Merge pull request #40490 from kirs/cache-instrument-store-local

Instrument cache entries from local cache

activesupport/lib/active_support/cache.rb

@@ -324,7 +324,7 @@ module ActiveSupport
 
           entry = nil
           instrument(:read, name, options) do |payload|
-            cached_entry = read_entry(key, **options) unless options[:force]
+            cached_entry = read_entry(key, **options, event: payload) unless options[:force]
             entry = handle_expired_entry(cached_entry, key, options)
             entry = nil if entry && entry.mismatched?(normalize_version(name, options))
             payload[:super_operation] = :fetch if payload
@@ -358,7 +358,7 @@ module ActiveSupport
         version = normalize_version(name, options)
 
         instrument(:read, name, options) do |payload|
-          entry = read_entry(key, **options)
+          entry = read_entry(key, **options, event: payload)
 
           if entry
             if entry.expired?
@@ -390,7 +390,7 @@ module ActiveSupport
         options = merged_options(options)
 
         instrument :read_multi, names, options do |payload|
-          read_multi_entries(names, **options).tap do |results|
+          read_multi_entries(names, **options, event: payload).tap do |results|
             payload[:hits] = results.keys
           end
         end
@@ -500,8 +500,8 @@ module ActiveSupport
       def exist?(name, options = nil)
         options = merged_options(options)
 
-        instrument(:exist?, name) do
-          entry = read_entry(normalize_key(name, options), **options)
+        instrument(:exist?, name) do |payload|
+          entry = read_entry(normalize_key(name, options), **options, event: payload)
           (entry && !entry.expired? && !entry.mismatched?(normalize_version(name, options))) || false
         end
       end

activesupport/lib/active_support/cache/strategy/local_cache.rb

@@ -130,7 +130,13 @@ module ActiveSupport
         private
           def read_entry(key, **options)
             if cache = local_cache
-              cache.fetch_entry(key) { super }
+              hit = true
+              value = cache.fetch_entry(key) do
+                hit = false
+                super
+              end
+              options[:event][:store] = cache.class.name if hit
+              value
             else
               super
             end

activesupport/test/cache/behaviors/local_cache_behavior.rb

@@ -1,6 +1,23 @@
 # frozen_string_literal: true
 
 module LocalCacheBehavior
+  def test_instrumentation_with_local_cache
+    events = with_instrumentation "write" do
+      @cache.write("foo", "bar")
+    end
+    assert_equal @cache.class.name, events[0].payload[:store]
+
+    events = with_instrumentation "read" do
+      @cache.with_local_cache do
+        @cache.read("foo")
+        @cache.read("foo")
+      end
+    end
+
+    expected = [@cache.class.name, "ActiveSupport::Cache::Strategy::LocalCache::LocalStore"]
+    assert_equal expected, events.map { |p| p.payload[:store] }
+  end
+
   def test_local_writes_are_persistent_on_the_remote_cache
     retval = @cache.with_local_cache do
       @cache.write("foo", "bar")