celery retry_task decorator. Depends on django transaction.

gistfile1.txt

def retry_task(name, max_retries=3, ignore_result=True, queue="celery", countdown=10, exceptions=[]):
    """
        This decorator allows you to retry a celery task if it raised an exception of type defined in <exceptions>.
        Tasks are also wrapped by a commit_on_success decorator to avoid incomplete data in the database.

         arguments are :
            name:   The name of the task
            max_retries: The number of retries before giving up [default: 3]
            ignore_result: Should celery ignores the result [default: True]
            queue: The queue name [default: "celery"]
            countdown: The ellapsed time between retries [default: 10 seconds]
            exceptions [mandatory]: An array of exception type.If an exception of those type is raised, we will retry the task, any other exception will be raise automatically.

    """
    if not exceptions:
        raise ValueError("You must define a list of retriable exceptions.")
    def decorator(func):
        @task(name=name, max_retries=max_retries, ignore_result=ignore_result, queue=queue)
        @transaction.commit_on_success
        def wrapper(*args, **kwargs):
            try:
                return func(*args, **kwargs)
            except Exception as exc:
                for exception_type in exceptions:
                    if isinstance(exc, exception_type): #This mean we should retry
                        return wrapper.retry(countdown=countdown, exc=exc)
                raise #This is an unexception error, we should not retry


        return wrapper

    return decorator