Added config.gem for specifying which gems are required by the application, as well as rake tasks for installing and freezing gems. [rick]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9140 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

5 files changed, 231 insertions, 2 deletions

diff --git a/railties/CHANGELOG b/railties/CHANGELOG
index 672131b96e..7950e6a14f 100644
--- a/railties/CHANGELOG
+++ b/railties/CHANGELOG
@@ -1,5 +1,22 @@
 *SVN*
 
+* Added config.gem for specifying which gems are required by the application, as well as rake tasks for installing and freezing gems. [rick]
+
+  Rails::Initializer.run do |config|
+    config.gems "bj"
+    config.gems "hpricot", :version => '0.6', :source => "http://code.whytheluckystiff.net"
+    config.gems "aws-s3", :lib => "aws/s3"
+  end
+  
+  # List required gems.
+  rake gems
+  
+  # Install all required gems:
+  rake gems:install
+  
+  # Unpack specified gem to vendor/gems/gem_name-x.x.x
+  rake gems:unpack GEM=bj
+
 * Removed the default .htaccess configuration as there are so many good deployment options now (kept it as an example in README) [DHH]
 
 * config.time_zone accepts TZInfo::Timezone identifiers as well as Rails TimeZone identifiers [Geoff Buesing]
diff --git a/railties/lib/initializer.rb b/railties/lib/initializer.rb
index c60fe3d700..4be7b06f93 100644
--- a/railties/lib/initializer.rb
+++ b/railties/lib/initializer.rb
@@ -7,6 +7,7 @@ require 'railties_path'
 require 'rails/version'
 require 'rails/plugin/locator'
 require 'rails/plugin/loader'
+require 'rails/gem_dependency'
 
 
 RAILS_ENV = (ENV['RAILS_ENV'] || 'development').dup unless defined?(RAILS_ENV)
@@ -77,6 +78,7 @@ module Rails
       
       require_frameworks
       set_autoload_paths
+      add_gem_load_paths
       add_plugin_load_paths
       load_environment
 
@@ -98,8 +100,8 @@ module Rails
 
       add_support_load_paths
 
+      load_gems
       load_plugins
-
       load_application_initializers
 
       # the framework is now fully initialized
@@ -185,6 +187,17 @@ module Rails
       plugin_loader.add_plugin_load_paths
     end
 
+    def add_gem_load_paths
+      unless @configuration.gems.empty?
+        require "rubygems"
+        @configuration.gems.each &:add_load_paths
+      end
+    end
+
+    def load_gems
+      @configuration.gems.each &:load
+    end
+
     # Loads all plugins in <tt>config.plugin_paths</tt>.  <tt>plugin_paths</tt>
     # defaults to <tt>vendor/plugins</tt> but may also be set to a list of
     # paths, such as
@@ -229,7 +242,11 @@ module Rails
 
     def load_observers
       if configuration.frameworks.include?(:active_record)
-        ActiveRecord::Base.instantiate_observers
+        if @configuration.gems.any? { |g| !g.loaded? }
+          puts "Unable to instantiate observers, some gems that this application depends on are missing.  Run 'rake gems:install'"
+        else
+          ActiveRecord::Base.instantiate_observers
+        end
       end
     end
 
@@ -494,6 +511,25 @@ module Rails
     # a sub class would have access to fine grained modification of the loading behavior. See
     # the implementation of Rails::Plugin::Loader for more details.
     attr_accessor :plugin_loader
+
+    # An array of gems that this rails application depends on.  Rails will automatically load
+    # these gems during installation, and allow you to install any missing gems with:
+    #
+    #   rake gems:install
+    #
+    # You can add with the #gem method.
+    attr_accessor :gems
+
+    # Adds a single Gem dependency to the rails application.
+    #
+    #   # gem 'aws-s3', '>= 0.4.0'
+    #   # require 'aws/s3'
+    #   config.gem 'aws-s3', :lib => 'aws/s3', :version => '>= 0.4.0', \
+    #     :source => "http://code.whytheluckystiff.net"
+    #
+    def gem(name, options = {})
+      @gems << Rails::GemDependency.new(name, options)
+    end
     
     # Deprecated options:
     def breakpoint_server(_ = nil)
@@ -529,6 +565,7 @@ module Rails
       self.plugin_locators              = default_plugin_locators
       self.plugin_loader                = default_plugin_loader
       self.database_configuration_file  = default_database_configuration_file
+      self.gems                         = default_gems
 
       for framework in default_frameworks
         self.send("#{framework}=", Rails::OrderedOptions.new)
@@ -712,6 +749,10 @@ module Rails
           :memory_store
         end
       end
+      
+      def default_gems
+        []
+      end
   end
 end
 
diff --git a/railties/lib/rails/gem_dependency.rb b/railties/lib/rails/gem_dependency.rb
new file mode 100644
index 0000000000..ed16464887
--- /dev/null
+++ b/railties/lib/rails/gem_dependency.rb
@@ -0,0 +1,78 @@
+module Rails
+  class GemDependency
+    attr_accessor :name, :requirement, :version, :lib, :source
+
+    def self.unpacked_path
+      @unpacked_path ||= File.join(RAILS_ROOT, 'vendor', 'gems')
+    end
+
+    def initialize(name, options = {})
+      @name     = name.to_s
+      if options[:version]
+        @requirement = Gem::Requirement.create(options[:version])
+        @version     = @requirement.requirements.first.last
+      end
+      @lib      = options[:lib]
+      @source   = options[:source]
+      @loaded   = false
+      @load_paths_added = false
+      @unpack_directory = nil
+    end
+
+    def add_load_paths
+      return if @loaded || @load_paths_added
+      unpacked_paths = Dir[File.join(self.class.unpacked_path, "#{@name}-#{@version || "*"}")]
+      if unpacked_paths.empty?
+        args = [@name]
+        args << @requirement.to_s if @requirement
+        gem *args
+      else
+        $LOAD_PATH << File.join(unpacked_paths.first, 'lib')
+      end
+      @load_paths_added = true
+    rescue Gem::LoadError
+      puts $!.to_s
+    end
+
+    def load
+      return if @load_paths_added == false
+      require(@lib || @name)
+      @loaded = true
+    rescue LoadError
+      puts $!.to_s
+      $!.backtrace.each { |b| puts b }
+    end
+
+    def loaded?
+      @loaded
+    end
+
+    def load_paths_added?
+      @load_paths_added
+    end
+
+    def install
+      Gem::GemRunner.new.run(install_command)
+    end
+
+    def unpack_to(directory)
+      FileUtils.mkdir_p directory
+      Dir.chdir directory do
+        Gem::GemRunner.new.run(unpack_command)
+      end
+    end
+
+    def install_command
+      cmd = %w(install) << @name
+      cmd << "--version" << "#{@requirement.to_s}" if @requirement
+      cmd << "--source"  << @source  if @source
+      cmd
+    end
+    
+    def unpack_command
+      cmd = %w(unpack) << @name
+      cmd << "--version" << "#{@requirement.to_s}" if @requirement
+      cmd
+    end
+  end
+end
\ No newline at end of file
diff --git a/railties/lib/tasks/gems.rake b/railties/lib/tasks/gems.rake
new file mode 100644
index 0000000000..198f6050c3
--- /dev/null
+++ b/railties/lib/tasks/gems.rake
@@ -0,0 +1,31 @@
+desc "List the gems that this rails application depends on"
+task :gems => :environment do
+  Rails.configuration.gems.each do |gem|
+    puts "[#{gem.loaded? ? '*' : ' '}] #{gem.name} #{gem.requirement.to_s}"
+  end
+end
+
+namespace :gems do
+  desc "Installs all required gems for this application."
+  task :install => :environment do
+    require 'rubygems'
+    require 'rubygems/gem_runner'
+    Rails.configuration.gems.each { |gem| gem.install unless gem.loaded? }
+  end
+
+  desc "Unpacks the specified gem into vendor/gems."
+  task :unpack do
+    raise "Specify name of gem in the config.gems array with GEM=" if ENV['GEM'].blank?
+    Rake::Task["environment"].invoke
+    require 'rubygems'
+    require 'rubygems/gem_runner'
+    unless Rails.configuration.gems.select do |gem|
+      if gem.loaded? && gem.name == ENV['GEM']
+        gem.unpack_to(File.join(RAILS_ROOT, 'vendor', 'gems'))
+        true
+      end
+    end.any?
+      puts "No gem named #{ENV['GEM'].inspect} found."
+    end
+  end
+end
\ No newline at end of file
diff --git a/railties/test/gem_dependency_test.rb b/railties/test/gem_dependency_test.rb
new file mode 100644
index 0000000000..887ad53589
--- /dev/null
+++ b/railties/test/gem_dependency_test.rb
@@ -0,0 +1,62 @@
+require 'plugin_test_helper'
+
+uses_mocha "Plugin Tests" do
+  class GemDependencyTest < Test::Unit::TestCase
+    def setup
+      @gem              = Rails::GemDependency.new "hpricot"
+      @gem_with_source  = Rails::GemDependency.new "hpricot", :source => "http://code.whytheluckystiff.net"
+      @gem_with_version = Rails::GemDependency.new "hpricot", :version => "= 0.6"
+      @gem_with_lib     = Rails::GemDependency.new "aws-s3", :lib => "aws/s3" 
+    end
+
+    def test_configuration_adds_gem_dependency
+      config = Rails::Configuration.new
+      config.gem "aws-s3", :lib => "aws/s3", :version => "0.4.0"
+      assert_equal [["install", "aws-s3", "--version", "= 0.4.0"]], config.gems.collect(&:install_command)
+    end
+
+    def test_gem_creates_install_command
+      assert_equal %w(install hpricot), @gem.install_command
+    end
+
+    def test_gem_with_source_creates_install_command
+      assert_equal %w(install hpricot --source http://code.whytheluckystiff.net), @gem_with_source.install_command
+    end
+
+    def test_gem_with_version_creates_install_command
+      assert_equal ["install", "hpricot", "--version", "= 0.6"], @gem_with_version.install_command
+    end
+
+    def test_gem_creates_unpack_command
+      assert_equal %w(unpack hpricot), @gem.unpack_command
+    end
+
+    def test_gem_with_version_unpack_install_command
+      assert_equal ["unpack", "hpricot", "--version", "= 0.6"], @gem_with_version.unpack_command
+    end
+
+    def test_gem_adds_load_paths
+      @gem.expects(:gem).with(@gem.name)
+      @gem.add_load_paths
+    end
+  
+    def test_gem_with_version_adds_load_paths
+      @gem_with_version.expects(:gem).with(@gem_with_version.name, @gem_with_version.requirement.to_s)
+      @gem_with_version.add_load_paths
+    end
+  
+    def test_gem_loading
+      @gem.expects(:gem).with(@gem.name)
+      @gem.expects(:require).with(@gem.name)
+      @gem.add_load_paths
+      @gem.load
+    end
+  
+    def test_gem_with_lib_loading
+      @gem_with_lib.expects(:gem).with(@gem_with_lib.name)
+      @gem_with_lib.expects(:require).with(@gem_with_lib.lib)
+      @gem_with_lib.add_load_paths
+      @gem_with_lib.load
+    end
+  end
+end
\ No newline at end of file