Display logs via ActiveSupport::Notifications.instrument

As of this commit, dm-rails provides the same amount
of log information as ActiveRecord, and it does so via
the same interface. This means that logs show up
just like ActiveRecord's in the console, and the
log level for example can be controlled in the same
way as for ActiveRecord (e.g. via config/environments)

This also means that dm-rails now provides all the
information rails_metrics also displays for ActiveRecord.
Currently, rails_metrics only works when used from
my fork at snusnu/rails_metrics (you have to use
the 'datamapper-compatibility' branch). I'm pretty
confident that these changes get merged upstream
eventually.

dm-rails.gemspec

@@ -9,7 +9,7 @@ Gem::Specification.new do |s|
 
   s.required_rubygems_version = Gem::Requirement.new("> 1.3.1") if s.respond_to? :required_rubygems_version=
   s.authors = ["Martin Gamsjaeger (snusnu)", "Dan Kubb"]
-  s.date = %q{2010-05-23}
+  s.date = %q{2010-05-26}
   s.description = %q{Integrate DataMapper with Rails 3}
   s.email = %q{gamsnjaga@gmail.com}
   s.extra_rdoc_files = [
@@ -33,6 +33,7 @@ Gem::Specification.new do |s|
      "lib/dm-rails/railties/controller_runtime.rb",
      "lib/dm-rails/railties/database.rake",
      "lib/dm-rails/railties/i18n_support.rb",
+     "lib/dm-rails/railties/log_listener.rb",
      "lib/dm-rails/railties/log_subscriber.rb",
      "lib/dm-rails/session_store.rb",
      "lib/dm-rails/setup.rb",

lib/dm-rails/railties/log_listener.rb

@@ -0,0 +1,15 @@
+module LogListener
+  def log(message)
+    ActiveSupport::Notifications.instrument('sql.data_mapper',
+      :name          => 'SQL',
+      :sql           => message.query, # TODO think about changing the key to :query
+      :start         => message.start,
+      :duration      => message.duration,
+      :connection_id => self.object_id
+    )
+    super
+  rescue Exception => e
+    # TODO proper logging
+    puts "[datamapper - ERROR] #{e.class.name}: #{e.message}: #{message.inspect}}"
+  end
+end

lib/dm-rails/railties/log_subscriber.rb

@@ -3,6 +3,11 @@ module Railties
 
     class LogSubscriber < Rails::LogSubscriber
 
+      def initialize
+        super
+        @odd_or_even = false
+      end
+
       def sql(event)
         name = '%s (%.1fms)' % [event.payload[:name], event.duration]
         sql  = event.payload[:sql].squeeze(' ')

lib/dm-rails/setup.rb

@@ -1,6 +1,7 @@
 require 'active_support/core_ext/hash/except'
 
 require 'dm-rails/configuration'
+require 'dm-rails/railties/log_listener'
 require 'dm-rails/railties/benchmarking_mixin'
 
 module Rails
@@ -14,14 +15,26 @@ def self.setup(environment)
       initialize_foreign_keys
     end
 
-    def self.setup_logger(logger)
-      ::DataMapper.logger = logger
-    end
-
     def self.setup_with_instrumentation(name, options)
       puts "[datamapper] Setting up #{name.inspect} repository: '#{options['database']}' on #{options['adapter']}"
       adapter = ::DataMapper.setup(name, options)
       adapter.extend ::DataMapper::Adapters::Benchmarking
+      setup_log_listener(options['adapter'])
+    end
+
+    def self.setup_logger(logger)
+      ::DataMapper.logger = logger
+    end
+
+    def self.setup_log_listener(adapter_name)
+      if Object.const_defined?('DataObjects')
+        DataObjects::Connection.send(:include, LogListener)
+        # FIXME Setting DataMapper::Logger.new($stdout, :off) alone won't work because the #log
+        # method is currently only available in DO and needs an explicit DO Logger instantiated.
+        # We turn the logger :off because ActiveSupport::Notifications handles displaying log messages
+        do_adapter = DataObjects.const_get(adapter_name.classify)
+        do_adapter.logger = DataObjects::Logger.new($stdout, :off)
+      end
     end
 
     def self.initialize_foreign_keys