Module: Interlock::Config

Defined in:
lib/interlock/config.rb

Constant Summary collapse

CONFIG_FILE = 
"#{RAILS_ROOT}/config/memcached.yml"

Class Method Summary collapse

Class Method Details

.install_finders ⇒ Object

Configure ActiveRecord#find caching.



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# File 'lib/interlock/config.rb', line 161

def install_finders
  RAILS_DEFAULT_LOGGER.warn "** using interlock finder caches"
  ActiveRecord::Base.send(:include, Interlock::Finders)
end

.install_fragments ⇒ Object

Configure Rails to use the memcached store for fragments, and optionally, sessions.



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# File 'lib/interlock/config.rb', line 138

def install_fragments
  # Memcached fragment caching is mandatory        
  ActionView::Helpers::CacheHelper.class_eval do
    def cache(name = {}, options = nil, &block)
      # Things explode if options does not default to nil
      RAILS_DEFAULT_LOGGER.debug "** fragment #{name} stored via obsolete cache() call"
      @controller.fragment_for(output_buffer, name, options, &block)
    end
  end                
  ActionController::Base.cache_store = CACHE
  
  # Sessions are optional
  if Interlock.config[:sessions]
    # XXX Right now this requires memcache-client to be installed, due to a Rails problem.
    # http://dev.rubyonrails.org/ticket/11290
    ActionController::Base.session_store = :mem_cache_store
    ActionController::CgiRequest::DEFAULT_SESSION_OPTIONS.update 'cache' => CACHE      
  end      
end

.install_memcached ⇒ Object

Configure memcached for this app.



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# File 'lib/interlock/config.rb', line 69

def install_memcached
  Interlock.config[:namespace] << "-#{RAILS_ENV}"
  
  unless defined? Object::CACHE

    # Give people a choice of client, even though I don't like conditional dependencies.
    klass = case Interlock.config[:client]
      when 'memcached'
        begin
          Memcached::Rails
        rescue ArgumentError
          raise ConfigurationError, "'memcached' client requested but not installed. Try 'sudo gem install memcached'."
        end
        
      when 'memcache-client'              
        begin
          if MemCache.constants.include?('SVNURL')
            raise ConfigurationError, "You have the Ruby-MemCache gem installed. Please uninstall Ruby-MemCache, or otherwise guarantee that memcache-client will load instead." 
          end
          MemCache              
        rescue ArgumentError
          raise ConfigurationError, "'memcache-client' client requested but not installed. Try 'sudo gem install memcache-client'."
        end
    end
    
    Object.const_set('CACHE', 
      klass.new(
        Interlock.config[:servers], 
        Interlock.config.slice(*CLIENT_KEYS)
      )
    )

    # Mark that we're the ones who did it.
    class << CACHE
      def installed_by_interlock; true; end
    end
    
  else
    begin
      CACHE.installed_by_interlock
    rescue NoMethodError
      RAILS_DEFAULT_LOGGER.warn "** interlock: Object::CACHE already defined; will not install a new one"
      # Mark that somebody else installed this CACHE.
      class << CACHE
        def installed_by_interlock; false; end
      end
    end
  end
  
  # Add the fragment cache and lock APIs to the cache singleton. This happens no matter
  # who installed the singleton.
  class << CACHE
    include Interlock::Lock
    
    def read(*args)
      get args.first.to_s
    end
    
    def write(name, content, options = {})             
      set(name.to_s, 
        content, 
        options.is_a?(Hash) ? options[:ttl] : Interlock.config[:ttl] )
    end
  end
end

.run! ⇒ Object

Load the configuration file, if available, and then set up the Memcached instance, Rails settings, and CACHE constants. Should be more or less compatible with Cache_fu.



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# File 'lib/interlock/config.rb', line 49

def run!
  if File.exist?(CONFIG_FILE)
    template = ERB.new(File.open(CONFIG_FILE) {|f| f.read})       
    config = YAML.load(template.result(binding))
    config.deep_symbolize_keys!

    Interlock.config.merge!(config[:defaults] || {})
    Interlock.config.merge!(config[RAILS_ENV.to_sym] || {})
  end

  install_memcached
  install_fragments        

  # Always install the finders.
  install_finders if Interlock.config[:with_finders]
end