measure_relay.py

def chunk_duration(session, url, chunk_length=1048576):
    """Check when a request stabilizes."""
    response = session.get(url, stream=True, verify=False)
    # length = int(response.headers['Content-Length'])
    durations = []
    chunk_count = 1
    chunks = response.iter_content(chunk_length)
    start_time = time.monotonic()
    # discard first chunk
    next(chunks)
    end_time = time.monotonic()
    duration = end_time - start_time
    durations.append(duration)
    for content in chunks:
        # response.read(chunk_length)
        end_time = time.monotonic()
        duration = end_time - start_time
        # keeping just for all the play below
        chunk_count += 1
        delta_duration = abs(durations[-1] - duration)
        start_time = end_time
        durations.append(duration)
        # Less than 5 milliseconds of duration differnce on downloading the
        # same amount of bytes
        if delta_duration < 0.008:
            break
    # take 1 more chunk
    end_time = time.monotonic()
    duration = end_time - start_time
    # keeping to check how much durations changed
    durations.append(duration)
    chunk_count += 1
    # and return the median of the last 3
    bytes = chunk_length * 3
    duration = sum(durations[-3:])
    return (durations, bytes, duration)