Add cache count metrics to rails cache

CHANGELOG

@@ -51,6 +51,7 @@ v 8.8.0 (unreleased)
   - Add API endpoints for un/subscribing from/to a label. !4051 (Ahmad Sherif)
   - Hide left sidebar on phone screens to give more space for content
   - Redesign navigation for profile and group pages
+  - Add counter metrics for rails cache
 
 v 8.7.5
   - Fix relative links in wiki pages. !4050

lib/gitlab/metrics/subscribers/rails_cache.rb

@@ -6,26 +6,28 @@ module Gitlab
         attach_to :active_support
 
         def cache_read(event)
-          increment(:cache_read_duration, event.duration)
+          increment(:cache_read, event.duration)
         end
 
         def cache_write(event)
-          increment(:cache_write_duration, event.duration)
+          increment(:cache_write, event.duration)
         end
 
         def cache_delete(event)
-          increment(:cache_delete_duration, event.duration)
+          increment(:cache_delete, event.duration)
         end
 
         def cache_exist?(event)
-          increment(:cache_exists_duration, event.duration)
+          increment(:cache_exists, event.duration)
         end
 
         def increment(key, duration)
           return unless current_transaction
 
           current_transaction.increment(:cache_duration, duration)
-          current_transaction.increment(key, duration)
+          current_transaction.increment(:cache_count, 1)
+          current_transaction.increment("#{key}_duration".to_sym, duration)
+          current_transaction.increment("#{key}_count".to_sym, 1)
         end
 
         private

spec/lib/gitlab/metrics/subscribers/rails_cache_spec.rb

@@ -9,7 +9,7 @@ describe Gitlab::Metrics::Subscribers::RailsCache do
   describe '#cache_read' do
     it 'increments the cache_read duration' do
       expect(subscriber).to receive(:increment).
-        with(:cache_read_duration, event.duration)
+        with(:cache_read, event.duration)
 
       subscriber.cache_read(event)
     end
@@ -18,7 +18,7 @@ describe Gitlab::Metrics::Subscribers::RailsCache do
   describe '#cache_write' do
     it 'increments the cache_write duration' do
       expect(subscriber).to receive(:increment).
-        with(:cache_write_duration, event.duration)
+        with(:cache_write, event.duration)
 
       subscriber.cache_write(event)
     end
@@ -27,7 +27,7 @@ describe Gitlab::Metrics::Subscribers::RailsCache do
   describe '#cache_delete' do
     it 'increments the cache_delete duration' do
       expect(subscriber).to receive(:increment).
-        with(:cache_delete_duration, event.duration)
+        with(:cache_delete, event.duration)
 
       subscriber.cache_delete(event)
     end
@@ -36,7 +36,7 @@ describe Gitlab::Metrics::Subscribers::RailsCache do
   describe '#cache_exist?' do
     it 'increments the cache_exists duration' do
       expect(subscriber).to receive(:increment).
-        with(:cache_exists_duration, event.duration)
+        with(:cache_exists, event.duration)
 
       subscriber.cache_exist?(event)
     end
@@ -61,10 +61,16 @@ describe Gitlab::Metrics::Subscribers::RailsCache do
         expect(transaction).to receive(:increment).
           with(:cache_duration, event.duration)
 
+        expect(transaction).to receive(:increment).
+          with(:cache_count, 1)
+
         expect(transaction).to receive(:increment).
           with(:cache_delete_duration, event.duration)
 
-        subscriber.increment(:cache_delete_duration, event.duration)
+        expect(transaction).to receive(:increment).
+          with(:cache_delete_count, 1)
+
+        subscriber.increment(:cache_delete, event.duration)
       end
     end
   end