Create a stand-alone patcher for rack

lib/ddtrace/contrib/rack/middlewares.rb

@@ -13,16 +13,6 @@ module Rack
       # application. If request tags are not set by the app, they will be set using
       # information available at the Rack level.
       class TraceMiddleware
-        include Base
-        register_as :rack
-
-        option :tracer, default: Datadog.tracer
-        option :service_name, default: 'rack', depends_on: [:tracer] do |value|
-          get_option(:tracer).set_service_info(value, 'rack', Ext::AppTypes::WEB)
-          value
-        end
-        option :distributed_tracing, default: false
-
         def initialize(app, options = {})
           # update options with our configuration, unless it's already available
           [:tracer, :service_name, :distributed_tracing].each do |k|

lib/ddtrace/contrib/rack/patcher.rb

@@ -0,0 +1,21 @@
+module Datadog
+  module Contrib
+    module Rack
+      module Patcher
+        include Base
+        register_as :rack
+
+        option :tracer, default: Datadog.tracer
+        option :distributed_tracing, default: false
+        option :service_name, default: 'rack', depends_on: [:tracer] do |value|
+          get_option(:tracer).set_service_info(value, 'rack', Ext::AppTypes::WEB)
+          value
+        end
+
+        def self.patch
+          require_relative 'middlewares'
+        end
+      end
+    end
+  end
+end

lib/ddtrace/monkey.rb

@@ -4,6 +4,7 @@
 # because patchers do not include any 3rd party module nor even our
 # patching code, which is required on demand, when patching.
 require 'ddtrace/contrib/base'
+require 'ddtrace/contrib/rack/patcher'
 require 'ddtrace/contrib/rails/patcher'
 require 'ddtrace/contrib/active_record/patcher'
 require 'ddtrace/contrib/elasticsearch/patcher'