Django storage class instantiated every time

[cristianocca]

https://github.com/jazzband/sorl-thumbnail/blob/master/sorl/thumbnail/default.py#L24

Is it needed that the storage class is created every time it's needed? What happens if the storage class has a slow constructor? This happens with a custom AWS S3 storage class, that will check for the bucket on class construction only.

[cristianocca]

Sorry, it seems the culprit is here, when rendering images:

https://github.com/jazzband/sorl-thumbnail/blob/master/sorl/thumbnail/images.py#L40

[bartels]

This appears to be the same bug as #301

It's particularly bad with the latest boto3 storage from django-storages, as it adds a large delay for each thumbnail generated.

It looks to be due to the behavior of instantiating a new storage instance for each thumbnail when deserializing from the cache. What would fix it is having some module level variable to cache the storage instances. That way only a single storage instance would be initialized for each storage type.

[claudep]

Duplicate of #301