Messages#

A message is a data container used to exchange data across nodes.

property	type	description
`self.creator`	`str`	name or id of the creating node
`self.version`	`int`	message data version
`self.payload`	`Any`	data to be transferred upstream in the pipeline
`self.meta`	`dict`	message metadata
`self.timers`	`dict`	collection of timers to evaluate performed data operations

An empty message is created with:

creator set to None
version set to -1
payload set to None

method	arguments	description
`Message.from_message()`	`(Message, bool)`	create a message by copying another message
`self.to_dict()`	`()`	convert the message to dict
`self.to_json()`	`(callable)`	convert the message to json string, with a provided encoder
`self.timer()`	`(str, float)`	add timer to message

Notes:

currently, to_json() simply returns the json.dumps() on the dictionary version of a message; this means that generating a json string for the message will fail if the message payload is not serialisable using the encoder function provided as argument

Timers#

In order to keep track of any operations performed to generate the data contained in a message, a context manager, timeit, is offered to automatically create within the message timers dictionary a relevant entry.

>>> m = Message()
>>> with m.timeit('timer_name'):
>>>     time.sleep(1)
>>> m.timers
{'timer_name': 1.001392364501953}

Alternatively, set a timer using the timer() method:

>>> m = Message()
>>> m.timer('timer_name', 1.1)
>>> m.timers
{'timer_name': 1.1}