utils.py 文件源码

def requests_retry_session(
    retries=3,
    backoff_factor=0.3,
    status_forcelist=(500, 502, 504),
):
    """Opinionated wrapper that creates a requests session with a
    HTTPAdapter that sets up a Retry policy that includes connection
    retries.

    If you do the more naive retry by simply setting a number. E.g.::

        adapter = HTTPAdapter(max_retries=3)

    then it will raise immediately on any connection errors.
    Retrying on connection errors guards better on unpredictable networks.
    From http://docs.python-requests.org/en/master/api/?highlight=retries#requests.adapters.HTTPAdapter
    it says: "By default, Requests does not retry failed connections."

    The backoff_factor is documented here:
    https://urllib3.readthedocs.io/en/latest/reference/urllib3.util.html#urllib3.util.retry.Retry
    A default of retries=3 and backoff_factor=0.3 means it will sleep like::

        [0.3, 0.6, 1.2]
    """  # noqa
    session = requests.Session()
    retry = Retry(
        total=retries,
        read=retries,
        connect=retries,
        backoff_factor=backoff_factor,
        status_forcelist=status_forcelist,
    )
    adapter = HTTPAdapter(max_retries=retry)
    session.mount('http://', adapter)
    session.mount('https://', adapter)
    return session