Source code for airflow.providers.amazon.aws.executors.utils.exponential_backoff_retry
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from __future__ import annotations
import logging
from datetime import datetime, timedelta
from typing import Callable
from airflow.utils import timezone
[docs]log = logging.getLogger(__name__)
[docs]def calculate_next_attempt_delay(
attempt_number: int,
max_delay: int = 60 * 2,
exponent_base: int = 4,
) -> timedelta:
"""
Calculate the exponential backoff (in seconds) until the next attempt.
:param attempt_number: Number of attempts since last success.
:param max_delay: Maximum delay in seconds between retries. Default 120.
:param exponent_base: Exponent base to calculate delay. Default 4.
"""
return timedelta(seconds=min((exponent_base**attempt_number), max_delay))
[docs]def exponential_backoff_retry(
last_attempt_time: datetime,
attempts_since_last_successful: int,
callable_function: Callable,
max_delay: int = 60 * 2,
max_attempts: int = -1,
exponent_base: int = 4,
) -> None:
"""
Retry a callable function with exponential backoff between attempts if it raises an exception.
:param last_attempt_time: Timestamp of last attempt call.
:param attempts_since_last_successful: Number of attempts since last success.
:param callable_function: Callable function that will be called if enough time has passed.
:param max_delay: Maximum delay in seconds between retries. Default 120.
:param max_attempts: Maximum number of attempts before giving up. Default -1 (no limit).
:param exponent_base: Exponent base to calculate delay. Default 4.
"""
if max_attempts != -1 and attempts_since_last_successful >= max_attempts:
log.error("Max attempts reached. Exiting.")
return
next_retry_time = last_attempt_time + calculate_next_attempt_delay(
attempt_number=attempts_since_last_successful, max_delay=max_delay, exponent_base=exponent_base
)
current_time = timezone.utcnow()
if current_time >= next_retry_time:
try:
callable_function()
except Exception:
log.exception("Error calling %r", callable_function.__name__)
next_delay = calculate_next_attempt_delay(
attempts_since_last_successful + 1, max_delay, exponent_base
)
log.info("Waiting for %s seconds before retrying.", next_delay)