Merge pull request customink#4 from customink/EasySingletonDelegatorP…

…attern

Simple per-request singleton/delegator for metrics instance in Rails.

CHANGELOG.md

@@ -3,6 +3,12 @@
 
 See this https://keepachangelog.com link for information on how we want this documented formatted.
 
+## v0.5.0
+
+### Added
+
+- Simple singleton/delegator for metrics instance in Rails.
+
 ## v0.4.0
 
 ### Changed

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    aws-embedded-metrics-customink (0.4.0)
+    aws-embedded-metrics-customink (0.5.0)
 
 GEM
   remote: https://rubygems.org/

README.md

@@ -56,6 +56,38 @@ Aws::Embedded::Metrics.logger do |metrics|
 end
 ```
 
+## Using Rails?
+
+And want to instrument metrics deep in your code during the request/response lifecycle? Consider creating a PORO like this `Metrics` example.
+
+```ruby
+class MyMetrics < Aws::Embedded::Metrics::Instance
+end
+```
+
+This object is ready to use as a per-request singleton that acts as a simple delegator to all metrics/logger methods. A great way to hook it up for your application is in ApplicationController.
+
+```ruby
+class ApplicationController < ActionController::Base
+  around_action :embedded_metrics
+  private
+  def embedded_metrics
+    Aws::Embedded::Metrics.logger do |metrics|
+      MyMetrics.instance = MyMetrics.new(metrics)
+      yield
+    end
+  end
+end
+```
+
+Now you can happily instrument your code.
+
+```ruby
+proof, time = MyMetrics.benchmark { @imagebuilder.data }
+MyMetrics.put_metric 'ImageBuilderTime', time, 'Milliseconds'
+MyMetrics.set_property 'ImageId', params[:image_id]
+```
+
 ## Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `bin/test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

lib/aws-embedded-metrics-customink.rb

@@ -6,6 +6,7 @@
 require 'aws-embedded-metrics-customink/sinks'
 require 'aws-embedded-metrics-customink/config'
 require 'aws-embedded-metrics-customink/logger'
+require 'aws-embedded-metrics-customink/instance' if defined?(Rails)
 
 module Aws
   module Embedded

lib/aws-embedded-metrics-customink/instance.rb

@@ -0,0 +1,18 @@
+module Aws
+  module Embedded
+    module Metrics
+      class Instance < SimpleDelegator
+        mattr_accessor :instance
+
+        extend SingleForwardable
+
+        def_delegators :instance,
+                       :flush,
+                       :benchmark,
+                       :put_dimension,
+                       :put_metric,
+                       :set_property
+      end
+    end
+  end
+end

lib/aws-embedded-metrics-customink/version.rb

@@ -1,7 +1,7 @@
 module Aws
   module Embedded
     module Metrics
-      VERSION = '0.4.0'.freeze
+      VERSION = '0.5.0'.freeze
     end
   end
 end