Class: Async::Container::Notify::Pipe

Inherits:
Client
  • Object
show all
Defined in:
lib/async/container/notify/pipe.rb

Overview

Implements a process readiness protocol using an inherited pipe file descriptor.

Constant Summary collapse

NOTIFY_PIPE =

The environment variable key which contains the pipe file descriptor.

"NOTIFY_PIPE"

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Client

#error!, #ready!, #reloading!, #restarting!, #status!, #stopping!

Constructor Details

#initialize(io) ⇒ Pipe

Initialize the notification client.



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# File 'lib/async/container/notify/pipe.rb', line 32

def initialize(io)
	@io = io
end

Class Method Details

.open!(environment = ENV) ⇒ Object

Open a notification client attached to the current NOTIFY_PIPE if possible.



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# File 'lib/async/container/notify/pipe.rb', line 20

def self.open!(environment = ENV)
	if descriptor = environment.delete(NOTIFY_PIPE)
		self.new(::IO.for_fd(descriptor.to_i))
	end
rescue Errno::EBADF => error
	Console.error(self) {error}
	
	return nil
end

Instance Method Details

#before_spawn(arguments, options) ⇒ Object

Inserts or duplicates the environment given an argument array. Sets or clears it in a way that is suitable for Process.spawn.



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# File 'lib/async/container/notify/pipe.rb', line 38

def before_spawn(arguments, options)
	environment = environment_for(arguments)
	
	# Use `notify_pipe` option if specified:
	if notify_pipe = options.delete(:notify_pipe)
		options[notify_pipe] = @io
		environment[NOTIFY_PIPE] = notify_pipe.to_s
		
	# Use stdout if it's not redirected:
	# This can cause issues if the user expects stdout to be connected to a terminal.
	# elsif !options.key?(:out)
	# 	options[:out] = @io
	# 	environment[NOTIFY_PIPE] = "1"
		
	# Use fileno 3 if it's available:
	elsif !options.key?(3)
		options[3] = @io
		environment[NOTIFY_PIPE] = "3"
		
	# Otherwise, give up!
	else
		raise ArgumentError, "Please specify valid file descriptor for notify_pipe!"
	end
end

#send(**message) ⇒ Object

Formats the message using JSON and sends it to the parent controller. This is suitable for use with Channel.



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# File 'lib/async/container/notify/pipe.rb', line 65

def send(**message)
	data = ::JSON.dump(message)
	
	@io.puts(data)
	@io.flush
end