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