Initial version of gemified mongo instrumentation, taken from the ini…

…tial experimental version here: http://tomafro.net/2011/02/experimental-mongo-instrumentation

.gitignore

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+*.gem
+.bundle
+Gemfile.lock
+pkg/*

Gemfile

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+source "http://rubygems.org"
+
+# Specify your gem's dependencies in mongo-rails-instrumentation.gemspec
+gemspec

README

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+Mongo Rails 3 Instrumentation
+=============================
+
+Records how long your rails app spends in Mongo, and outputs it to the log, i.e.:
+
+    Completed 200 OK in 1535ms (Views: 623.3ms | Mongo: 848.2ms)
+
+To use, just add the gem to your Gemfile and restart your app:
+
+    gem 'mongo-rails-instrumentation', '~>0.1'
+
+This gem's home is on github at https://github.com/freerange/mongo-rails-instrumentation, so please add comments, suggestions and improvements there.

Rakefile

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+require 'bundler'
+Bundler::GemHelper.install_tasks

lib/mongo-rails-instrumentation.rb

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+require 'mongo/rails/instrumentation/railtie'

lib/mongo/rails/instrumentation.rb

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+module Mongo
+  module Rails
+    module Instrumentation
+      autoload :Version, 'mongo/rails/instrumentation/version'
+      autoload :Railtie, 'mongo/rails/instrumentation/railtie'
+      autoload :LogSubscriber, 'mongo/rails/instrumentation/log_subscriber'
+      autoload :ControllerRuntime, 'mongo/rails/instrumentation/controller_runtime'
+    end
+  end
+end

lib/mongo/rails/instrumentation/controller_runtime.rb

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+require 'mongo/rails/instrumentation'
+
+module Mongo::Rails::Instrumentation
+  module ControllerRuntime
+    extend ActiveSupport::Concern
+
+    protected
+
+    attr_internal :mongo_runtime
+
+    def cleanup_view_runtime
+      mongo_rt_before_render = LogSubscriber.reset_runtime
+      runtime = super
+      mongo_rt_after_render = LogSubscriber.reset_runtime
+      self.mongo_runtime = mongo_rt_before_render + mongo_rt_after_render
+      runtime - mongo_rt_after_render
+    end
+
+    def append_info_to_payload(payload)
+      super
+      payload[:mongo_runtime] = mongo_runtime
+    end
+
+    module ClassMethods
+      def log_process_action(payload)
+        messages, mongo_runtime = super, payload[:mongo_runtime]
+        messages << ("Mongo: %.1fms" % mongo_runtime.to_f) if mongo_runtime
+        messages
+      end
+    end
+  end
+end

lib/mongo/rails/instrumentation/log_subscriber.rb

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+require 'mongo/rails/instrumentation'
+
+class Mongo::Rails::Instrumentation::LogSubscriber < ActiveSupport::LogSubscriber
+  def self.runtime=(value)
+    Thread.current["mongo_mongo_runtime"] = value
+  end
+
+  def self.runtime
+    Thread.current["mongo_mongo_runtime"] ||= 0
+  end
+
+  def self.reset_runtime
+    rt, self.runtime = runtime, 0
+    rt
+  end
+
+  def mongo(event)
+    self.class.runtime += event.duration
+  end
+end

lib/mongo/rails/instrumentation/railtie.rb

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+require 'mongo/rails/instrumentation'
+
+module Mongo::Rails::Instrumentation
+  class Railtie < Rails::Railtie
+    initializer "mongo.rails.instrumentation" do |app|
+      instrument Mongo::Connection, [
+        :send_message,
+        :send_message_with_safe_check,
+        :receive_message
+      ]
+
+      ActiveSupport.on_load(:action_controller) do
+        include ControllerRuntime
+      end
+
+      LogSubscriber.attach_to :mongo
+    end
+
+    def instrument(clazz, methods)
+      clazz.module_eval do
+        methods.each do |m|
+          class_eval %{def #{m}_with_instrumentation(*args, &block)
+            ActiveSupport::Notifications.instrumenter.instrument "mongo.mongo", :name => "#{m}" do
+              #{m}_without_instrumentation(*args, &block)
+            end
+          end
+          }
+
+          alias_method_chain m, :instrumentation
+        end
+      end
+    end
+  end
+end

lib/mongo/rails/instrumentation/version.rb

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+module Mongo
+  module Rails
+    module Instrumentation
+      VERSION = "0.1.0"
+    end
+  end
+end

mongo-rails-instrumentation.gemspec

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+# -*- encoding: utf-8 -*-
+$:.push File.expand_path("../lib", __FILE__)
+require "mongo/rails/instrumentation/version"
+
+Gem::Specification.new do |s|
+  s.name        = "mongo-rails-instrumentation"
+  s.version     = Mongo::Rails::Instrumentation::VERSION
+  s.platform    = Gem::Platform::RUBY
+  s.authors     = ["Tom Ward"]
+  s.email       = ["tom@popdog.net"]
+  s.homepage    = "http://tomafro.net"
+  s.summary     = %q{Records time spent in mongo and adds to request logs}
+  s.description = %q{Records time spent in mongo and adds to request logs}
+
+  s.files         = `git ls-files`.split("\n")
+  s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
+  s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
+  s.require_paths = ["lib"]
+
+  s.add_dependency 'rails', '~>3.0.0'
+end