自动化部署工具 Capistrano 与 Mina

├── current -> /var/www/your_app/releases/20141201042659
├── releases
│   ├── 20141201032351
│   ├── 20141201042256
│   ├── 20141201042659
├── repo
│   ├── branches
│   ├── hooks
│   ├── info
│   ├── objects
│   └── refs
└── shared
    ├── bin
    ├── bundle
    ├── config
    ├── log
    ├── public
    ├── tmp
    └── vendor

# Gemfile
gem 'capistrano', '~> 3.2.0'
gem 'capistrano-rails', '~> 1.1.0'
gem 'capistrano-bundler', '~> 1.1.0'
gem 'capistrano-rvm', '~> 0.1.0'
gem 'capistrano3-unicorn', '~> 0.2.0'
# Add this if you're using rbenv
# gem 'capistrano-rbenv', '~> 2.0.0'

├── Capfile                   # Cap 配置文件
├── config
│   ├── deploy
│   │   ├── production.rb     # 不同环境的部署配置
│   │   └── staging.rb
│   └── deploy.rb             # 公共变量
└── lib
    └── capistrano
            └── tasks         # 一些自定义的 task

require 'capistrano/setup'               # 加载 Cap 的 DSL
require 'capistrano/deploy'              # 加载 Cap 的 Workflow
require 'capistrano/rvm'                 # 加载 RVM 相关配置
# require 'capistrano/rbenv'             # 加载 Rbenv 相关配置
require 'capistrano/bundler'             # 加载 Bundle, 以便完成 bundle install
require 'capistrano/rails/assets'        # 加载 Rails 的 js, css 文件预编译
require 'capistrano/rails/migrations'    # 加载 Rails 的数据库自动迁移
require 'capistrano3/unicorn'            # 加载 Unicorn 服务

Dir.glob('lib/capistrano/tasks/*.rake').each { |r| import r }

cap unicorn:add_worker               # 增加一个 Unicorn Worker
cap unicorn:duplicate                # Restart
cap unicorn:legacy_restart           # 传统方式 Restart, 使用 USR2 + QUIT
cap unicorn:reload                   # Reload
cap unicorn:remove_worker            # 减少一个 Unicorn Worker
cap unicorn:restart                  # 无缝 Restart, 使用 USR2
cap unicorn:start                    # 启动 Unicorn
cap unicorn:stop                     # 关闭 Unicorn (QUIT)

# config valid only for Capistrano 3.1
lock '3.2.1'

set :application, 'your app name'     # 设置部署项目的名字
set :repo_url, '[email protected]'          # 设置项目的 git repo
set :deploy_to, "/var/www/xxx"        # 设置部署目录
set :deploy_user, 'deploy'            # 设置部署时的用户

set :scm, :git
set :format, :pretty
set :pty, true

# linked_dirs
# 是将项目的指定目录 link 到 shared 目录中, 这个操作会在从 repo 取下代码之后进行.
# 比如 log 目录, 每次部署完毕后新的版本中的 log 目录都会 link 到 shared/log 下
set :linked_dirs, %w{bin log tmp/pids tmp/cache tmp/sockets vendor/bundle public/system}

# linked_files
# 它是将 shared 目录中的文件 link 到项目中, 文件要首先存在于 shared 目录中, 不然 deploy 时会报错
# 在 Rails 项目中, 主要就是 database.yml, secret.yml 这样的敏感文件
set :linked_files, %w{config/database.yml}

# rvm_type
# :auto (default): just tries to find the correct path. ~/.rvm wins over /usr/local/rvm
# :system: defines the RVM path to /usr/local/rvm
# :user: defines the RVM path to ~/.rvm
set :rvm_type, :system
set :rvm_ruby_version, '2.1.2'
set :rvm_roles, [:app, :web, :db]

set :keep_releases, 10   # 最多存放十个部署版本

namespace :deploy do

  # 自定义了一个部署任务, 即自动运行 rake RAILS_ENV=rails_env db:create
  # 其中 release_path 指的是当前 release 目录
  # `fetch(:rails_env)` 读取配置中的 rails_env 变量, 并在 rake 命令中带上 env 变量
  task :create_database do
    on roles(:db) do
      within release_path do
        with rails_env: fetch(:rails_env) do
          execute :rake, 'db:create'
        end
      end
    end
  end

  before :migrate, :create_database     # 在每次 rake db:migrate 前都运行 rake db:create
  after  :finishing, 'deploy:cleanup'   # 在每次部署完毕后, 清理部署时生成的 tmp 文件及多余的版本
end

# Production Stage
set :stage, :production       # 设置 stage
set :branch, 'master'         # 设置 git branch
set :rails_env, :production   # 设置 rails_env

# 以下几个 server 会同时部署
server 'xxx.xxx.xxx.xxx', user: 'deploy', roles: %w(web app db), primary: true
server 'xxx.xxx.xxx.xxx', user: 'deploy', roles: %w(web app db)

deploy
  deploy:starting
    [before]
      deploy:ensure_stage
      deploy:set_shared_assets
    deploy:check                  # 检查 ssh, rvm/rbenv, linked_dirs, linked_files, git
  deploy:started
  deploy:updating
    git:create_release
    deploy:symlink:shared
  deploy:updated
    [before]
      deploy:bundle               # 重新 bundle install
    [after]
      deploy:migrate              # rake db:migrate
      deploy:compile_assets
      deploy:normalize_assets
  deploy:publishing
    deploy:symlink:release
    deploy:restart                # restart, 可自定义一些需要 restart 的服务
  deploy:published
  deploy:finishing
    deploy:cleanup
  deploy:finished
    deploy:log_revision

# Gemfile
gem 'mina', '~> 0.3'

require 'mina/bundler'
require 'mina/rails'
require 'mina/git'
# require 'mina/rbenv'  # for rbenv support. (http://rbenv.org)
# require 'mina/rvm'    # for rvm support. (http://rvm.io)

# Basic settings:
#   domain       - The hostname to SSH to.
#   deploy_to    - Path to deploy into.
#   repository   - Git repo to clone from. (needed by mina/git)
#   branch       - Branch name to deploy. (needed by mina/git)

set :domain, 'foobar.com'
set :deploy_to, '/var/www/foobar.com'
set :repository, 'git://...'
set :branch, 'master'

# Manually create these paths in shared/ (eg: shared/config/database.yml) in your server.
# They will be linked in the 'deploy:link_shared_paths' step.
set :shared_paths, ['config/database.yml', 'log']

# Optional settings:
#   set :user, 'foobar'    # Username in the server to SSH to.
#   set :port, '30000'     # SSH port number.

# This task is the environment that is loaded for most commands, such as
# `mina deploy` or `mina rake`.
task :environment do
  # If you're using rbenv, use this to load the rbenv environment.
  # Be sure to commit your .rbenv-version to your repository.
  # invoke :'rbenv:load'

  # For those using RVM, use this to load an RVM version@gemset.
  # invoke :'rvm:use[ruby-1.9.3-p125@default]'
end

# Put any custom mkdir's in here for when `mina setup` is ran.
# For Rails apps, we'll make some of the shared paths that are shared between
# all releases.
task :setup => :environment do
  queue! %[mkdir -p "#{deploy_to}/shared/log"]
  queue! %[chmod g+rx,u+rwx "#{deploy_to}/shared/log"]

  queue! %[mkdir -p "#{deploy_to}/shared/config"]
  queue! %[chmod g+rx,u+rwx "#{deploy_to}/shared/config"]

  queue! %[touch "#{deploy_to}/shared/config/database.yml"]
  queue  %[echo "-----> Be sure to edit 'shared/config/database.yml'."]
end

desc "Deploys the current version to the server."
task :deploy => :environment do
  deploy do
    # Put things that will set up an empty directory into a fully set-up
    # instance of your project.
    invoke :'git:clone'
    invoke :'deploy:link_shared_paths'
    invoke :'bundle:install'
    invoke :'rails:db_migrate'
    invoke :'rails:assets_precompile'

    to :launch do
      queue "touch #{deploy_to}/tmp/restart.txt"
    end
  end
end

# For help in making your deploy script, see the Mina documentation:
#
#  - http://nadarei.co/mina
#  - http://nadarei.co/mina/tasks
#  - http://nadarei.co/mina/settings
#  - http://nadarei.co/mina/helpers