Class _BackoffTimer

deepl/http_client.py:24–61

Implements exponential-backoff strategy. This strategy is based on the GRPC Connection Backoff Protocol: https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md

class _BackoffTimer:
    """Implements exponential-backoff strategy.
    This strategy is based on the GRPC Connection Backoff Protocol:
    https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md"""

    BACKOFF_INITIAL = 1.0
    BACKOFF_MAX = 120.0
    BACKOFF_JITTER = 0.23
    BACKOFF_MULTIPLIER = 1.6

    def __init__(self):
        self._num_retries = 0
        self._backoff = self.BACKOFF_INITIAL
        self._deadline = time.time() + self._backoff

    def get_num_retries(self):
        return self._num_retries

    def get_timeout(self):
        return max(self.get_time_until_deadline(), min_connection_timeout)

    def get_time_until_deadline(self):
        return max(self._deadline - time.time(), 0.0)

    def sleep_until_deadline(self):
        time.sleep(self.get_time_until_deadline())

        # Apply multiplier to current backoff time
        self._backoff = min(
            self._backoff * self.BACKOFF_MULTIPLIER, self.BACKOFF_MAX
        )

        # Get deadline by applying jitter as a proportion of backoff:
        # if jitter is 0.1, then multiply backoff by random value in [0.9, 1.1]
        self._deadline = time.time() + self._backoff * (
            1 + self.BACKOFF_JITTER * random.uniform(-1, 1)
        )
        self._num_retries += 1


class HttpClient: