twisted.py 文件源码

def gen_retries(start, end, intervals, clock=reactor):
    """Helper for retrying something, sleeping between attempts.

    Yields ``(elapsed, remaining, wait)`` tuples, giving times in seconds. The
    last item, `wait`, is the suggested amount of time to sleep before trying
    again.

    This function works in concert with `retries`. It's split out so that
    `retries` can capture the correct start time rather than the time at which
    it is first iterated.

    :param start: The start time, in seconds, of this generator. This must be
        congruent with the `IReactorTime` argument passed to this generator.
    :param end: The desired end time, in seconds, of this generator. This must
        be congruent with the `IReactorTime` argument passed to this
        generator.
    :param intervals: A iterable of intervals, each in seconds, which should
        be used as hints for the `wait` value that's generated.
    :param clock: An optional `IReactorTime` provider. Defaults to the
        installed reactor.

    """
    for interval in intervals:
        now = clock.seconds()
        if now < end:
            wait = min(interval, end - now)
            yield now - start, end - now, wait
        else:
            yield now - start, end - now, 0
            break