Asynchronous function calls using lovely.remotetask
Project description
gocept.async provides asynchronous function calls using a decorator. It facilitates lovely.remotetask to actually do things asynchronously.
Details
It is often desirable to process computations asynchronously. Until there was lovely.remotetask this was not so easy to achieve in a Zope 3 application due to transaction integration issues.
gocept.async makes the task even easier:
>>> import gocept.async >>> @gocept.async.function(service='events') ... def heavy_computing(a, b): ... print "Computing", a, "+", b, "=", a + b
The decorator gocept.async.function takes exactly one argument, the name of a lovely.remotetask.interfaces.ITaskService utility. Note that gocept.async does not define any task service by itself.
Test Setup
Note that the decorated function must have an importable module to be usable:
>>> import gocept.async.tests >>> heavy_computing.undecorated.__module__ = 'gocept.async.tests' >>> gocept.async.tests.heavy_computing = heavy_computing
We defined task-service called events in this test:
>>> import zope.component >>> import lovely.remotetask >>> import lovely.remotetask.interfaces >>> import lovely.remotetask.processor >>> sm = zope.component.getSiteManager() >>> getRootFolder()['tasks'] = tasks = lovely.remotetask.TaskService() >>> tasks.processorFactory = lovely.remotetask.processor.MultiProcessor >>> tasks.processorArguments = {'maxThreads': 1} >>> sm.registerUtility( ... tasks, lovely.remotetask.interfaces.ITaskService, name='events')
Basics
When the decorated function is called it returns nothing:
>>> heavy_computing(2, 7)
When we start the processing of the task service, the function is called:
>>> gocept.async.tests.process() Computing 2 + 7 = 9
When the function is called while a user is logged in, the function will be called as that user (Note that it might be necessary to manually create security proxies to enable security in the async function.):
>>> @gocept.async.function('events') ... def who_am_i(): ... print gocept.async.task.TaskDescription.get_principal() ... >>> who_am_i.undecorated.__module__ = 'gocept.async.tests' >>> gocept.async.tests.who_am_i = who_am_i >>> who_am_i() >>> gocept.async.tests.process()
Now login:
>>> gocept.async.tests.login('zope.user') >>> who_am_i() >>> gocept.async.tests.process() zope.user >>> gocept.async.tests.logout()
If an async function is called while the process is already async’ed the function is called immediately:
>>> @gocept.async.function(service='events') ... def call_another(): ... print "Before" ... heavy_computing(1, 2) ... print "After" >>> call_another.undecorated.__module__ = 'gocept.async.tests' >>> gocept.async.tests.call_another = call_another >>> call_another() >>> gocept.async.tests.process() Before Computing 1 + 2 = 3 After
There is a helper to test if currenlty async is in progress:
>>> gocept.async.is_async() False >>> @gocept.async.function(service='events') ... def is_async_test(): ... print gocept.async.is_async() >>> is_async_test.undecorated.__module__ = 'gocept.async.tests' >>> gocept.async.tests.is_async_test = is_async_test >>> is_async_test() >>> gocept.async.tests.process() True
Teardown
>>> sm.registerUtility( ... tasks, lovely.remotetask.interfaces.ITaskService, name='events') >>> del gocept.async.tests.heavy_computing >>> del gocept.async.tests.who_am_i >>> del gocept.async.tests.call_another >>> del gocept.async.tests.is_async_test
Changes
0.3.3 (2011-04-05)
Replace deprecated zope.testing.doctest with stdlib’s doctest.
0.3.2 (2010-04-14)
Fix conflict error logging.
0.3.1 (2009-09-02)
Extracted a function to determine wether a function is run asynchronously or not.
0.3 (2009-07-31)
Remember the site that was active when the async function was defined and restore it when it is run.
0.2 (2009-04-16)
Made it even less likely that tests will raise ConflictErrors.
Fixed tests in README.
0.1.1 (2009-02-11)
Made it less likely that tests will raise ConflictErrors.
0.1 (2009-02-11)
first internal release.
Project details
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