Merge branch 'sc1-redis-client-sentinel-fix' into 'master'

Apply redis sentinel connection closing patch to RedisClient

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144960



Merged-by: Stan Hu <stanhu@gmail.com>
Approved-by: Sam Figueroa <sfigueroa@gitlab.com>
Approved-by: Stan Hu <stanhu@gmail.com>
Co-authored-by: Sylvester Chin <schin@gitlab.com>

config/initializers/7_redis.rb

@@ -30,6 +30,7 @@
 # this only instruments `RedisClient` used in `Sidekiq.redis`
 RedisClient.register(Gitlab::Instrumentation::RedisClientMiddleware)
 RedisClient.prepend(Gitlab::Patch::RedisClient)
+RedisClient::SentinelConfig.prepend(Gitlab::Patch::RedisClientSentinelConfig)
 
 if Gitlab::Redis::Workhorse.params[:cluster].present?
   raise "Do not configure workhorse with a Redis Cluster as pub/sub commands are not cluster-compatible."

lib/gitlab/patch/redis_client_sentinel_config.rb

+# frozen_string_literal: true
+
+if Gem::Version.new(RedisClient::VERSION) != Gem::Version.new('0.20.0')
+  raise 'New version of redis-client detected, please remove or update this patch'
+end
+
+module Gitlab
+  module Patch
+    module RedisClientSentinelConfig
+      # we manually apply the fix in
+      # https://github.com/redis-rb/redis-client/commit/26d355441f5b455294de887397ed8bea2e2c7275
+      # until a new tag is released
+      def each_sentinel
+        last_error = nil
+        # rubocop:disable Gitlab/ModuleWithInstanceVariables -- Directly references code in redis-client gem
+        @sentinel_configs.dup.each do |sentinel_config|
+          sentinel_client = sentinel_client(sentinel_config)
+          success = true
+          begin
+            yield sentinel_client
+          rescue RedisClient::Error => error
+            last_error = error
+            success = false
+            sleep SENTINEL_DELAY
+          ensure
+            @sentinel_configs.unshift(@sentinel_configs.delete(sentinel_config)) if success
+            # Redis Sentinels may be configured to have a lower maxclients setting than
+            # the Redis nodes. Close the connection to the Sentinel node to avoid using
+            # a connection.
+            sentinel_client.close
+            # rubocop:enable Gitlab/ModuleWithInstanceVariables
+          end
+        end
+      end
+    end
+  end
+end