Run your task asynchronously, communicate and control them with ease
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README.md

task.py

Run your task asynchronously in the background and control/communicate with them.

Build Status

Install

pip install task.py

Usage

Basic use case of task.py is to run some unit of work asynchronously (in a separate thread or process) while being able to control and communicate with that unit of work. Example:

Lets define a simple_task that:

  • Expects some arguments
  • Does some work (sleep) until signaled to stop
  • return "done." as final result
>>> def simple_task(t): # will receive a Task instance as first argument
...     assert t.args[0] == 'hello'
...     assert t.kwargs['world'] == 'world'
...     while not t.stopped():
...         time.sleep(0.1)
...     return 'done.'

Next, create a Task instance with simple_task as unit to work. Additionally specify arguments expected by our sleep_task:

>>> t1 = Task(simple_task, 'hello', world='world')
>>>
>>> # start our task asynchronously
>>> t1.start()
>>>
>>> # after 1 second signal our task to stop
>>> time.sleep(1)
>>> t1.stop()
>>>
>>> t1.done
True
>>>
>>> t1.result
'done.'
>>>
>>> t1.exception == None
True

Lets create a new Task instance, this time skipping the expected arguments:

>>> t2 = Task(simple_task)
>>>
>>> # start our task asynchronously
>>> t2.start()
>>>
>>> t2.done
True
>>>
>>> # No result found
>>> t2.result == None
True
>>>
>>> # our task raised an exception
>>> t2.exception
IndexError('tuple index out of range',)

Communicating with Task

Task provide a communication queue over which external threads can send data to the executing unit of work. Example:

Lets define a sleep_task which will receive amount of time to sleep over the communication queue:

>>> def sleep_task(t):
...     secs = t.recv() # recv API, default blocks until we have some data
...     time.sleep(int(secs))
...
>>> t3 = Task(sleep_task)
>>> t3.start()
>>>
>>> # our task is waiting
>>> t3.done
False
>>>
>>> # send 1 sec sleep time
>>> t3.send(1)
>>>
>>> # alright, done
>>> t3.done
True

Controllers

Task and Celery