Gem capistrano 简易速成部署方案 (含 deploy.rb 模板)
先在这里放上来自《Agile Web Development with Rails 4th for Rails3.2》的一个 deploy.rb 模板：
# be sure to change these
set:user, 'rubys'
set:domain, 'depot.pragprog.com'
set:application, 'depot'
# adjust if youareusing RVM, remove if youarenot
$:.unshift(File.expand_path('./lib', ENV['rvm_path']))
require "rvm/capistrano"
set:rvm_ruby_string, '1.9.2'
set:rvm_type, :user
# file paths
set:repository, "#{user}@#{domain}:git/#{application}.git"
set:deploy_to, "/home/#{user}/#{domain}"
# distribute your applications across servers (the instructions below putthem
# allon thesame server, defined above as 'domain', adjust as necessary)
role :app, domain
role :web, domain
role :db, domain, :primary => true
# youmight need to setthis if youaren't seeing password prompts
# default_run_options[:pty] = true
# As Capistrano executes in a non-interactive mode andtherefore doesn't cause
# anyof your shell profile scripts to be run, thefollowing might be needed
# if (for example) youhave locally installed gems or applications. Note:
# this needs to contain thefull values forthevariables set, notsimply
# thedeltas.
# default_environment['PATH']='<your paths>:/usr/local/bin:/usr/bin:/bin'
# default_environment['GEM_PATH']='<your paths>:/usr/lib/ruby/gems/1.8'
# miscellaneous options
set:deploy_via, :remote_cache
set:scm, 'git'
set:branch, 'master'
set:scm_verbose, true
set:use_sudo, false
set:rails_env, :production
namespace :deploy do
desc "cause Passenger to initiate a restart"
task :restart do
run"touch #{current_path}/tmp/restart.txt"
end
desc "reload thedatabase with seed data"
task :seed do
run"cd#{current_path}; rake db:seed RAILS_ENV=#{rails_env}"
end
end
after "deploy:update_code", :bundle_install
desc "install thenecessary prerequisites"
task :bundle_install, :roles => :app do
run"cd#{release_path} && bundle install"
end
这个模板非常方便，因为我拿在手里了，加上自己的配置就可以直接使用了。 现在这里我介绍一下怎么使用，需要修改一些什么。
首先在加入一个 gem，gem 'capistrano'。然后创建相关文件，只需要执行一个命令就可以：
$ capify .
[add] writing './Capfile'
[add] writing './config/deploy.rb'
[done] capified!
这时候生成两个文件。如果在用使用 3.1 以上版本的 Rails，在 Capfile 加上一句：
load 'deploy/assets' //assets操作
然后剩下的就是 deploy.rb 上的了，我发一下我的配置，然后备注一下，到时候大家按照我那个配置设置一下就可以了，如下：
require "bundler/capistrano" #部署时运行bundle
set :user, 'deploy' #存放web的用户名
set :domain, '106.XX.XX.XX' #服务器IP
set :application, 'ruby-china.org' #项目文件名，既将会在user里面创建这个名字的文件夹
# adjust if you are using RVM, remove if you are not
$:.unshift(File.expand_path('./lib', ENV['rvm_path']))
require "rvm/capistrano"
set :rvm_ruby_string, '1.9.3'
set :rvm_type, :user
# file paths
set :repository, "git@#{domain}:ruby-china.git" #git所存在的地址，我存放在自己的服务器中
set :deploy_to, "/home/deploy/ruby-china.org" #部署的地址
# distribute your applications across servers (the instructions below put them
# all on the same server, defined above as 'domain', adjust as necessary)
role :app, domain
role :web, domain
role :db, domain, :primary => true
ssh_options[:forward_agent] = true #forward_agent方式
# miscellaneous options
set :deploy_via, :remote_cache
set :scm, 'git'
set :branch, 'master'
set :scm_verbose, true
set :use_sudo, false
set :rails_env, "production"
namespace :deploy do
desc "cause Passenger to initiate a restart"
task :restart do
run "touch #{current_path}/tmp/restart.txt"
end
desc "reload the database with seed data"
task :seed do
run "cd #{current_path}; rake db:seed RAILS_ENV=#{rails_env}"
end
end
注意：这里涉及一个叫“forward_agent 方式”，简单的来说就是服务器在 clone git 的时候是不成功的，因为他的 ssh 公钥并不在 git 的账户中，而我们电脑的公钥已经存放在 git 服务器里了，所以可以直接 push 或者 pull 操作 git，所以这类需要使用 ssh agent forward，也就是在部署时，VPS 使用你的 SSH 密钥。参考： Using ssh agent forwarding
git 的地址当然也可以在 github 上，但是我觉得竟然有 VPS 了，放在自己的 VPS 上更加方便。我以前有个教人在自己 VPS 上部署 GIT 的方法：Linode VPS 小组级 Git 服务器搭建
如果你使用的个别东西不一样就需要参考 capistrano 的 wiki 进行修改了，例如你用的不是 git，服务器不是 Passenger 等等。
写好 deploy.rb 后的事情就不多了，首先把修改过的内容 push 到 git 上面。然后开始部署了，第一次部署需要运行：
$ cap deploy:setup
$ cap deploy:check
$ cap deploy:migrations
上条命令下来，如果没有问题就已经成功的设置成功了，然后进行发布：
$ cap deploy
非常方便的就把网站部署到 VPS 上了，如果以后有修改了东西也非常容易发布：
$ git add .
$ git commit -m "add capfiles"
$ git push
$ cap deploy
非常的简单方便，只需要几条命令，服务器上的信息就更新了。这个文章介绍的比较简单，没有去讲一些任务的写法，就简单的项目来说精简够用了。需要更深入的了解可以通过以上方式： Capistrano 2.x Getting Started capistrano wiki
after "deploy:update_code", :bundle_install
desc "install the necessary prerequisites"
task :bundle_install, :roles => :app do
run "cd #{release_path} && bundle install"
end
上面这部分有必要写吗？
require "bundler/capistrano" #部署时运行bundle 已经有这个了啊
https://github.com/carlhuda/bundler/blob/master/lib/bundler/capistrano.rb#L8
#1 楼 @happypeter 其实我也不太清楚什么原因，之前没有加require "bundler/capistrano"
第一次部署的时候他不会自动的 bundle install。
#1 楼 @happypeter 老师为什么 set :use_sudo, false 我在我的项目中也时 false 但一直无法成功，在你的视频里，我注意到你改成了 true ，不知道原因，求老师指教
set :use_sudo, false. By default, Capistrano will try to use sudo to do certain operations (setting up your servers, restarting your application, etc.). If you are on a shared host, sudo might be unavailable to you, or maybe you just want to avoid using sudo.
这个好像是与你的项目和 rvm 部署的关系吧。有些人把 rvm 部署到 root 里的，就需要 sudo 了。
#3 楼 @tiseheaini
I used #{try_sudo} in my deploy.rb whenever I want to run some command as root, and
-
#{try_sudo}will returnsudowhenset :use_sudo, true, - return
""(empty string) whenset :use_sudo, false
as clearly shown in the source code https://github.com/capistrano/capistrano/blob/master/lib/capistrano/recipes/deploy.rb#L155
@happypeter 我看到了这句话 always wanted sudo to run as a particular user, you could do set(:admin_runner, "bob"). 意思是说，我可以 set :admin_runner, "tian" 然后用我的账号去登陆系统，然后执行命令，还是说，先用 root 运行一些命令，然后再改回 false，以后的部署就不需要使用 root 了？？？
我的理解对吗？？
没太明白你的意思。
使用 root 是存在潜在风险的，因为 root 创建的东西，其他用户一般是没有权限去改动的。只要你记住这一点，你就可以安心的使用 sudo 了，方式很多效果都一样。
上面的 bob 必须是系统上的 sudoer 才可以。
@JeskTop 我的执行 migrations 报错，能帮我看看怎么回事吗？
* executing `deploy:migrations'
* executing `deploy:update_code'
updating the cached checkout on all servers
executing locally: "git ls-remote [email protected]:git/depot.git master"
command finished in 404ms
* executing "if [ -d /home/william/depot.linuxcbt.com/shared/cached-copy ]; then cd /home/william/depot.linuxcbt.com/shared/cached-copy && git fetch origin && git fetch --tags origin && git reset --hard a6c236f29dd7ca5547f9d4a371c1919227245a09 && git clean -d -x -f; else git clone [email protected]:git/depot.git /home/william/depot.linuxcbt.com/shared/cached-copy && cd /home/william/depot.linuxcbt.com/shared/cached-copy && git checkout -b deploy a6c236f29dd7ca5547f9d4a371c1919227245a09; fi"
servers: ["depot.linuxcbt.com"]
[depot.linuxcbt.com] executing command
** [depot.linuxcbt.com :: out] HEAD is now at a6c236f bundle gems
command finished in 1010ms
copying the cached version to /home/william/depot.linuxcbt.com/releases/20121104135345
* executing "cp -RPp /home/william/depot.linuxcbt.com/shared/cached-copy /home/william/depot.linuxcbt.com/releases/20121104135345 && (echo a6c236f29dd7ca5547f9d4a371c1919227245a09 > /home/william/depot.linuxcbt.com/releases/20121104135345/REVISION)"
servers: ["depot.linuxcbt.com"]
[depot.linuxcbt.com] executing command
command finished in 32ms
* executing `deploy:finalize_update'
triggering before callbacks for `deploy:finalize_update'
* executing `deploy:assets:symlink'
* executing "rm -rf /home/william/depot.linuxcbt.com/releases/20121104135345/public/assets &&\\\n mkdir -p /home/william/depot.linuxcbt.com/releases/20121104135345/public &&\\\n mkdir -p /home/william/depot.linuxcbt.com/shared/assets &&\\\n ln -s /home/william/depot.linuxcbt.com/shared/assets /home/william/depot.linuxcbt.com/releases/20121104135345/public/assets"
servers: ["depot.linuxcbt.com"]
[depot.linuxcbt.com] executing command
command finished in 8ms
* executing "chmod -R g+w /home/william/depot.linuxcbt.com/releases/20121104135345"
servers: ["depot.linuxcbt.com"]
[depot.linuxcbt.com] executing command
command finished in 10ms
* executing "rm -rf /home/william/depot.linuxcbt.com/releases/20121104135345/log /home/william/depot.linuxcbt.com/releases/20121104135345/public/system /home/william/depot.linuxcbt.com/releases/20121104135345/tmp/pids &&\\\n mkdir -p /home/william/depot.linuxcbt.com/releases/20121104135345/public &&\\\n mkdir -p /home/william/depot.linuxcbt.com/releases/20121104135345/tmp &&\\\n ln -s /home/william/depot.linuxcbt.com/shared/log /home/william/depot.linuxcbt.com/releases/20121104135345/log &&\\\n ln -s /home/william/depot.linuxcbt.com/shared/system /home/william/depot.linuxcbt.com/releases/20121104135345/public/system &&\\\n ln -s /home/william/depot.linuxcbt.com/shared/pids /home/william/depot.linuxcbt.com/releases/20121104135345/tmp/pids"
servers: ["depot.linuxcbt.com"]
[depot.linuxcbt.com] executing command
command finished in 15ms
* executing "find /home/william/depot.linuxcbt.com/releases/20121104135345/public/images /home/william/depot.linuxcbt.com/releases/20121104135345/public/stylesheets /home/william/depot.linuxcbt.com/releases/20121104135345/public/javascripts -exec touch -t 201211041353.45 {} ';'; true"
servers: ["depot.linuxcbt.com"]
[depot.linuxcbt.com] executing command
*** [err :: depot.linuxcbt.com] find: `/home/william/depot.linuxcbt.com/releases/20121104135345/public/images'
*** [err :: depot.linuxcbt.com] : No such file or directory
*** [err :: depot.linuxcbt.com] find: `/home/william/depot.linuxcbt.com/releases/20121104135345/public/stylesheets': No such file or directory
*** [err :: depot.linuxcbt.com] find: `/home/william/depot.linuxcbt.com/releases/20121104135345/public/javascripts': No such file or directory
command finished in 14ms
triggering after callbacks for `deploy:update_code'
* executing `deploy:assets:precompile'
* executing "cd /home/william/depot.linuxcbt.com/releases/20121104135345 && rake RAILS_ENV=production RAILS_GROUPS=assets assets:precompile"
servers: ["depot.linuxcbt.com"]
[depot.linuxcbt.com] executing command
*** [err :: depot.linuxcbt.com] sh: 1: rake: not found
command finished in 11ms
failed: "sh -c 'cd /home/william/depot.linuxcbt.com/releases/20121104135345 && rake RAILS_ENV=production RAILS_GROUPS=assets assets:precompile'" on depot.linuxcbt.com
前面的命令都没有报错
*** [err :: depot.linuxcbt.com] find: `/home/william/depot.linuxcbt.com/releases/20121104135345/public/images'
*** [err :: depot.linuxcbt.com] : No such file or directory
*** [err :: depot.linuxcbt.com] find: `/home/william/depot.linuxcbt.com/releases/20121104135345/public/stylesheets': No such file or directory
*** [err :: depot.linuxcbt.com] find: `/home/william/depot.linuxcbt.com/releases/20121104135345/public/javascripts': No such file or directory
command finished in 14ms
在这里报错的，不知道为什么会提示你没有/images，/stylesheets，/javascripts 这 3 个文件夹。 http://stackoverflow.com/questions/3023857/capistrano-and-deployment-of-a-website-from-github 这里有解决方法，不太理解为什么你那会出现这个问题呢？
谢谢分享，成功部署. 但是有个问题，线上的 database.yml 和本地开发用的是不一样。 而且 database.yml 是放在了 gitignore 里面了的，git 管理的是 database.yml. 我想问这种情况在部署的时候怎么操作呢？ 是否在第一次运行 cap deploy 后，然后手动登上服务器，跑到 current 目录下面去，修改 database.yml?
$:.unshift(File.expand_path('./lib', ENV['rvm_path'])) 这句是做什么用的，我加上这句后会报错，然后去掉后就可以了~
