# Copyright 2016 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

import logging
import time

logger = logging.getLogger(__name__)


def retry_on_exception(func, max_retries, exception_types, backoff_func=lambda n: 0):
    """Retry a callable against a set of exceptions, optionally sleeping between retries.

    :param callable func: The callable to retry.
    :param int max_retries: The maximum number of times to attempt running the function.
    :param tuple exception_types: The types of exceptions to catch for retry.
    :param callable backoff_func: A callable that will be called with the current attempt count to
                                  determine the amount of time to sleep between retries. E.g. a
                                  max_retries=4 with a backoff_func=lambda n: n * n will result in
                                  sleeps of [1, 4, 9] between retries. Defaults to no backoff.
    """
    for i in range(0, max_retries):
        if i:
            time.sleep(backoff_func(i))
        try:
            return func()
        except exception_types as e:
            logger.debug(f"encountered exception on retry #{i}: {e!r}")
            if i == max_retries - 1:
                raise