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

is not suitable. Also it's much faster than

asyncio.wait_for()

because

timeout

doesn't create a new task.

The

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

for skipping timeout functionality.

Alternatively,

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

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

if

inner()

execution is cancelled by timeout context manager.

If

call explicitly raises

TimeoutError

cm.expired

is

False

.

The scheduled deadline time is available as

property::

async with timeout(1.5) as cm: cm.deadline

Not finished yet timeout can be rescheduled 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

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.