Context loop (cl)¶

Simple context manager utility for asyncio event loop. Context loop helps with async pieces of code to be scheduled and run within synchronous code.

Can be used with synchronous and asynchronous frameworks like Django, Flask or Tornado and Twisted.

Context loop¶

Info:	Context loop.
Author:	Paweł Zadrożny @pawelzny <pawel.zny@gmail.com>

Features¶

Work with sync and async frameworks
Schedule tasks to existing loop or create new one
No need to understand how async works
No callbacks required
Run async tasks whenever and wherever you want

Installation¶

pip install context-loop

Package: https://pypi.org/project/context-loop/

Documentation¶

Read full documentation at http://context-loop.readthedocs.io/en/stable/

Quick Example¶

>>> async def coro():
...     return await something_from_future()
...
>>> import cl.Loop
>>> with cl.Loop(coro(), coro(), coro()) as loop:
...    result = loop.run_until_complete()
...
>>> result
['success', 'success', 'success']

Public API¶

class cl.loop.Loop(*futures, loop=None, return_exceptions=False)[source]¶

Asyncio Event loop context manager.

Context manager which get existing event loop or if none exist will create new one.

All coroutines are converted to task and scheduled to execute in near future. Scheduling is safe for long running tasks.

Example:

Create coroutine using @asyncio.coroutine decorator or with async/await syntax

>>> async def wait_for_it(timeout):
...    await asyncio.sleep(timeout)
...    return 'success sleep for {} seconds'.format(timeout)
...

Use context manager to get result from one or more coroutines

>>> with Loop(wait_for_it(5), wait_for_it(3), return_exceptions=True) as loop:
...    result = loop.run_until_complete()
...
>>> result
['success sleep for 3 seconds', 'success sleep for 5 seconds']

When single coroutine has been scheduled to run, only single value will be returned.

>>> with Loop(wait_for_it(4)) as loop:
...    result = loop.run_until_complete()
...
>>> result
'success sleep for 4 seconds'

Parameters:	futures (asyncio.Future, asyncio.coroutine) – One or more coroutine or future. loop (asyncio.AbstractEventLoop) – Optional existing loop. return_exceptions (Boolean) – If True will return exceptions as result. stop_when_done (Boolean) – If True will close the loop on context exit.

futures = None¶: Gathered futures.

static get_event_loop(loop: asyncio.events.AbstractEventLoop = None) → asyncio.events.AbstractEventLoop[source]¶

Get existing loop or create new one.

Parameters:	loop (asyncio.AbstractEventLoop) – Optional, already existing loop.
Returns:	Asyncio loop
Return type:	asyncio.AbstractEventLoop

gather(*futures: typing.Union[asyncio.futures.Future, <function coroutine at 0x7f323abcae18>])[source]¶

Gather list of futures/coros and return single Task ready to schedule.

Example:

Prepare all futures to execution

>>> async def do_something():
...    return 'something'
...
>>> async def do_something_else():
...    return 'something_else'
...

Gather all tasks and then pass to context loop

>>> loop = Loop(return_exceptions=True)
>>> loop.gather(do_something(), do_something_else())
>>> with loop as l:
...    result = l.run_until_complete()
...
>>> result
['something', 'something_else']

Parameters:	futures (asyncio.Future, asyncio.coroutine) – One or more coroutine or future.
Returns:	Futures grouped into single future
Return type:	asyncio.Task, asyncio.Future

run_until_complete()[source]¶

Run loop until all futures are done.

Order of result data will be the same as order of given coros.

Returns:	Result, list of results or None if task has been cancelled.
Return type:	None, list, Any

cancel()[source]¶

Cancel futures execution.

If futures are already done will return False, otherwise will return True

Returns:	Cancellation status.
Return type:	Boolean

Credits¶

Development¶

Paweł Zadrożny @pawelzny <pawel.zny@gmail.com>

Contributors¶

None yet. Why not be the first?

Read more how to contribute on Contributing.

Contributing¶

Contributions are welcome, and they are greatly appreciated! Every little bit helps, and credit will always be given.

You can contribute in many ways:

Types of Contributions¶

Report Bugs¶

Report bugs at https://github.com/pawelzny/context-loop/issues

If you are reporting a bug, please include:

Your operating system name and version.
Any details about your local setup that might be helpful in troubleshooting.
Detailed steps to reproduce the bug.

Fix Bugs¶

Look through the GitHub issues for bugs. Anything tagged with “bug” is open to whoever wants to implement it.

Implement Features¶

Look through the GitHub issues for features. Anything tagged with “feature” is open to whoever wants to implement it.

Write Documentation¶

authentication could always use more documentation, whether as part of the official authentication docs, in docstrings, or even on the web in blog posts, articles, and such.

Submit Feedback¶

The best way to send feedback is to file an issue at https://github.com/pawelzny/context-loop/issues

If you are proposing a feature:

Explain in detail how it would work.
Keep the scope as narrow as possible, to make it easier to implement.
Remember that this is a volunteer-driven project, and that contributions are welcome :)

Get Started!¶

Ready to contribute? Here’s how to set up context-loop for local development.

Fork the context-loop repo on GitHub.

Clone your fork locally:

$ git clone git@github.com:your_name_here/context-loop.git

3. Install your local copy into a virtualenv. Assuming you have PipEnv installed, this is how you set up your fork for local development:

$ cd context-loop/
$ make install-dev

Create a branch for local development:
```
$ git checkout -b name-of-your-bugfix-or-feature
```
Now you can make your changes locally.
When you’re done making changes, check that your changes pass flake8 and the tests, including testing other Python versions with tox:
```
$ make test-all
```
To get flake8 and tox, just pip install them into your virtualenv.

Commit your changes and push your branch to GitHub:

$ git add .
$ git commit -m "Your detailed description of your changes."
$ git push origin name-of-your-bugfix-or-feature

Submit a pull request through the GitHub website.

Pull Request Guidelines¶

Before you submit a pull request, check that it meets these guidelines:

The pull request should include tests.
If the pull request adds functionality, the docs should be updated. Put your new functionality into a function with a docstring, and add the feature to the list in README.rst.
The pull request should work for Python 3.4, 3.5, and 3.6, and for PyPy3. Check https://circleci.com/gh/pawelzny/context-loop and make sure that the tests pass for all supported Python versions.

LICENSE¶

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.