简化gem安装

Ruby on Rails项目往往用到大量第三方的gems,在项目有新成员加入，或配置新的开发系统时，一个个的安装是件很繁琐的事情。

我用的办法就是写一个自己的gem,让它依赖于项目里用到的其他gems。这样的话，安装这个gem的时候，就会顺带把其他gems安装了。

代码非常简单：

>cat install-gems.gemspec
#
#Usage:
#gem build install-gems.gemspec
#gem install install-gems.0.0.1.gem
#gem uninstall install-gems (optional, remove this useless gem)
#
spec = Gem::Specification.new do |s|
  s.name = "install-gems"
  s.version = "0.0.1"
  s.author = "yawl"
  s.email = "yawl@iteye.com"
  s.homepage = "http://xruby.iteye.com"
  s.platform = Gem::Platform::RUBY
  s.summary = "This gem has no content in itself, it helps to install all the gems we depend on"
  s.add_dependency('actionmailer', '>=2.0.2')
  s.add_dependency('actionpack', '>=2.0.2')
  s.add_dependency('activerecord', '>=2.0.2')
  s.add_dependency('activeresource', '>=2.0.2')
  s.add_dependency('activesupport', '>=2.0.2')
  s.add_dependency('acts_as_ferret', '>=0.4.3')
  s.add_dependency('capistrano', '>=2.1.0')
  s.add_dependency('mysql', '>=2.7')
  s.add_dependency('rails', '>=2.0.2')
  s.add_dependency('rake', '>=0.8.1')
  # add more here
end

恩，这个办法不错

Hmm, 内部gemserver这个时候就很好用了

rails 2.1将内建支持该特性...
http://ryandaigle.com/articles/2008/4/1/what-s-new-in-edge-rails-gem-dependencies

# environment.rb实例

Rails::Initializer.run do |config| 
  # config.gem "bj"
  # config.gem "hpricot", :version => '0.6', :source => "http://code.whytheluckystiff.net" 
  # Require a gem that needs to require a file different than the gem's name
  # config.gem "aws-s3", :lib => "aws/s3"
  config.gem "tzinfo", :version => '>= 0.3.8'
  config.gem "ambition", :version => '>= 0.5.2'
  config.gem "ambitious-activerecord", :version => '>= 0.1.1', 
                                       :lib => 'ambition/adapters/active_record'

  # 或者如下写法
  gem 'will_paginate', '~> 2.2.1'
  require 'will_paginate'

 # 用法
  # rake gems             # List the gems that this rails application depends on
  # rake gems:install     # Installs all required gems for this application.
  # rake gems:unpack      # Unpacks all gems into vendor/gems.
  # rake gems:unpack:dependencies      # Unpack all dependencies
  # rake gems:unpack:dependencies GEM=foo #Unpack all dependencies for gem foo
  # rake gems:build       # for build native extensions.

end 

用了一下2.1的这个功能还不错。

一个小问题就是gem安装需要root权限，而我们自动deploy时是以普通用户进行的，所以没有把'rake gems:install'加到脚本里。

我知道可以把sudo设成不要密码，或者把gem安装目录的权限改了。但从安全的考虑都不愿意实施。

rake gems:unpack      # Unpacks all gems into vendor/gems.

嗯，这个好。