https://github.com/aio-libs/async-timeout

asyncio-compatible timeout class
https://github.com/aio-libs/async-timeout

asyncio

Last synced: 3 months ago
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asyncio-compatible timeout class

• Host: GitHub
• URL: https://github.com/aio-libs/async-timeout
• Owner: aio-libs
• License: other
• Created: 2016-09-08T12:57:19.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2024-03-04T02:54:53.000Z (4 months ago)
• Last Synced: 2024-03-09T14:34:53.763Z (3 months ago)
• Topics: asyncio
• Language: Python
• Size: 240 KB
• Stars: 535
• Watchers: 19
• Forks: 59
• Open Issues: 13
• Metadata Files:
  • Readme: README.rst
  • Changelog: CHANGES.rst
  • License: LICENSE

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• awesome-stars - aio-libs/async-timeout - asyncio-compatible timeout class (Python)
• my-awesome - aio-libs/async-timeout - asyncio-compatible timeout class (Python)
• my-stars - aio-libs/async-timeout - asyncio-compatible timeout class (Python)

README

        
async-timeout

=============

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asyncio-compatible timeout context manager.

Usage example

-------------

The context manager is useful in cases when you want to apply timeout

logic around block of code or in cases when ``asyncio.wait_for()`` is

not suitable. Also it's much faster than ``asyncio.wait_for()``

because ``timeout`` doesn't create a new task.

The ``timeout(delay, *, loop=None)`` call returns a context manager

that cancels a block on *timeout* expiring::

   from async_timeout import timeout

   async with timeout(1.5):

       await inner()

1. If ``inner()`` is executed faster than in ``1.5`` seconds nothing

   happens.

2. Otherwise ``inner()`` is cancelled internally by sending

   ``asyncio.CancelledError`` into but ``asyncio.TimeoutError`` is

   raised outside of context manager scope.

*timeout* parameter could be ``None`` for skipping timeout functionality.

Alternatively, ``timeout_at(when)`` can be used for scheduling

at the absolute time::

   loop = asyncio.get_event_loop()

   now = loop.time()

   async with timeout_at(now + 1.5):

       await inner()

Please note: it is not POSIX time but a time with

undefined starting base, e.g. the time of the system power on.

Context manager has ``.expired`` property for check if timeout happens

exactly in context manager::

   async with timeout(1.5) as cm:

       await inner()

   print(cm.expired)

The property is ``True`` if ``inner()`` execution is cancelled by

timeout context manager.

If ``inner()`` call explicitly raises ``TimeoutError`` ``cm.expired``

is ``False``.

The scheduled deadline time is available as ``.deadline`` property::

   async with timeout(1.5) as cm:

       cm.deadline

Not finished yet timeout can be rescheduled by ``shift_by()``

or ``shift_to()`` methods::

   async with timeout(1.5) as cm:

       cm.shift(1)  # add another second on waiting

       cm.update(loop.time() + 5)  # reschedule to now+5 seconds

Rescheduling is forbidden if the timeout is expired or after exit from ``async with``

code block.

Installation

------------

::

   $ pip install async-timeout

The library is Python 3 only!

Authors and License

-------------------

The module is written by Andrew Svetlov.

It's *Apache 2* licensed and freely available.