Function is_asyncio_reactor_installed

scrapy/utils/reactor.py:218–241

Check whether the installed reactor is :class:`~twisted.internet.asyncioreactor.AsyncioSelectorReactor`. Raise a :exc:`RuntimeError` if no reactor is installed. In a future Scrapy version, when Scrapy supports running without a Twisted reactor, this function won't be useful for checkin

()

def is_asyncio_reactor_installed() -> bool:
    """Check whether the installed reactor is :class:`~twisted.internet.asyncioreactor.AsyncioSelectorReactor`.

    Raise a :exc:`RuntimeError` if no reactor is installed.

    In a future Scrapy version, when Scrapy supports running without a Twisted
    reactor, this function won't be useful for checking if it's possible to use
    asyncio features, so the code that that doesn't directly require a Twisted
    reactor should use :func:`scrapy.utils.asyncio.is_asyncio_available`
    instead of this function.

    .. versionchanged:: 2.13
       In earlier Scrapy versions this function silently installed the default
       reactor if there was no reactor installed. Now it raises an exception to
       prevent silent problems in this case.
    """
    if not is_reactor_installed():
        raise RuntimeError(
            "is_asyncio_reactor_installed() called without an installed reactor."
        )

    from twisted.internet import reactor

    return isinstance(reactor, asyncioreactor.AsyncioSelectorReactor)