mirror of
https://github.com/puma/puma.git
synced 2022-11-09 13:48:40 -05:00
648 lines
16 KiB
Ruby
648 lines
16 KiB
Ruby
# frozen_string_literal: true
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require 'puma/runner'
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require 'puma/util'
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require 'puma/plugin'
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require 'time'
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require 'json'
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module Puma
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# This class is instantiated by the `Puma::Launcher` and used
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# to boot and serve a Ruby application when puma "workers" are needed
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# i.e. when using multi-processes. For example `$ puma -w 5`
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#
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# At the core of this class is running an instance of `Puma::Server` which
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# gets created via the `start_server` method from the `Puma::Runner` class
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# that this inherits from.
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#
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# An instance of this class will spawn the number of processes passed in
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# via the `spawn_workers` method call. Each worker will have it's own
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# instance of a `Puma::Server`.
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class Cluster < Runner
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def initialize(cli, events)
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super cli, events
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@phase = 0
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@workers = []
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@next_check = Time.now
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@phased_restart = false
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end
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def stop_workers
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log "- Gracefully shutting down workers..."
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@workers.each { |x| x.term }
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begin
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loop do
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wait_workers
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break if @workers.reject {|w| w.pid.nil?}.empty?
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sleep 0.2
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end
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rescue Interrupt
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log "! Cancelled waiting for workers"
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end
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end
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def start_phased_restart
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@phase += 1
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log "- Starting phased worker restart, phase: #{@phase}"
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# Be sure to change the directory again before loading
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# the app. This way we can pick up new code.
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dir = @launcher.restart_dir
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log "+ Changing to #{dir}"
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Dir.chdir dir
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end
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def redirect_io
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super
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@workers.each { |x| x.hup }
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end
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class Worker
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def initialize(idx, pid, phase, options)
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@index = idx
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@pid = pid
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@phase = phase
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@stage = :started
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@signal = "TERM"
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@options = options
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@first_term_sent = nil
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@started_at = Time.now
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@last_checkin = Time.now
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@last_status = {}
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@term = false
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end
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attr_reader :index, :pid, :phase, :signal, :last_checkin, :last_status, :started_at
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attr_writer :pid, :phase
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def booted?
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@stage == :booted
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end
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def boot!
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@last_checkin = Time.now
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@stage = :booted
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end
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def term?
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@term
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end
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def ping!(status)
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@last_checkin = Time.now
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@last_status = JSON.parse(status, symbolize_names: true)
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end
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def ping_timeout
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@last_checkin +
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(booted? ?
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@options[:worker_timeout] :
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@options[:worker_boot_timeout]
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)
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end
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def term
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begin
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if @first_term_sent && (Time.now - @first_term_sent) > @options[:worker_shutdown_timeout]
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@signal = "KILL"
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else
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@term ||= true
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@first_term_sent ||= Time.now
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end
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Process.kill @signal, @pid if @pid
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rescue Errno::ESRCH
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end
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end
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def kill
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@signal = 'KILL'
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term
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end
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def hup
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Process.kill "HUP", @pid
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rescue Errno::ESRCH
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end
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end
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def spawn_workers
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diff = @options[:workers] - @workers.size
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return if diff < 1
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master = Process.pid
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if @options[:fork_worker]
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@fork_writer << "-1\n"
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end
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diff.times do
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idx = next_worker_index
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if @options[:fork_worker] && idx != 0
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@fork_writer << "#{idx}\n"
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pid = nil
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else
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pid = spawn_worker(idx, master)
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end
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debug "Spawned worker: #{pid}"
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@workers << Worker.new(idx, pid, @phase, @options)
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end
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if @options[:fork_worker] &&
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@workers.all? {|x| x.phase == @phase}
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@fork_writer << "0\n"
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end
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end
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def spawn_worker(idx, master)
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@launcher.config.run_hooks :before_worker_fork, idx, @launcher.events
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pid = fork { worker(idx, master) }
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if !pid
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log "! Complete inability to spawn new workers detected"
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log "! Seppuku is the only choice."
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exit! 1
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end
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@launcher.config.run_hooks :after_worker_fork, idx, @launcher.events
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pid
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end
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def cull_workers
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diff = @workers.size - @options[:workers]
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return if diff < 1
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debug "Culling #{diff.inspect} workers"
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workers_to_cull = @workers[-diff,diff]
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debug "Workers to cull: #{workers_to_cull.inspect}"
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workers_to_cull.each do |worker|
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log "- Worker #{worker.index} (pid: #{worker.pid}) terminating"
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worker.term
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end
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end
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def next_worker_index
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all_positions = 0...@options[:workers]
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occupied_positions = @workers.map { |w| w.index }
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available_positions = all_positions.to_a - occupied_positions
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available_positions.first
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end
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def all_workers_booted?
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@workers.count { |w| !w.booted? } == 0
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end
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def check_workers
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return if @next_check >= Time.now
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@next_check = Time.now + Const::WORKER_CHECK_INTERVAL
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timeout_workers
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wait_workers
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cull_workers
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spawn_workers
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if all_workers_booted?
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# If we're running at proper capacity, check to see if
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# we need to phase any workers out (which will restart
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# in the right phase).
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#
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w = @workers.find { |x| x.phase != @phase }
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if w
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log "- Stopping #{w.pid} for phased upgrade..."
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unless w.term?
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w.term
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log "- #{w.signal} sent to #{w.pid}..."
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end
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end
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end
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@next_check = [
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@workers.reject(&:term?).map(&:ping_timeout).min,
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@next_check
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].compact.min
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end
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def wakeup!
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return unless @wakeup
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begin
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@wakeup.write "!" unless @wakeup.closed?
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rescue SystemCallError, IOError
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Thread.current.purge_interrupt_queue if Thread.current.respond_to? :purge_interrupt_queue
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end
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end
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def worker(index, master)
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title = "puma: cluster worker #{index}: #{master}"
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title += " [#{@options[:tag]}]" if @options[:tag] && !@options[:tag].empty?
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$0 = title
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Signal.trap "SIGINT", "IGNORE"
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fork_worker = @options[:fork_worker] && index == 0
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@workers = []
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if !@options[:fork_worker] || fork_worker
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@master_read.close
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@suicide_pipe.close
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@fork_writer.close
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end
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Thread.new do
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Puma.set_thread_name "worker check pipe"
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IO.select [@check_pipe]
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log "! Detected parent died, dying"
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exit! 1
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end
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# If we're not running under a Bundler context, then
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# report the info about the context we will be using
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if !ENV['BUNDLE_GEMFILE']
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if File.exist?("Gemfile")
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log "+ Gemfile in context: #{File.expand_path("Gemfile")}"
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elsif File.exist?("gems.rb")
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log "+ Gemfile in context: #{File.expand_path("gems.rb")}"
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end
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end
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# Invoke any worker boot hooks so they can get
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# things in shape before booting the app.
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@launcher.config.run_hooks :before_worker_boot, index, @launcher.events
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server = @server ||= start_server
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restart_server = Queue.new << true << false
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if fork_worker
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restart_server.clear
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Signal.trap "SIGCHLD" do
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Process.wait(-1, Process::WNOHANG) rescue nil
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wakeup!
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end
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Thread.new do
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Puma.set_thread_name "worker fork pipe"
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while (idx = @fork_pipe.gets)
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idx = idx.to_i
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if idx == -1 # stop server
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if restart_server.length > 0
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restart_server.clear
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server.begin_restart(true)
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@launcher.config.run_hooks :before_refork, nil, @launcher.events
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GC.compact if GC.respond_to?(:compact)
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end
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elsif idx == 0 # restart server
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restart_server << true << false
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else # fork worker
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pid = spawn_worker(idx, master)
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@worker_write << "f#{pid}:#{idx}\n" rescue nil
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end
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end
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end
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end
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Signal.trap "SIGTERM" do
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@worker_write << "e#{Process.pid}\n" rescue nil
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server.stop
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restart_server << false
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end
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begin
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@worker_write << "b#{Process.pid}:#{index}\n"
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rescue SystemCallError, IOError
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Thread.current.purge_interrupt_queue if Thread.current.respond_to? :purge_interrupt_queue
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STDERR.puts "Master seems to have exited, exiting."
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return
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end
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Thread.new(@worker_write) do |io|
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Puma.set_thread_name "stat payload"
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while true
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sleep Const::WORKER_CHECK_INTERVAL
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begin
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io << "p#{Process.pid}#{server.stats.to_json}\n"
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rescue IOError
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Thread.current.purge_interrupt_queue if Thread.current.respond_to? :purge_interrupt_queue
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break
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end
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end
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end
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server.run.join while restart_server.pop
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# Invoke any worker shutdown hooks so they can prevent the worker
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# exiting until any background operations are completed
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@launcher.config.run_hooks :before_worker_shutdown, index, @launcher.events
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ensure
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@worker_write << "t#{Process.pid}\n" rescue nil
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@worker_write.close
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end
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def restart
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@restart = true
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stop
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end
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def phased_restart
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return false if @options[:preload_app]
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@phased_restart = true
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wakeup!
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true
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end
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def stop
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@status = :stop
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wakeup!
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end
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def stop_blocked
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@status = :stop if @status == :run
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wakeup!
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@control.stop(true) if @control
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Process.waitall
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end
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def halt
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@status = :halt
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wakeup!
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end
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def reload_worker_directory
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dir = @launcher.restart_dir
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log "+ Changing to #{dir}"
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Dir.chdir dir
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end
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# Inside of a child process, this will return all zeroes, as @workers is only populated in
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# the master process.
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def stats
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old_worker_count = @workers.count { |w| w.phase != @phase }
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worker_status = @workers.map do |w|
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{
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started_at: w.started_at.utc.iso8601,
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pid: w.pid,
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index: w.index,
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phase: w.phase,
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booted: w.booted?,
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last_checkin: w.last_checkin.utc.iso8601,
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last_status: w.last_status,
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}
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end
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{
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started_at: @started_at.utc.iso8601,
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workers: @workers.size,
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phase: @phase,
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booted_workers: worker_status.count { |w| w[:booted] },
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old_workers: old_worker_count,
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worker_status: worker_status,
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}
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end
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def preload?
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@options[:preload_app]
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end
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def fork_worker!
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if (worker = @workers.find { |w| w.index == 0 })
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worker.phase += 1
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end
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phased_restart
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end
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# We do this in a separate method to keep the lambda scope
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# of the signals handlers as small as possible.
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def setup_signals
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if @options[:fork_worker]
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Signal.trap "SIGURG" do
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fork_worker!
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end
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# Auto-fork after the specified number of requests.
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if (fork_requests = @options[:fork_worker].to_i) > 0
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@launcher.events.register(:ping!) do |w|
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fork_worker! if w.index == 0 &&
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w.phase == 0 &&
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w.last_status[:requests_count] >= fork_requests
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end
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end
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end
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Signal.trap "SIGCHLD" do
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wakeup!
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end
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Signal.trap "TTIN" do
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@options[:workers] += 1
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wakeup!
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end
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Signal.trap "TTOU" do
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@options[:workers] -= 1 if @options[:workers] >= 2
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wakeup!
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end
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master_pid = Process.pid
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Signal.trap "SIGTERM" do
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# The worker installs their own SIGTERM when booted.
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# Until then, this is run by the worker and the worker
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# should just exit if they get it.
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if Process.pid != master_pid
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log "Early termination of worker"
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exit! 0
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else
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@launcher.close_binder_listeners
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stop_workers
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stop
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raise(SignalException, "SIGTERM") if @options[:raise_exception_on_sigterm]
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exit 0 # Clean exit, workers were stopped
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end
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end
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end
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def run
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@status = :run
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output_header "cluster"
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log "* Process workers: #{@options[:workers]}"
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before = Thread.list
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if preload?
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log "* Preloading application"
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load_and_bind
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after = Thread.list
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if after.size > before.size
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threads = (after - before)
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if threads.first.respond_to? :backtrace
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log "! WARNING: Detected #{after.size-before.size} Thread(s) started in app boot:"
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threads.each do |t|
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log "! #{t.inspect} - #{t.backtrace ? t.backtrace.first : ''}"
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end
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else
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log "! WARNING: Detected #{after.size-before.size} Thread(s) started in app boot"
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end
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end
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else
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log "* Phased restart available"
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unless @launcher.config.app_configured?
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error "No application configured, nothing to run"
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exit 1
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end
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@launcher.binder.parse @options[:binds], self
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end
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read, @wakeup = Puma::Util.pipe
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setup_signals
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# Used by the workers to detect if the master process dies.
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# If select says that @check_pipe is ready, it's because the
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# master has exited and @suicide_pipe has been automatically
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# closed.
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#
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@check_pipe, @suicide_pipe = Puma::Util.pipe
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# Separate pipe used by worker 0 to receive commands to
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# fork new worker processes.
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@fork_pipe, @fork_writer = Puma::Util.pipe
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log "Use Ctrl-C to stop"
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redirect_io
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Plugins.fire_background
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@launcher.write_state
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start_control
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@master_read, @worker_write = read, @wakeup
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@launcher.config.run_hooks :before_fork, nil, @launcher.events
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GC.compact if GC.respond_to?(:compact)
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spawn_workers
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Signal.trap "SIGINT" do
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stop
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end
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@launcher.events.fire_on_booted!
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begin
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while @status == :run
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begin
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if @phased_restart
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start_phased_restart
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@phased_restart = false
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end
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check_workers
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res = IO.select([read], nil, nil, [0, @next_check - Time.now].max)
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if res
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req = read.read_nonblock(1)
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@next_check = Time.now if req == "!"
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next if !req || req == "!"
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result = read.gets
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pid = result.to_i
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if req == "b" || req == "f"
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pid, idx = result.split(':').map(&:to_i)
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w = @workers.find {|x| x.index == idx}
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w.pid = pid if w.pid.nil?
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end
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if w = @workers.find { |x| x.pid == pid }
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case req
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when "b"
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w.boot!
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log "- Worker #{w.index} (pid: #{pid}) booted, phase: #{w.phase}"
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@next_check = Time.now
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when "e"
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# external term, see worker method, Signal.trap "SIGTERM"
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w.instance_variable_set :@term, true
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when "t"
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w.term unless w.term?
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when "p"
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|
w.ping!(result.sub(/^\d+/,'').chomp)
|
|
@launcher.events.fire(:ping!, w)
|
|
end
|
|
else
|
|
log "! Out-of-sync worker list, no #{pid} worker"
|
|
end
|
|
end
|
|
|
|
rescue Interrupt
|
|
@status = :stop
|
|
end
|
|
end
|
|
|
|
stop_workers unless @status == :halt
|
|
ensure
|
|
@check_pipe.close
|
|
@suicide_pipe.close
|
|
read.close
|
|
@wakeup.close
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
# loops thru @workers, removing workers that exited, and calling
|
|
# `#term` if needed
|
|
def wait_workers
|
|
@workers.reject! do |w|
|
|
next false if w.pid.nil?
|
|
begin
|
|
if Process.wait(w.pid, Process::WNOHANG)
|
|
true
|
|
else
|
|
w.term if w.term?
|
|
nil
|
|
end
|
|
rescue Errno::ECHILD
|
|
begin
|
|
Process.kill(0, w.pid)
|
|
false # child still alive, but has another parent
|
|
rescue Errno::ESRCH, Errno::EPERM
|
|
true # child is already terminated
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
def timeout_workers
|
|
@workers.each do |w|
|
|
if !w.term? && w.ping_timeout <= Time.now
|
|
log "! Terminating timed out worker: #{w.pid}"
|
|
w.kill
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end
|