Class: Puma::Cluster::Worker

Inherits:
Runner
  • Object
show all
Defined in:
lib/puma/cluster/worker.rb

Overview

This class is instantiated by the ‘Puma::Cluster` and represents a single worker process.

At the core of this class is running an instance of ‘Puma::Server` which gets created via the `start_server` method from the `Puma::Runner` class that this inherits from.

Instance Attribute Summary collapse

Attributes inherited from Runner

#app, #options, #ruby_engine

Instance Method Summary collapse

Methods inherited from Runner

#close_control_listeners, #debug, #development?, #error, #load_and_bind, #log, #output_header, #redirect_io, #redirected_io?, #start_control, #start_server, #stop_control, #test?, #wakeup!

Constructor Details

#initialize(index:, master:, launcher:, pipes:, server: nil) ⇒ Worker

Returns a new instance of Worker.



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# File 'lib/puma/cluster/worker.rb', line 17

def initialize(index:, master:, launcher:, pipes:, server: nil)
  super(launcher)

  @index = index
  @master = master
  @check_pipe = pipes[:check_pipe]
  @worker_write = pipes[:worker_write]
  @fork_pipe = pipes[:fork_pipe]
  @wakeup = pipes[:wakeup]
  @server = server
  @hook_data = {}
end

Instance Attribute Details

#index ⇒ Object (readonly)

:nodoc:



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# File 'lib/puma/cluster/worker.rb', line 15

def index
  @index
end

#master ⇒ Object (readonly)

:nodoc:



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# File 'lib/puma/cluster/worker.rb', line 15

def master
  @master
end

Instance Method Details

#run ⇒ Object 



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# File 'lib/puma/cluster/worker.rb', line 30

def run
  title  = "puma: cluster worker #{index}: #{master}"
  title += " [#{@options[:tag]}]" if @options[:tag] && !@options[:tag].empty?
  $0 = title

  Signal.trap "SIGINT", "IGNORE"
  Signal.trap "SIGCHLD", "DEFAULT"

  Thread.new do
    Puma.set_thread_name "wrkr check"
    @check_pipe.wait_readable
    log "! Detected parent died, dying"
    exit! 1
  end

  # If we're not running under a Bundler context, then
  # report the info about the context we will be using
  if !ENV['BUNDLE_GEMFILE']
    if File.exist?("Gemfile")
      log "+ Gemfile in context: #{File.expand_path("Gemfile")}"
    elsif File.exist?("gems.rb")
      log "+ Gemfile in context: #{File.expand_path("gems.rb")}"
    end
  end

  # Invoke any worker boot hooks so they can get
  # things in shape before booting the app.
  @config.run_hooks(:before_worker_boot, index, @log_writer, @hook_data)

  begin
  server = @server ||= start_server
  rescue Exception => e
    log "! Unable to start worker"
    log e
    log e.backtrace.join("\n    ")
    exit 1
  end

  restart_server = Queue.new << true << false

  fork_worker = @options[:fork_worker] && index == 0

  if fork_worker
    restart_server.clear
    worker_pids = []
    Signal.trap "SIGCHLD" do
      wakeup! if worker_pids.reject! do |p|
        Process.wait(p, Process::WNOHANG) rescue true
      end
    end

    Thread.new do
      Puma.set_thread_name "wrkr fork"
      while (idx = @fork_pipe.gets)
        idx = idx.to_i
        if idx == -1 # stop server
          if restart_server.length > 0
            restart_server.clear
            server.begin_restart(true)
            @config.run_hooks(:before_refork, nil, @log_writer, @hook_data)
          end
        elsif idx == 0 # restart server
          restart_server << true << false
        else # fork worker
          worker_pids << pid = spawn_worker(idx)
          @worker_write << "f#{pid}:#{idx}\n" rescue nil
        end
      end
    end
  end

  Signal.trap "SIGTERM" do
    @worker_write << "e#{Process.pid}\n" rescue nil
    restart_server.clear
    server.stop
    restart_server << false
  end

  begin
    @worker_write << "b#{Process.pid}:#{index}\n"
  rescue SystemCallError, IOError
    Puma::Util.purge_interrupt_queue
    STDERR.puts "Master seems to have exited, exiting."
    return
  end

  while restart_server.pop
    server_thread = server.run

    if @log_writer.debug? && index == 0
      debug_loaded_extensions "Loaded Extensions - worker 0:"
    end

    stat_thread ||= Thread.new(@worker_write) do |io|
      Puma.set_thread_name "stat pld"
      base_payload = "p#{Process.pid}"

      while true
        begin
          b = server.backlog || 0
          r = server.running || 0
          t = server.pool_capacity || 0
          m = server.max_threads || 0
          rc = server.requests_count || 0
          payload = %Q!#{base_payload}{ "backlog":#{b}, "running":#{r}, "pool_capacity":#{t}, "max_threads": #{m}, "requests_count": #{rc} }\n!
          io << payload
        rescue IOError
          Puma::Util.purge_interrupt_queue
          break
        end
        sleep @options[:worker_check_interval]
      end
    end
    server_thread.join
  end

  # Invoke any worker shutdown hooks so they can prevent the worker
  # exiting until any background operations are completed
  @config.run_hooks(:before_worker_shutdown, index, @log_writer, @hook_data)
ensure
  @worker_write << "t#{Process.pid}\n" rescue nil
  @worker_write.close
end