Merge branch 'sc1-rm-db-loadbalancing-multistore' into 'master'

Remove MultiStore in Gitlab::Redis::DbLoadBalancing

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/137830



Merged-by: Halil Coban <hcoban@gitlab.com>
Reviewed-by: Halil Coban <hcoban@gitlab.com>
Co-authored-by: Sylvester Chin <schin@gitlab.com>

config/feature_flags/development/use_primary_and_secondary_stores_for_db_load_balancing.yml

----
-name: use_primary_and_secondary_stores_for_db_load_balancing
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/111269
-rollout_issue_url:
-milestone: '15.9'
-type: development
-group: group::scalability
-default_enabled: false

config/feature_flags/development/use_primary_store_as_default_for_db_load_balancing.yml

----
-name: use_primary_store_as_default_for_db_load_balancing
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/111269
-rollout_issue_url:
-milestone: '15.9'
-type: development
-group: group::scalability
-default_enabled: false

lib/gitlab/redis/db_load_balancing.rb

@@ -8,15 +8,6 @@ class << self
         def config_fallback
           SharedState
         end
-
-        private
-
-        def redis
-          primary_store = ::Redis.new(params)
-          secondary_store = ::Redis.new(config_fallback.params)
-
-          MultiStore.new(primary_store, secondary_store, store_name)
-        end
       end
     end
   end

spec/lib/gitlab/redis/db_load_balancing_spec.rb

@@ -5,40 +5,4 @@
 RSpec.describe Gitlab::Redis::DbLoadBalancing, feature_category: :scalability do
   include_examples "redis_new_instance_shared_examples", 'db_load_balancing', Gitlab::Redis::SharedState
   include_examples "redis_shared_examples"
-
-  describe '#pool' do
-    let(:config_new_format_host) { "spec/fixtures/config/redis_new_format_host.yml" }
-    let(:config_new_format_socket) { "spec/fixtures/config/redis_new_format_socket.yml" }
-
-    subject { described_class.pool }
-
-    before do
-      allow(described_class).to receive(:config_file_name).and_return(config_new_format_host)
-
-      # Override rails root to avoid having our fixtures overwritten by `redis.yml` if it exists
-      allow(Gitlab::Redis::SharedState).to receive(:rails_root).and_return(mktmpdir)
-      allow(Gitlab::Redis::SharedState).to receive(:config_file_name).and_return(config_new_format_socket)
-    end
-
-    around do |example|
-      clear_pool
-      example.run
-    ensure
-      clear_pool
-    end
-
-    it 'instantiates an instance of MultiStore' do
-      subject.with do |redis_instance|
-        expect(redis_instance).to be_instance_of(::Gitlab::Redis::MultiStore)
-
-        expect(redis_instance.primary_store.connection[:id]).to eq("redis://test-host:6379/99")
-        expect(redis_instance.secondary_store.connection[:id]).to eq("unix:///path/to/redis.sock/0")
-
-        expect(redis_instance.instance_name).to eq('DbLoadBalancing')
-      end
-    end
-
-    it_behaves_like 'multi store feature flags', :use_primary_and_secondary_stores_for_db_load_balancing,
-      :use_primary_store_as_default_for_db_load_balancing
-  end
 end

spec/support/shared_examples/lib/gitlab/redis/multi_store_feature_flags_shared_examples.rb

-# frozen_string_literal: true
-
-RSpec.shared_examples 'multi store feature flags' do |use_primary_and_secondary_stores, use_primary_store_as_default|
-  context "with feature flag :#{use_primary_and_secondary_stores} is enabled" do
-    before do
-      stub_feature_flags(use_primary_and_secondary_stores => true)
-    end
-
-    it 'multi store is enabled' do
-      subject.with do |redis_instance|
-        expect(redis_instance.use_primary_and_secondary_stores?).to be true
-      end
-    end
-  end
-
-  context "with feature flag :#{use_primary_and_secondary_stores} is disabled" do
-    before do
-      stub_feature_flags(use_primary_and_secondary_stores => false)
-    end
-
-    it 'multi store is disabled' do
-      subject.with do |redis_instance|
-        expect(redis_instance.use_primary_and_secondary_stores?).to be false
-      end
-    end
-  end
-
-  context "with feature flag :#{use_primary_store_as_default} is enabled" do
-    before do
-      stub_feature_flags(use_primary_store_as_default => true)
-    end
-
-    it 'primary store is enabled' do
-      subject.with do |redis_instance|
-        expect(redis_instance.use_primary_store_as_default?).to be true
-      end
-    end
-  end
-
-  context "with feature flag :#{use_primary_store_as_default} is disabled" do
-    before do
-      stub_feature_flags(use_primary_store_as_default => false)
-    end
-
-    it 'primary store is disabled' do
-      subject.with do |redis_instance|
-        expect(redis_instance.use_primary_store_as_default?).to be false
-      end
-    end
-  end
-end