Add latest changes from gitlab-org/gitlab@master

2 files changed, 76 insertions, 3 deletions

diff --git a/lib/gitlab/cache/client.rb b/lib/gitlab/cache/client.rb
new file mode 100644
index 00000000000..ac710ee0adf
--- /dev/null
+++ b/lib/gitlab/cache/client.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Cache
+    # It replaces Rails.cache with metrics support
+    class Client
+      DEFAULT_BACKING_RESOURCE = :unknown
+
+      # Build Cache client with the metadata support
+      #
+      # @param cache_identifier [String] defines the location of the cache definition
+      #   Example: "ProtectedBranches::CacheService#fetch"
+      # @param feature_category [Symbol] name of the feature category (from config/feature_categories.yml)
+      # @param caller_id [String] caller id from labkit context
+      # @param backing_resource [Symbol] most affected resource by cache generation (full list: VALID_BACKING_RESOURCES)
+      # @return [Gitlab::Cache::Client]
+      def self.build_with_metadata(
+        cache_identifier:,
+        feature_category:,
+        caller_id: Gitlab::ApplicationContext.current_context_attribute(:caller_id),
+        backing_resource: DEFAULT_BACKING_RESOURCE
+      )
+        new(Metadata.new(
+          caller_id: caller_id,
+          cache_identifier: cache_identifier,
+          feature_category: feature_category,
+          backing_resource: backing_resource
+        ))
+      end
+
+      def initialize(metadata, backend: Rails.cache)
+        @metadata = metadata
+        @metrics = Metrics.new(metadata)
+        @backend = backend
+      end
+
+      def read(name)
+        read_result = backend.read(name)
+
+        if read_result.nil?
+          metrics.increment_cache_miss
+        else
+          metrics.increment_cache_hit
+        end
+
+        read_result
+      end
+
+      def fetch(name, options = nil, &block)
+        read_result = read(name)
+
+        return read_result unless block || read_result
+
+        backend.fetch(name, options) do
+          metrics.observe_cache_generation(&block)
+        end
+      end
+
+      delegate :write, :exist?, :delete, to: :backend
+
+      attr_reader :metadata, :metrics
+
+      private
+
+      attr_reader :backend
+    end
+  end
+end
diff --git a/lib/gitlab/cache/metadata.rb b/lib/gitlab/cache/metadata.rb
index d6c89b5b2c3..224f215ef82 100644
--- a/lib/gitlab/cache/metadata.rb
+++ b/lib/gitlab/cache/metadata.rb
@@ -5,13 +5,18 @@ module Gitlab
     # Value object for cache metadata
     class Metadata
       VALID_BACKING_RESOURCES = [:cpu, :database, :gitaly, :memory, :unknown].freeze
-      DEFAULT_BACKING_RESOURCE = :unknown
 
+      # @param cache_identifier [String] defines the location of the cache definition
+      #   Example: "ProtectedBranches::CacheService#fetch"
+      # @param feature_category [Symbol] name of the feature category (from config/feature_categories.yml)
+      # @param caller_id [String] caller id from labkit context
+      # @param backing_resource [Symbol] most affected resource by cache generation (full list: VALID_BACKING_RESOURCES)
+      # @return [Gitlab::Cache::Metadata]
       def initialize(
         cache_identifier:,
         feature_category:,
         caller_id: Gitlab::ApplicationContext.current_context_attribute(:caller_id),
-        backing_resource: DEFAULT_BACKING_RESOURCE
+        backing_resource: Client::DEFAULT_BACKING_RESOURCE
       )
         @cache_identifier = cache_identifier
         @feature_category = Gitlab::FeatureCategories.default.get!(feature_category)
@@ -28,7 +33,7 @@ module Gitlab
 
         raise "Unknown backing resource: #{resource}" if Gitlab.dev_or_test_env?
 
-        DEFAULT_BACKING_RESOURCE
+        Client::DEFAULT_BACKING_RESOURCE
       end
     end
   end