Change object type yielded to ActiveSupport::Subscribers

https://github.com/kickstarter/rack-attack/issues/255

Change the object type from instances of type Rack::Attack::Request to
instances of type Hash. (`req` becomes `request: req`).

README.md

@@ -215,7 +215,8 @@ Rack::Attack.track("special_agent", limit: 6, period: 60) do |req|
 end
 
 # Track it using ActiveSupport::Notification
-ActiveSupport::Notifications.subscribe("rack.attack") do |name, start, finish, request_id, req|
+ActiveSupport::Notifications.subscribe("rack.attack") do |name, start, finish, request_id, payload|
+  req = payload[:request]
   if req.env['rack.attack.matched'] == "special_agent" && req.env['rack.attack.match_type'] == :track
     Rails.logger.info "special_agent: #{req.path}"
     STATSD.increment("special_agent")
@@ -283,8 +284,8 @@ Rack::Attack uses the [ActiveSupport::Notifications](http://api.rubyonrails.org/
 You can subscribe to 'rack.attack' events and log it, graph it, etc:
 
 ```ruby
-ActiveSupport::Notifications.subscribe('rack.attack') do |name, start, finish, request_id, req|
-  puts req.inspect
+ActiveSupport::Notifications.subscribe('rack.attack') do |name, start, finish, request_id, payload|
+  puts payload[:request].inspect
 end
 ```
 

lib/rack/attack.rb

@@ -100,7 +100,7 @@ class Rack::Attack
     end
 
     def instrument(req)
-      notifier.instrument('rack.attack', req) if notifier
+      notifier.instrument('rack.attack', request: req) if notifier
     end
 
     def cache

spec/acceptance/track_spec.rb

@@ -9,9 +9,9 @@ describe "#track" do
     notification_matched = nil
     notification_type = nil
 
-    ActiveSupport::Notifications.subscribe("rack.attack") do |_name, _start, _finish, _id, request|
-      notification_matched = request.env["rack.attack.matched"]
-      notification_type = request.env["rack.attack.match_type"]
+    ActiveSupport::Notifications.subscribe("rack.attack") do |_name, _start, _finish, _id, payload|
+      notification_matched = payload[:request].env["rack.attack.matched"]
+      notification_type = payload[:request].env["rack.attack.match_type"]
     end
 
     get "/", {}, "REMOTE_ADDR" => "5.6.7.8"

spec/acceptance/track_throttle_spec.rb

@@ -12,9 +12,9 @@ describe "#track with throttle-ish options" do
     notification_matched = nil
     notification_type = nil
 
-    ActiveSupport::Notifications.subscribe("rack.attack") do |_name, _start, _finish, _id, request|
-      notification_matched = request.env["rack.attack.matched"]
-      notification_type = request.env["rack.attack.match_type"]
+    ActiveSupport::Notifications.subscribe("rack.attack") do |_name, _start, _finish, _id, payload|
+      notification_matched = payload[:request].env["rack.attack.matched"]
+      notification_type = payload[:request].env["rack.attack.match_type"]
     end
 
     get "/", {}, "REMOTE_ADDR" => "1.2.3.4"

spec/rack_attack_instrumentation_spec.rb

@@ -0,0 +1,31 @@
+# ActiveSupport::Subscribers added in ~> 4.0.2.0
+if ActiveSupport::VERSION::MAJOR > 3
+  require_relative 'spec_helper'
+  require 'active_support/subscriber'
+  class CustomSubscriber < ActiveSupport::Subscriber
+    def rack(event)
+      # Do virtually (but not) nothing.
+      event.inspect
+    end
+  end
+
+  describe 'Rack::Attack.instrument' do
+    before do
+      @period = 60 # Use a long period; failures due to cache key rotation less likely
+      Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new
+      Rack::Attack.throttle('ip/sec', limit: 1, period: @period) { |req| req.ip }
+    end
+
+    describe "with throttling" do
+      before do
+        ActiveSupport::Notifications.stub(:notifier, ActiveSupport::Notifications::Fanout.new) do
+          CustomSubscriber.attach_to("attack")
+          2.times { get '/', {}, 'REMOTE_ADDR' => '1.2.3.4' }
+        end
+      end
+      it 'should instrument without error' do
+        last_response.status.must_equal 429
+      end
+    end
+  end
+end