Add Karafka framework, automatically activating WaterDrop

Author: Drowze

lib/datadog/tracing/contrib/karafka/framework.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module Datadog
+  module Tracing
+    module Contrib
+      module Karafka
+        # Karafka framework code, used to essentially:
+        # - handle configuration entries which are specific to Datadog tracing
+        # - instrument parts of the framework when needed
+        module Framework
+          def self.setup
+            Datadog.configure do |datadog_config|
+              karafka_config = datadog_config.tracing[:karafka]
+              activate_waterdrop!(datadog_config, karafka_config)
+            end
+          end
+
+          # Apply relevant configuration from Karafka to WaterDrop
+          def self.activate_waterdrop!(datadog_config, karafka_config)
+            datadog_config.tracing.instrument(
+              :waterdrop,
+              service_name: karafka_config[:service_name],
+              distributed_tracing: karafka_config[:distributed_tracing],
+            )
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/tracing/contrib/karafka/patcher.rb

@@ -63,6 +63,9 @@ def patch
 
             ::Karafka::Instrumentation::Monitor.prepend(Monitor)
             ::Karafka::Messages::Messages.prepend(MessagesPatch)
+
+            # Activate tracing on components related to Karafka (e.g. WaterDrop)
+            Framework.setup
           end
         end
       end