How can I deserialize a datetime string in celery?

Question

I have a celery task function which takes as attribute a datetime object. Inside the celery task however this object is a string. I imagine this is serialization at work.

How do I perform deserialization on the other end? Do I have to handle it on my own or is there a more elegant way to do it that's built in in celery?

# tasks.py
@shared_task
def my_func(start_time, end_time):
  print(type(start_time)) # unicode, need datetime


# calling file
my_func.delay(datetime.now()-timedelta(hours=1), datetime.now())

Answer 1

You can try using another serializer. You are presumably using the default json serializer, which means datetimes must be represented as strings. The other supported serializers should be able to handle datetimes.

http://docs.celeryproject.org/en/latest/userguide/calling.html#serializers

# calling file
my_func.apply_async(
    args=[datetime.now()-timedelta(hours=1), datetime.now()], 
    serializer='pickle',  # or 'yaml' or 'msgpack' 
)

We can't use the celery shortcut function delay if we want to pass execution options, so we use the underlying apply_async instead.