How to have retry decorator indicate used all retries?

I have implemented the retry decorator in my code, but would like to somehow indicate when it has used all of its retries. How can I do this?

I am using retrying decorator v1.3.3.

I tried using stop_func, but this seems to be called in nominal behaviour, not on a retry.

I am not sure how to call out the attempt number from the decorator.

from retrying import retry

def _query_with_retries(self):
    _retriable_query = retry(stop_max_attempt_number=3,
                             wait_incrementing_start=50,
                             wait_incrementing_increment=10)(self._query)
    return _retriable_query()

Currently, my code just throws a generic exception on the last retry. I would like to be able to message "all retries have been used up" or something like that.

Solution

You can catch the retrying.RetryError exception that is raised when the decorator stops retrying; do so in your own wrapper decorator:

from functools import wraps
from retrying import retry, RetryError

def printing_retry(*args, **kwargs):
    def decorator(f):            
        decorated = retry(*args, **kwargs)(f)
        @wraps(decorated)
        def wrapper(*args, **kwargs):
            try:
                return decorated(*args, **kwargs)
            except RetryError:
                print("All retries have been used up")
                # optionally, re-raise the exception at this point
                # raise
        return wrapper
    if len(args) == 1 and callable(args[0]):
        return decorator(args[0])
    return decorator

This decorator would replace the @retry decorators in your code; when you call a decorated function, it'll catch the RetryError exception that is raised when the function has run out of attempts, and print out a message instead.

Do remember to set wrap_exception=True if you want to wrap any exceptions raised during retrying in a RetryException exception.

Demo:

>>> @printing_retry(stop_max_attempt_number=1, wrap_exception=True)
... def do_something_unreliable():
...     if random.randint(0, 10) > 1:
...         raise IOError("Broken sauce, everything is hosed!!!111one")
...     else:
...         return "Awesome sauce!"
...
>>> do_something_unreliable()
All retries have been used up
>>> do_something_unreliable()
'Awesome sauce!'