.. _aiopg-run-loop:

Only use get_running_loop
=========================

Rationale
---------

:func:`asyncio.get_event_loop()` returns the
running loop :class:`asyncio.AbstractEventLoop` instead of **default**,
which may be different, e.g.

.. code-block:: py3

    loop = asyncio.new_event_loop()
    loop.run_until_complete(f())

.. note::

    :func:`asyncio.set_event_loop` was not called and default
    loop :class:`asyncio.AbstractEventLoop`
    is not equal to actually executed one.


Implementation
--------------

For the version below ``python3.7`` we added this implementation.

.. code-block:: py3

    if sys.version_info >= (3, 7, 0):
        __get_running_loop = asyncio.get_running_loop
    else:
        def __get_running_loop() -> asyncio.AbstractEventLoop:
            loop = asyncio.get_event_loop()
            if not loop.is_running():
                raise RuntimeError('no running event loop')
            return loop

This allows you to get a loop :class:`asyncio.AbstractEventLoop` correctly.