1 files changed, 54 insertions, 0 deletions
diff --git a/lib/gitlab/usage/service_ping/payload_keys_processor.rb b/lib/gitlab/usage/service_ping/payload_keys_processor.rb
new file mode 100644
index 00000000000..ea2043ffb83
--- /dev/null
+++ b/lib/gitlab/usage/service_ping/payload_keys_processor.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+# Process the UsageData payload to get the keys that have a metric defintion
+# Get the missing keys from the payload
+module Gitlab
+  module Usage
+    module ServicePing
+      class PayloadKeysProcessor
+        attr_reader :old_payload
+
+        def initialize(old_payload)
+          @old_payload = old_payload
+        end
+
+        def key_paths
+          @key_paths ||= payload_keys.to_a.flatten.compact
+        end
+
+        def missing_instrumented_metrics_key_paths
+          @missing_key_paths ||= metrics_with_instrumentation.map(&:key) - key_paths
+        end
+
+        private
+
+        def payload_keys(payload = old_payload, parents = [])
+          return unless payload.is_a?(Hash)
+
+          payload.map do |key, value|
+            if has_metric_definition?(key, parents)
+              parents.dup.append(key).join('.')
+            else
+              payload_keys(value, parents.dup << key) if value.is_a?(Hash)
+            end
+          end
+        end
+
+        def has_metric_definition?(key, parent_keys)
+          key_path = parent_keys.dup.append(key).join('.')
+          metric_definitions.key?(key_path)
+        end
+
+        def metric_definitions
+          ::Gitlab::Usage::MetricDefinition.not_removed
+        end
+
+        def metrics_with_instrumentation
+          ::Gitlab::Usage::MetricDefinition.with_instrumentation_class
+        end
+      end
+    end
+  end
+end
+
+Gitlab::Usage::ServicePing::PayloadKeysProcessor.prepend_mod_with('Gitlab::Usage::ServicePing::PayloadKeysProcessor')