93 lines
1.7 KiB
Ruby
93 lines
1.7 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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class Daemon
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def self.initialize_instance(...)
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raise "#{name} singleton instance already initialized" if @instance
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@instance = new(...)
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Kernel.at_exit(&@instance.method(:stop))
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@instance
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end
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def self.instance(...)
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@instance ||= initialize_instance(...)
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end
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attr_reader :thread
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def thread?
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!thread.nil?
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end
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# Possible options:
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# - synchronous [Boolean] if true, turns `start` into a blocking call
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def initialize(**options)
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@synchronous = options[:synchronous]
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@mutex = Mutex.new
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end
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def enabled?
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true
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end
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def thread_name
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self.class.name.demodulize.underscore
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end
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def start
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return unless enabled?
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@mutex.synchronize do
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break thread if thread?
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if start_working
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@thread = Thread.new do
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Thread.current.name = thread_name
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run_thread
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end
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@thread.join if @synchronous
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@thread
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end
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end
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end
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def stop
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@mutex.synchronize do
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break unless thread?
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stop_working
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if thread
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thread.wakeup if thread.alive?
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begin
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thread.join unless Thread.current == thread
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rescue Exception # rubocop:disable Lint/RescueException
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end
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@thread = nil
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end
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end
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end
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private
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# Executed in lock context before starting thread
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# Needs to return success
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def start_working
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true
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end
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# Executed in separate thread
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def run_thread
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raise NotImplementedError
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end
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# Executed in lock context
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def stop_working
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# no-ops
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end
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end
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end
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