From 257f9abd5606504a1a258aacaabc7963c142dd11 Mon Sep 17 00:00:00 2001 From: Claire Date: Wed, 29 May 2024 10:15:06 +0200 Subject: [PATCH] Fix leaking Elasticsearch connections in Sidekiq processes (#30450) --- lib/mastodon/sidekiq_middleware.rb | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/lib/mastodon/sidekiq_middleware.rb b/lib/mastodon/sidekiq_middleware.rb index 9832e1a27..c6bfa492f 100644 --- a/lib/mastodon/sidekiq_middleware.rb +++ b/lib/mastodon/sidekiq_middleware.rb @@ -8,6 +8,7 @@ class Mastodon::SidekiqMiddleware rescue Mastodon::HostValidationError # Do not retry rescue => e + clean_up_elasticsearch_connections! limit_backtrace_and_raise(e) ensure clean_up_sockets! @@ -25,6 +26,32 @@ class Mastodon::SidekiqMiddleware clean_up_statsd_socket! end + # This is a hack to immediately free up unused Elasticsearch connections. + # + # Indeed, Chewy creates one `Elasticsearch::Client` instance per thread, + # and each such client manages its long-lasting connection to + # Elasticsearch. + # + # As far as I know, neither `chewy`, `elasticsearch-transport` or even + # `faraday` provide a reliable way to immediately close a connection, and + # rely on the underlying object to be garbage-collected instead. + # + # Furthermore, `sidekiq` creates a new thread each time a job throws an + # exception, meaning that each failure will create a new connection, and + # the old one will only be closed on full garbage collection. + def clean_up_elasticsearch_connections! + return unless Chewy.enabled? && Chewy.current[:chewy_client].present? + + Chewy.client.transport.connections.each do |connection| + # NOTE: This bit of code is tailored for the HTTPClient Faraday adapter + connection.connection.app.instance_variable_get(:@client)&.reset_all + end + + Chewy.current.delete(:chewy_client) + rescue + nil + end + def clean_up_redis_socket! RedisConfiguration.pool.checkin if Thread.current[:redis] Thread.current[:redis] = nil