Rails App维护而不妨碍访客

Question

Phusion Passenger错误消息不是我希望访问者在我更新后端时登陆我的网站时看到的内容.

那么我该如何解决这个问题呢？我的部署过程从一开始就存在缺陷吗？还是有什么我错过了？

这是我的部署过程,所以你得到了图片:

• 提交git仓库的新更新并推送到远程
• 上限部署
• ssh [ip]
• 耙宝石:安装
• rake db:migrate
• 黄瓜

cap部署和db:migrate或gems:install之间的时间是出现错误消息或更长时间的维护期间.

在我写这篇文章的过程中,一个想法让我头晕目眩:我可以将这些命令放入我的部署配方吗？

但是,如果维护需要30分钟或一小时,那么这些命令将无法解决问题.如何在这段时间内为访客提供维护启动页面？

提前致谢.

Answer 1

如果应用程序暂时不可用,您应该建立一个维护页面.我使用这个Capistrano任务:

namespace :deploy do
  namespace :web do
    desc <<-DESC
      Present a maintenance page to visitors. Disables your application's web \
      interface by writing a "maintenance.html" file to each web server. The \
      servers must be configured to detect the presence of this file, and if \
      it is present, always display it instead of performing the request.

      By default, the maintenance page will just say the site is down for \
      "maintenance", and will be back "shortly", but you can customize the \
      page by specifying the REASON and UNTIL environment variables:

        $ cap deploy:web:disable \\
              REASON="a hardware upgrade" \\
              UNTIL="12pm Central Time"

      Further customization will require that you write your own task.
    DESC
    task :disable, :roles => :web do
      require 'erb'
      on_rollback { run "rm #{shared_path}/system/maintenance.html" }

      reason = ENV['REASON']
      deadline = ENV['UNTIL']      
      template = File.read('app/views/admin/maintenance.html.erb')
      page = ERB.new(template).result(binding)

      put page, "#{shared_path}/system/maintenance.html", :mode => 0644
    end
  end
end

该app/views/admin/maintenance.html.erb文件应包含:

<p>We’re currently offline for <%= reason ? reason : 'maintenance' %> as of <%= Time.now.utc.strftime('%H:%M %Z') %>.</p>
<p>Sorry for the inconvenience. We’ll be back <%= deadline ? "by #{deadline}" : 'shortly' %>.</p>

最后一步是为Apache虚拟主机配置一些指令来查找maintenance.html文件并将所有请求重定向到它(如果存在):

<IfModule mod_rewrite.c>
  RewriteEngine On

  # Redirect all requests to the maintenance page if present
  RewriteCond %{REQUEST_URI} !\.(css|gif|jpg|png)$
  RewriteCond %{DOCUMENT_ROOT}/system/maintenance.html -f
  RewriteCond %{SCRIPT_FILENAME} !maintenance.html
  RewriteRule ^.*$ /system/maintenance.html [L]
</IfModule>

要将应用程序置于维护模式,运行cap deploy:web:disable并重新启动它cap deploy:web:enable.