gitlab-org--gitlab-foss/lib/gitlab/cluster/lifecycle_events.rb
Andrew Newdigate 1065f8ce7a Add experimental support for Puma
This allows us (and others) to test drive Puma without it affecting all
users. Puma can be enabled by setting the environment variable
"EXPERIMENTAL_PUMA" to a non empty value.
2018-10-25 17:50:15 +01:00

99 lines
2.6 KiB
Ruby

# 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