Class: By::Worker

Inherits:
Object
  • Object
show all
Defined in:
lib/by/worker.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(socket) ⇒ Worker

Create the worker. Arguments

socket

The Unix socket to use to communicate with the client.

sigterm_handler



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# File 'lib/by/worker.rb', line 14

def initialize(socket)
  @socket = socket
  @normal_exit = nil
end

Instance Attribute Details

#normal_exit=(value) ⇒ Object (writeonly)

Whether the worker process should signal a normal exit to the client. The default is nil, which signals a normal exit when the worker process exits normally. This can be set to false to signal an abnormal exit, such as to indicate test failures.



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# File 'lib/by/worker.rb', line 9

def normal_exit=(value)
  @normal_exit = value
end

Instance Method Details

#chdir(dir) ⇒ Object

Change to the given directory.



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# File 'lib/by/worker.rb', line 78

def chdir(dir)
  Dir.chdir(dir)
end

#chdir_or_stop ⇒ Object

Change to the given directory, unless the client is telling the worker to stop the server.



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# File 'lib/by/worker.rb', line 44

def chdir_or_stop
  arg = @socket.readline("\0", chomp: true)
  arg == 'stop' ? stop_server : chdir(arg)
end

#cleanup_proc ⇒ Object

A proc for communicating exit status to the client, and printing the loaded features if configured. Used during process shutdown.



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# File 'lib/by/worker.rb', line 90

def cleanup_proc
  proc do
    if @normal_exit.nil?
      @normal_exit = $!.nil? || ($!.is_a?(SystemExit) && $!.success?)
    end
    @socket.write(@normal_exit ? '0' : '1')
    @socket.shutdown(Socket::SHUT_WR)
    @socket.close
    print_loaded_features if ENV['DEBUG'] == 'log'
  end
end

#get_args ⇒ Object

An array of arguments provided by the client.



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# File 'lib/by/worker.rb', line 114

def get_args
  args = []
  while !@socket.eof?
    args << @socket.readline("\0", chomp: true)
  end
  args
end

#handle_args(args) ⇒ Object

Handle arguments provided by the client. Ensure correct client after handling the arguments.



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# File 'lib/by/worker.rb', line 124

def handle_args(args)
  worker = self
  cleanup = cleanup_proc

  case arg = args.first
  when 'm', /\.rb:\d+\z/
    args.shift if arg == 'm'
    ARGV.replace(args)
    require 'm'
    M.define_singleton_method(:exit!) do |exit_code|
      worker.normal_exit = exit_code == true
      cleanup.call
      super(exit_code)
    end
    M.run(args)
  when 'irb'
    at_exit(&cleanup)
    args.shift
    ARGV.replace(args)
    require 'irb'
    IRB.start(__FILE__)
  when '-e'
    at_exit(&cleanup)
    unless args.length >= 2
      $stderr.puts 'no code specified for -e (RuntimeError)'
      exit(1)
    end
    args.shift
    code = args.shift
    ARGV.replace(args)
    ::TOPLEVEL_BINDING.eval(code)
  when String
    args.shift
    ARGV.replace(args)

    begin
      require File.expand_path(arg)
    rescue
      @normal_exit = false
      at_exit(&cleanup)
      raise
    end

    if defined?(Minitest) && Minitest.class_variable_get(:@@installed_at_exit)
      Minitest.singleton_class.prepend(Module.new do
        define_method(:run) do |argv|
          super(argv).tap{|exit_code| worker.normal_exit = exit_code == true}
        end
      end)
      Minitest.after_run(&cleanup)
    else
      at_exit(&cleanup)
    end
  else
    # no arguments
    at_exit(&cleanup)
    ::TOPLEVEL_BINDING.eval($stdin.read)
  end
end

#print_loaded_features ⇒ Object

Print $LOADED_FEATURES to stdout.



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# File 'lib/by/worker.rb', line 83

def print_loaded_features
  puts $LOADED_FEATURES
end

#reopen_stdio ⇒ Object

Replace stdin, stdout, stderr with the IO values provided by the client.



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# File 'lib/by/worker.rb', line 36

def reopen_stdio
  $stdin.reopen(@socket.recv_io(IO))
  $stdout.reopen(@socket.recv_io(IO))
  $stderr.reopen(@socket.recv_io(IO))
end

#replace_env ⇒ Object

Replace ENV with the environment provided by the client.



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# File 'lib/by/worker.rb', line 103

def replace_env
  env = {}
  while line = @socket.readline("\0", chomp: true)
    break if line.empty?
    k, v = line.split("=")
    env[k] = v
  end
  ENV.replace(env)
end

#run ⇒ Object

Run the worker process.



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# File 'lib/by/worker.rb', line 20

def run
  write_pid
  reopen_stdio
  chdir_or_stop
  replace_env
  handle_args(get_args)
end

#stop_server ⇒ Object

Stop the server process by sending it the SIGQUIT signal, then exit.



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# File 'lib/by/worker.rb', line 50

def stop_server
  i = 0
  while Process.ppid != 1 && Process.kill(0, Process.ppid)
    if i < 4
      Process.kill(:QUIT, Process.ppid)
    end
    sleep 0.1

    if i == 5
      # This is only reached if the QUIT signal does not
      # cause the process to exit.
      Process.kill(:KILL, Process.ppid)
    end
    if i > 8
      # This is only reached if the process has still not
      # stopped even after the KILL signal was sent.
      $stderr.puts "ERROR: cannot stop by-server"
      @normal_exit = false
      break
    end

    i += 1
  end
  cleanup_proc.call
  exit
end

#write_pid ⇒ Object

Write the current process pid to the client, to signal that the worker process is ready.



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# File 'lib/by/worker.rb', line 30

def write_pid
  @socket.write($$.to_s)
  @socket.write("\0")
end