1 files changed, 22 insertions, 12 deletions

diff --git a/lib/gitlab/metrics/subscribers/rails_cache.rb b/lib/gitlab/metrics/subscribers/rails_cache.rb
index b4e9e85a012..e2cdd6c5358 100644
--- a/lib/gitlab/metrics/subscribers/rails_cache.rb
+++ b/lib/gitlab/metrics/subscribers/rails_cache.rb
@@ -13,7 +13,7 @@ module Gitlab
 
           return unless current_transaction
 
-          labels = { store: event.payload[:store].split('::').last }
+          labels = { store: extract_store_name(event) }
           current_transaction.observe(:gitlab_cache_read_multikey_count, event.payload[:key].size, labels) do
             buckets [10, 50, 100, 1000]
             docstring 'Number of keys for mget in read_multi/fetch_multi'
@@ -26,11 +26,7 @@ module Gitlab
           return unless current_transaction
           return if event.payload[:super_operation] == :fetch
 
-          unless event.payload[:hit]
-            current_transaction.increment(:gitlab_cache_misses_total, 1) do
-              docstring 'Cache read miss'
-            end
-          end
+          track_cache_miss(event) unless event.payload[:hit]
         end
 
         def cache_write(event)
@@ -48,23 +44,23 @@ module Gitlab
         def cache_fetch_hit(event)
           return unless current_transaction
 
-          current_transaction.increment(:gitlab_transaction_cache_read_hit_count_total, 1)
+          labels = { store: extract_store_name(event) }
+          current_transaction.increment(:gitlab_transaction_cache_read_hit_count_total, 1, labels)
         end
 
         def cache_generate(event)
           return unless current_transaction
 
-          current_transaction.increment(:gitlab_cache_misses_total, 1) do
-            docstring 'Cache read miss'
-          end
+          track_cache_miss(event)
 
-          current_transaction.increment(:gitlab_transaction_cache_read_miss_count_total, 1)
+          labels = { store: extract_store_name(event) }
+          current_transaction.increment(:gitlab_transaction_cache_read_miss_count_total, 1, labels)
         end
 
         def observe(key, event)
           return unless current_transaction
 
-          labels = { operation: key, store: event.payload[:store].split('::').last }
+          labels = { operation: key, store: extract_store_name(event) }
 
           current_transaction.increment(:gitlab_cache_operations_total, 1, labels) do
             docstring 'Cache operations'
@@ -76,6 +72,20 @@ module Gitlab
 
         private
 
+        def track_cache_miss(event)
+          # avoid passing in labels to ensure metric has consistent set of labels
+          labels = { store: extract_store_name(event) }
+
+          current_transaction.increment(:gitlab_cache_misses_total, 1, labels) do
+            docstring 'Cache read miss'
+          end
+        end
+
+        def extract_store_name(event)
+          # see payload documentation in https://guides.rubyonrails.org/active_support_instrumentation.html#active-support
+          event.payload[:store].to_s.split('::').last
+        end
+
         def current_transaction
           ::Gitlab::Metrics::WebTransaction.current
         end