1 files changed, 72 insertions, 3 deletions

diff --git a/lib/gitlab/cache/helpers.rb b/lib/gitlab/cache/helpers.rb
index 7b11d6bc9ff..48b6ca59367 100644
--- a/lib/gitlab/cache/helpers.rb
+++ b/lib/gitlab/cache/helpers.rb
@@ -57,9 +57,19 @@ module Gitlab
       # @param expires_in [ActiveSupport::Duration, Integer] an expiry time for the cache entry
       # @return [String]
       def cached_object(object, presenter:, presenter_args:, context:, expires_in:)
-        cache.fetch(contextual_cache_key(presenter, object, context), expires_in: expires_in) do
-          Gitlab::Json.dump(presenter.represent(object, **presenter_args).as_json)
+        misses = 0
+
+        json = cache.fetch(contextual_cache_key(presenter, object, context), expires_in: expires_in) do
+          time_action(render_type: :object) do
+            misses += 1
+
+            Gitlab::Json.dump(presenter.represent(object, **presenter_args).as_json)
+          end
         end
+
+        increment_cache_metric(render_type: :object, total_count: 1, miss_count: misses)
+
+        json
       end
 
       # Used for fetching or rendering multiple objects
@@ -71,10 +81,18 @@ module Gitlab
       # @param expires_in [ActiveSupport::Duration, Integer] an expiry time for the cache entry
       # @return [Array<String>]
       def cached_collection(collection, presenter:, presenter_args:, context:, expires_in:)
+        misses = 0
+
         json = fetch_multi(presenter, collection, context: context, expires_in: expires_in) do |obj|
-          Gitlab::Json.dump(presenter.represent(obj, **presenter_args).as_json)
+          time_action(render_type: :collection) do
+            misses += 1
+
+            Gitlab::Json.dump(presenter.represent(obj, **presenter_args).as_json)
+          end
         end
 
+        increment_cache_metric(render_type: :collection, total_count: collection.length, miss_count: misses)
+
         json.values
       end
 
@@ -106,6 +124,57 @@ module Gitlab
           contextual_cache_key(presenter, object, context)
         end
       end
+
+      def increment_cache_metric(render_type:, total_count:, miss_count:)
+        return unless Feature.enabled?(:add_timing_to_certain_cache_actions)
+        return unless caller_id
+
+        metric_name = :cached_object_operations_total
+        hit_count = total_count - miss_count
+
+        current_transaction&.increment(
+          metric_name,
+          hit_count,
+          { caller_id: caller_id, render_type: render_type, cache_hit: true }
+        )
+
+        current_transaction&.increment(
+          metric_name,
+          miss_count,
+          { caller_id: caller_id, render_type: render_type, cache_hit: false }
+        )
+      end
+
+      def time_action(render_type:, &block)
+        if Feature.enabled?(:add_timing_to_certain_cache_actions)
+          real_start = Gitlab::Metrics::System.monotonic_time
+
+          presented_object = yield
+
+          real_duration_histogram(render_type).observe({}, Gitlab::Metrics::System.monotonic_time - real_start)
+
+          presented_object
+        else
+          yield
+        end
+      end
+
+      def real_duration_histogram(render_type)
+        Gitlab::Metrics.histogram(
+          :gitlab_presentable_object_cacheless_render_real_duration_seconds,
+          'Duration of generating presentable objects to be cached in real time',
+          { caller_id: caller_id, render_type: render_type },
+          [0.1, 0.5, 1, 2]
+        )
+      end
+
+      def current_transaction
+        @current_transaction ||= ::Gitlab::Metrics::WebTransaction.current
+      end
+
+      def caller_id
+        @caller_id ||= Gitlab::ApplicationContext.current_context_attribute(:caller_id)
+      end
     end
   end
 end