thimble 0.2.0

Quick start

The main object you’re interested in is thimble.Thimble. It takes a thread pool, a blocking object, and a list of method names that you would like to defer to the thread pool.

Here’s our example blocking object:

>>> class Car(object):
...     wheels = 4
...     def drive_to(self, location):
...          # Assume the real implementation blocks.
...          return "driven to {0}".format(location)
>>> car = Car()

For demonstration purposes, we’ll use a test doubles for the thread pool and reactor; in real code, you’ll want to use the real thing.

>>> from thimble.test.util import FakeThreadPool, FakeReactor
>>> pool = FakeThreadPool()
>>> reactor = FakeReactor()

The pool hasn’t been started yet. (We’ll see why that matters in a minute.)

>>> pool.started
False

Create a Thimble:

>>> from thimble import Thimble
>>> car_thimble = Thimble(reactor, pool, car, ["drive_to"])

When accessing a method named in the list, you get an object wrapping it instead. Calling it returns a Deferred. Any arguments passed are passed verbatim to the wrapped method.

>>> def print_(s):
...     # can't use from __future__ import print_function because of a
...     # doctest limitation :-(
...     print s

>>> d = car_thimble.drive_to("work").addCallback(print_)
driven to work

This Deferred has already fired synchronously, because we’re using a fake thread pool and reactor.

You can access other attributes of the wrapped object directly on the Thimble:

>>> car.wheels
4

If the thread pool that you pass to a Thimble hasn’t been started yet when it first tries to use it, the Thimble will start it and schedule its shutdown. If you pass a thread pool that was already started, you are responsible for its shutdown. In this case, the thread pool was not started yet, so Thimble started it for you:

>>> pool.started
True

Shut down the reactor, and the reactor will ask the thread pool to stop right before shutting down itself.

>>> reactor.stop()
>>> pool.started
False

from twisted.python.threadpool import ThreadPool
_the_thread_pool = _ThreadPool()

Changelog

Thimble uses SemVer.