Module: Zeus

Defined in:
lib/zeus.rb,
lib/zeus/m.rb,
lib/zeus/plan.rb,
lib/zeus/rails.rb,
lib/zeus/version.rb,
lib/zeus/load_tracking.rb,
lib/zeus/m/test_method.rb,
lib/zeus/m/test_collection.rb

Defined Under Namespace

Modules: M Classes: LoadTracking, Plan, Rails

Constant Summary collapse

VERSION = 
"0.16.0"

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.dummy_tty ⇒ Object

Returns the value of attribute dummy_tty.



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# File 'lib/zeus.rb', line 19

def dummy_tty
  @dummy_tty
end

.master_socket ⇒ Object

Returns the value of attribute master_socket.



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# File 'lib/zeus.rb', line 19

def master_socket
  @master_socket
end

.plan ⇒ Object

Returns the value of attribute plan.



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# File 'lib/zeus.rb', line 19

def plan
  @plan
end

Class Method Details

.boot_steps(identifier) ⇒ Object 



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# File 'lib/zeus.rb', line 54

def boot_steps(identifier)
  while true
    boot_step = catch(:boot_step) do
      $0 = "zeus slave: #{identifier}"

      setup_dummy_tty!
      master = setup_master_socket!
      feature_pipe_r, feature_pipe_w = IO.pipe

      # I need to give the master a way to talk to me exclusively
      local, remote = UNIXSocket.pair(Socket::SOCK_STREAM)
      master.send_io(remote)

      # Now I need to tell the master about my PID and ID
      local.write "P:#{Process.pid}:#{@parent_pid || 0}:#{identifier}\0"
      local.send_io(feature_pipe_r)
      feature_pipe_r.close

      Zeus::LoadTracking.set_feature_pipe(feature_pipe_w)

      run_action(local, identifier)

      # We are now 'connected'. From this point, we may receive requests to fork.
      children = Set.new
      while true
        messages = local.recv(2**16)

        # Reap any child runners or slaves that might have exited in
        # the meantime. Note that reaping them like this can leave <=1
        # zombie process per slave around while the slave waits for a
        # new command.
        children.each do |pid|
          children.delete(pid) if Process.waitpid(pid, Process::WNOHANG)
        end

        messages.split("\0").each do |new_identifier|
          new_identifier =~ /^(.):(.*)/
          code, ident = $1, $2

          forked_from = Process.pid

          pid = fork
          if pid
            # We're in the parent. Record the child:
            children << pid
          elsif code == "S"
            # Child, supposed to start another step:
            @parent_pid = forked_from

            Zeus::LoadTracking.clear_feature_pipe

            throw(:boot_step, ident.to_sym)
          else
            # Child, supposed to run a command:
            @parent_pid = forked_from

            Zeus::LoadTracking.clear_feature_pipe

            return [ident.to_sym, local]
          end
        end
      end
    end
    identifier = boot_step
  end
end

.go(identifier = :boot) ⇒ Object 



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# File 'lib/zeus.rb', line 44

def go(identifier=:boot)
  # Thanks to the magic of fork, this following line will return
  # many times: Every time the parent step receives a request to
  # run a command.
  if run_command = boot_steps(identifier)
    ident, local = run_command
    return command(ident, local)
  end
end

.setup_dummy_tty! ⇒ Object

this is totally asinine, but readline gets super confused when it’s required at a time when stdin or stdout is not connected to a TTY, no matter what we do to tell it otherwise later. So we create a dummy TTY in case readline is required.

Yup.



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# File 'lib/zeus.rb', line 27

def setup_dummy_tty!
  return if self.dummy_tty
  master, self.dummy_tty = PTY.send(:open)
  Thread.new {
    loop { master.read(1024) }
  }
  STDIN.reopen(dummy_tty)
  STDOUT.reopen(dummy_tty)
end

.setup_master_socket! ⇒ Object 



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# File 'lib/zeus.rb', line 37

def setup_master_socket!
  return master_socket if master_socket

  fd = ENV['ZEUS_MASTER_FD'].to_i
  self.master_socket = UNIXSocket.for_fd(fd)
end