50 lines
1.5 KiB
Python
50 lines
1.5 KiB
Python
import time
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import random
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from datetime import datetime
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from exceptions import TimeoutException
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DEFAULT_RETRY_TIMEOUT = 60
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def qps_retry(f):
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def wrapped_f(*args, **kw):
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return QPSService().call(f, *args, **kw)
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return wrapped_f
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class QPSService:
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def __init__(self, queries_per_second=10,
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retry_timeout=DEFAULT_RETRY_TIMEOUT):
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self._queries_per_second = queries_per_second
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self._retry_timeout = retry_timeout
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def call(self, fn, *args, **kwargs):
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start_time = datetime.now()
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attempt_number = 1
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while True:
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try:
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return fn(*args, **kwargs)
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except Exception as e:
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response = getattr(e, 'response', None)
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if response and (response.status_code == 429):
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self.retry(start_time, attempt_number)
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else:
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raise e
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attempt_number += 1
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def retry(self, first_request_time, retry_count):
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elapsed = datetime.now() - first_request_time
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if elapsed.seconds > self._retry_timeout:
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raise TimeoutException()
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# inverse qps * (1.5 ^ i) is an increased sleep time of 1.5x per
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# iteration.
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delay = (1.0/self._queries_per_second) * 1.5 ** retry_count
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# https://www.awsarchitectureblog.com/2015/03/backoff.html
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# https://github.com/googlemaps/google-maps-services-python/blob/master/googlemaps/client.py#L193
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sleep_time = delay * (random.random() + 0.5)
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time.sleep(sleep_time)
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