Merge pull request #1 from customink/drinks/logger-sink

Refactor sinks to be stateful; Add a logger sink

CHANGELOG.md

@@ -3,6 +3,18 @@
 
 See this http:https://keepachangelog.com link for information on how we want this documented formatted.
 
+## v0.2.0
+
+### Changed
+
+- `Lambda` sink renamed to `Stdout` to reflect its destination rather than its intended use
+- The currently configured sink is now accessed through the `Config` object rather than from the root namespace
+- Improved test coverage
+
+### Added
+
+- A `Logger` sink to emit to a Ruby Logger instance, for logfile output
+
 ## v0.1.0
 
 ### Added

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
  remote: .
  specs:
- aws-embedded-metrics-customink (0.1.0)
+ aws-embedded-metrics-customink (0.2.0)
 
 GEM
  remote: https://rubygems.org/

README.md

@@ -29,14 +29,22 @@ gem 'aws-embedded-metrics-customink'
 ```
 ## Usage
 
-Simple configuration.
+Simple configuration:
 
 ```ruby
 Aws::Embedded::Metrics.configure do |c|
  c.namespace = 'MyApplication'
 end
 ```
 
+Using the `Logger` sink to write to a log file:
+
+```ruby
+Aws::Embedded::Metrics.configure do |c|
+ c.sink = Aws::Embedded::Metrics::Sinks::Logger.new(Rails.logger)
+end
+```
+
 Usage is in a scope block. All metrics are flushed afterward
 
 ```ruby

lib/aws-embedded-metrics-customink.rb

@@ -1,14 +1,18 @@
 require 'json'
 require 'benchmark'
 require 'aws-embedded-metrics-customink/version'
-require 'aws-embedded-metrics-customink/config'
 require 'aws-embedded-metrics-customink/sinks'
+require 'aws-embedded-metrics-customink/config'
 require 'aws-embedded-metrics-customink/logger'
 
 module Aws
  module Embedded
  module Metrics
 
+ def config
+ Config.config
+ end
+
  def configure
  Config.configure { |c| yield(c) }
  end
@@ -23,10 +27,6 @@ def logger
  end
  end
 
- def sink
- @sink ||= Sinks::Lambda.new
- end
-
  extend self
 
  end

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

@@ -3,6 +3,8 @@ module Embedded
  module Metrics
  module Config
 
+ DEFAULT_SINK = Sinks::Stdout
+
  def configure
  yield(config)
  config
@@ -20,7 +22,7 @@ def config
 
  class Configuration
 
- attr_writer :namespace
+ attr_writer :namespace, :sink
 
  def reconfigure
  instance_variables.each { |var| instance_variable_set var, nil }
@@ -30,9 +32,14 @@ def reconfigure
 
  def namespace
  return @namespace if defined?(@namespace)
+
  ENV['AWS_EMF_NAMESPACE'] || 'aws-embedded-metrics'
  end
 
+ def sink
+ @sink ||= DEFAULT_SINK.new
+ end
+
  end
  end
  end

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

@@ -3,8 +3,8 @@ module Embedded
  module Metrics
  class Logger
 
- def initialize(sink = Sinks::Lambda)
- @sink = sink.new
+ def initialize(sink = Config.config.sink)
+ @sink = sink
  @namespace = Config.config.namespace
  @dimensions = []
  @metrics = []
@@ -18,7 +18,7 @@ def metrics
  end
 
  def flush
- Metrics.sink.accept(message) unless empty?
+ @sink.accept(message) unless empty?
  end
 
  def put_dimension(name, value)

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

@@ -1 +1,2 @@
-require 'aws-embedded-metrics-customink/sinks/lambda'
+require 'aws-embedded-metrics-customink/sinks/logger'
+require 'aws-embedded-metrics-customink/sinks/stdout'

lib/aws-embedded-metrics-customink/sinks/logger.rb

@@ -0,0 +1,22 @@
+module Aws
+ module Embedded
+ module Metrics
+ module Sinks
+ class Logger
+
+ attr_reader :logger, :level
+
+ def initialize(logger, level: :info)
+ @logger = logger
+ @level = level.to_sym
+ end
+
+ def accept(message)
+ logger.public_send(level, JSON.dump(message))
+ end
+
+ end
+ end
+ end
+ end
+end

lib/aws-embedded-metrics-customink/sinks/lambda.rb → lib/aws-embedded-metrics-customink/sinks/stdout.rb

@@ -2,7 +2,7 @@ module Aws
  module Embedded
  module Metrics
  module Sinks
- class Lambda
+ class Stdout
 
  def accept(message)
  puts JSON.dump(message)

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

@@ -1,7 +1,7 @@
 module Aws
  module Embedded
  module Metrics
- VERSION = '0.1.0'.freeze
+ VERSION = '0.2.0'.freeze
  end
  end
 end

test/cases/sinks/logger_test.rb

@@ -0,0 +1,22 @@
+require 'logger'
+require 'stringio'
+
+module Sinks
+ class LoggerTest < TestCase
+ let(:logger) { Logger.new(StringIO.new) }
+ let(:level) { :info }
+ let(:msg) { { hello: 'world' } }
+ let(:sink) { Aws::Embedded::Metrics::Sinks::Logger.new(logger, level: level) }
+
+ it 'initializes with an instance of a logger and a log level' do
+ expect(sink).must_be_instance_of Aws::Embedded::Metrics::Sinks::Logger
+ expect(sink.logger).must_equal logger
+ expect(sink.level).must_equal level
+ end
+
+ it '#accept dumps its message as json to the logger at the prescribed log level' do
+ logger.expects(:info).with(JSON.dump(msg)).once
+ sink.accept(msg)
+ end
+ end
+end

test/cases/sinks/stdout_test.rb

@@ -0,0 +1,15 @@
+module Sinks
+ class StdoutTest < TestCase
+ let(:msg) { { hello: 'world' } }
+ let(:sink) { Aws::Embedded::Metrics::Sinks::Stdout.new }
+
+ it 'initializes with no arguments' do
+ expect(sink).must_be_instance_of Aws::Embedded::Metrics::Sinks::Stdout
+ end
+
+ it '#accept dumps its message as json to stdout' do
+ STDOUT.expects(:puts).with(JSON.dump(msg)).once
+ sink.accept(msg)
+ end
+ end
+end

test/test_helper.rb

@@ -8,18 +8,15 @@
 class TestCase < MiniTest::Spec
 
  before do
- reconfigure
- setup_test_sink
+ configure
  end
 
  private
 
- def reconfigure
- Aws::Embedded::Metrics.reconfigure
- end
-
- def setup_test_sink
- Aws::Embedded::Metrics.stubs sink: test_sink
+ def configure
+ Aws::Embedded::Metrics.reconfigure do |c|
+ c.sink = test_sink
+ end
  end
 
  def test_sink