如何为特定角色创建角色并运行 capistrano 任务？答案

【问题标题】：How to create roles and run capistrano tasks for specific roles?如何为特定角色创建角色并运行 capistrano 任务？
【发布时间】：2014-05-02 22:04:29
【问题描述】：

这是我在配置/部署中的 production.rb

Instance Details
server '198.61.179.237', :web, :app, :db, primary: true
server '198.61.228.160', :file_server

# Rails Environment
set :rails_env, 'production'

并且来自 deploy.rb

namespace :check do
  task :function_1, :roles => :web do
    puts 'function_1'
  end
  task :function_2, :roles => :file_server do
    puts 'filesssss'
  end
end

但是当我尝试这样做时

cap HOSTS=198.61.228.160 production check:function_2
cap HOSTS=198.61.228.160 production check:function_1

cap HOSTS=198.61.179.237 production check:function_2
cap HOSTS=198.61.179.237 production check:function_1

他们每个人都给出了各自的输出。但根据声明

function_1 应该只适用于:role => :web，同样function_2 应该只适用于:role => :file_server。

我哪里出错了？正确的方法是什么？

【问题讨论】：

标签： ruby-on-rails ruby-on-rails-4 capistrano roles role

【解决方案1】：

我相信你想要的是cap HOSTFILTER=198.61.228.160 function_2 或cap HOSTFILTER=198.61.179.237 function_1

这是因为 HOSTFILTER 检查所有具有功能角色的服务器和您正在寻找的服务器的交集。 here by Pete Hodgson 可以找到一个很好的解释

由于手册的原因，我们也可以看到这一点：

    $ cap -H

       HOSTS
            Execute the tasks against this comma-separated list of hosts.
            Effectively, this makes the host(s) part of every roles.

       HOSTFILTER
            Execute tasks against this comma-separated list of host, 
            but only if the host has the proper role for the task.

       HOSTROLEFILTER
            Execute tasks against the hosts in this comma-separated list of roles,
            but only if the host has the proper role for the task.

       ROLES
            Execute tasks against this comma-separated list of roles.  Hosts which
            do not have the right roles will be skipped.

【讨论】：