Installation

pip install tornado-slacker

Slackers and workers

In order to execute some code in non-blocking manner:

1. Create a Slacker (configured with the desired worker) for some python object:

   from slacker import Slacker
   from slacker.workers import ThreadWorker
   
   class Foo(object):
       # ...
   
   worker = ThreadWorker()
   AsyncFoo = Slacker(Foo, worker)

2. build a query (you can access attributes, do calls and slicing):

   query = AsyncFoo('foo').do_blocking_operation(param1, param2)[0]

3. execute the query:

   def callback(result):
       # ...
   
   query.proceed(callback)

   or, using pep-342 style:

   from slacker import adisp
   
   @adisp.process
   def handler():
       result = yield query
       # ...

Slackers

Slackers are special objects that are collecting operations (attribute access, calls, slicing) without actually executing them:

>>> from slacker import Slacker
>>> class Foo():
...     pass
...
>>> FooSlacker = Slacker(Foo)
>>> FooSlacker.hello.world()
__main__.Foo: [('hello',), ('world', (), {})]

>>> FooSlacker(name='me').hello.world(1, y=3)[:3]
__main__.Foo: [(None, (), {'name': 'me'}),
 ('hello',),
 ('world', (1,), {'y': 3}),
 (slice(None, 3, None), None)]

Callables arguments must be picklable. Slackers also provide a method to apply the collected operations to a base object.

Any picklable object (including top-level functions and classes) can be wrapped into Slacker, e.g.:

from slacker import adisp
from slacker import Slacker
from slacker.workers import ThreadWorker

def task(param1, param2):
    # do something blocking and io-bound
    return results

async_task = Slacker(task, ThreadWorker())

# pep-342-style
@adisp.process
def process_data():
    results = yield async_task('foo', 'bar')
    print results

# callback style
def process_data2():
    async_task('foo', 'bar').proceed(on_result)

def on_result(results):
    print results

Python modules also can be Slackers:

import shutil
from slacker import Slacker
from slacker.workers import ThreadWorker

shutil_async = Slacker(shutil, ThreadWorker())
op = shutil_async.copy('file1.txt', 'file2.txt')
op.proceed()

Workers

Workers are classes that decides how and where the work should be done:

• slacker.workers.DummyWorker executes code in-place (this is blocking);

• slacker.workers.ThreadWorker executes code in a thread from a thread pool;

• slacker.workers.HttpWorker pickles the slacker, makes an async http request with this data to a given server hook and expects it to execute the code and return pickled results;

• slacker.workers.DjangoWorker is just a HttpWorker with default values for use with bundled django remote server hook implementation (slacker.django_backend).

  In order to enable django hook, include ‘slacker.django_backend.urls’ into urls.py and add SLACKER_SERVER option with server address to settings.py.

  SLACKER_SERVER is ‘127.0.0.1:8000’ by default so this should work for development server out of box.

Parallel execution

Parallel task execution is supported by adisp library:

def _task1(param1, param2):
    # do something blocking
    return results

def _task2():
    # do something blocking
    return results

# worker can be reused
worker = ThreadWorker()
task1 = Slacker(_task1, worker)
task2 = Slacker(_task2, worker)

@adisp.process
def process_data():
    # this will execute task1 and task2 in parallel
    # and return the result after all data is ready
    res1, res2 = yield task1('foo', 'bar'), task2()
    print res1, res2

Contributing

If you have any suggestions, bug reports or annoyances please report them to the issue tracker:

• https://github.com/kmike/tornado-slacker/issues

Source code:

• https://bitbucket.org/kmike/tornado-slacker/

• https://github.com/kmike/tornado-slacker/

Both hg and git pull requests are welcome!

Credits

Inspiration:

• https://github.com/satels/django-async-dbslayer/

• https://bitbucket.org/david/django-roa/

• http://tornadogists.org/654157/

Third-party software:

• adisp (tornado adisp implementation is taken from brukva);

• exception serialization utils are from billiard by Ask Solem.

License

The license is MIT.

Bundled adisp library uses Simplified BSD License.

slacker.serialization is under BSD License.