Implement special channels (NIL, VOID)

[mschatten]

Most TODO's are already implemented (channel subscription). What needs to be done is to implement NIL channel (needs to be connected to agent's stopping behaviour) and void channel (sending output to /dev/null)

APi/agent.py

Lines 242 to 288 in e1208c0

	def subscribe_to_channel( self, channel, channel_type ):
	# TODO: Implement channel subscription (sender, receiver)
	# Channel types:
	# NIL -> sends stop to agent (0 process)
	# VOID -> sends output to /dev/null
	# STDIN -> reads input from stdin
	# STDOUT/STDERR -> writes output to STDIN/STDERR
	# <name> -> gets instructions from channel on how
	# to connect (via Netcat)
	if channel_type == 'input':
	if channel == 'NIL':
	err = 'Input cannot be 0 (NIL)'
	raise APiChannelDefinitionError( err )
	elif channel == 'VOID':
	err = 'Input cannot be VOID'
	raise APiChannelDefinitionError( err )
	elif channel == 'STDOUT':
	err = 'Input cannot be STDOUT'
	raise APiChannelDefinitionError( err )
	elif channel == 'STDERR':
	err = 'Input cannot be STDERR'
	raise APiChannelDefinitionError( err )
	elif channel == 'STDIN':
	self.start_shell_client( prompt=True, await_stdin=True )
	else:
	self.say( 'Adding input channel', channel )
	self.input_channel_query_buffer.append( channel )
	elif channel_type == 'output':
	if channel == 'NIL':
	# TODO: stop agent
	raise NotImplementedError( NIE )
	elif channel == 'VOID':
	# TODO: send to /dev/null (i.e. do nothing )
	raise NotImplementedError( NIE )
	elif channel == 'STDOUT':
	self.start_shell_client( print_stdout=True )
	elif channel == 'STDERR':
	self.start_shell_client( print_stderr=False )
	elif channel == 'STDIN':
	err = 'Output cannot be STDIN'
	raise APiChannelDefinitionError( err )
	else:
	# TODO: send message to channel agent
	# and get instructions on how to
	# connect
	self.say( 'Adding output channel', channel )
	self.output_channel_query_buffer.append( channel )