decorate

decorate is used to modify or wrap an object which is already configured in another Provider.

Provider object has also a .decorate method with the same logic.

If you want to apply decorator pattern and do not want to alter existing provide method, then it is a place for decorate. It will construct object using earlier defined provider and then pass it to your decorator before returning from the container.

from dishka import decorate, Provider

class MyProvider(Provider):
    @decorate
    def decorate_a(self, a: A) -> A:
        return ADecorator(a)

Such decorator function can also have additional parameters.

from dishka import decorate, Provider

class MyProvider(Provider):
    @decorate
    def decorate_a(self, a: A, b: B) -> A:
        return ADecorator(a)

The limitation is that you cannot use decorate in the same provider as you declare factory or alias for dependency. But you won’t need it because you can update the factory code.

The idea of decorate is to postprocess dependencies provided by some external source, when you combine multiple Provider objects into one container