already running" && exit 0
  run "$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 '$CMD' instead"
  run "$CMD"
  ;;
upgrade)
  if sig USR2 && sleep 2 && sig 0 && oldsig QUIT
  then
    n=$TIMEOUT
    while test -s $OLD_PIN && test $n -ge 0
    do
      printf '.' && sleep 1 && n=$(( $n - 1 ))
    done
    echo

    if test $n -lt 0 && test -s $OLD_PIN
    then
      echo >&2 "$OLD_PIN still exists after $TIMEOUT seconds"
      exit 1
    fi
    exit 0
  fi
  echo >&2 "Couldn't upgrade, starting '$CMD' instead"
  run "$CMD"
  ;;
reopen-logs)
  sig USR1
  ;;
*)
  echo >&2 "Usage: $0 <start|stop|restart|upgrade|force-stop|reopen-logs>"
  exit 1
  ;;
esac

我们如何部署我们的应用呢？ 

把你最新的改动push到github,然后执行下面的命令

cap deploy:setup

这个命令会在你的服务器   /<user>/apps/<app_name> 创建两个文件夹，然后把nginx和unicorn的配置文件链接到合适的位置。

你需要给服务器访问git 代码库的权限。

ssh-add

执行下面的命令部署

cap deploy:cold

cold部署会执行迁移并且重启web服务.