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Diffstat (limited to 'lib/gitlab/cluster/lifecycle_events.rb')
-rw-r--r-- | lib/gitlab/cluster/lifecycle_events.rb | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/lib/gitlab/cluster/lifecycle_events.rb b/lib/gitlab/cluster/lifecycle_events.rb new file mode 100644 index 00000000000..b05dca409d1 --- /dev/null +++ b/lib/gitlab/cluster/lifecycle_events.rb @@ -0,0 +1,99 @@ +# frozen_string_literal: true + +module Gitlab + module Cluster + # + # LifecycleEvents lets Rails initializers register application startup hooks + # that are sensitive to forking. For example, to defer the creation of + # watchdog threads. This lets us abstract away the Unix process + # lifecycles of Unicorn, Sidekiq, Puma, Puma Cluster, etc. + # + # We have three lifecycle events. + # + # - before_fork (only in forking processes) + # - worker_start + # - before_master_restart (only in forking processes) + # + # Blocks will be executed in the order in which they are registered. + # + class LifecycleEvents + class << self + # + # Hook registration methods (called from initializers) + # + def on_worker_start(&block) + if in_clustered_environment? + # Defer block execution + (@worker_start_hooks ||= []) << block + else + yield + end + end + + def on_before_fork(&block) + return unless in_clustered_environment? + + # Defer block execution + (@before_fork_hooks ||= []) << block + end + + def on_master_restart(&block) + return unless in_clustered_environment? + + # Defer block execution + (@master_restart_hooks ||= []) << block + end + + # + # Lifecycle integration methods (called from unicorn.rb, puma.rb, etc.) + # + def do_worker_start + @worker_start_hooks&.each do |block| + block.call + end + end + + def do_before_fork + @before_fork_hooks&.each do |block| + block.call + end + end + + def do_master_restart + @master_restart_hooks && @master_restart_hooks.each do |block| + block.call + end + end + + # Puma doesn't use singletons (which is good) but + # this means we need to pass through whether the + # puma server is running in single mode or cluster mode + def set_puma_options(options) + @puma_options = options + end + + private + + def in_clustered_environment? + # Sidekiq doesn't fork + return false if Sidekiq.server? + + # Unicorn always forks + return true if defined?(::Unicorn) + + # Puma sometimes forks + return true if in_clustered_puma? + + # Default assumption is that we don't fork + false + end + + def in_clustered_puma? + return false unless defined?(::Puma) + + @puma_options && @puma_options[:workers] && @puma_options[:workers] > 0 + end + end + end + end +end |