[FEEDBACK] What about rich models?

[FabioRodrigues]

I've seen you based this project on DDD, I'd like to ask you what is the guidance about rich models (entities)? Shouldn't the services just orchestrate the calls? Like calling many services, external infra actions, etc? For example:

Given I want to reserve a book
When I reserve one book
And there is at least one available book
Then The available quantity of this book should be decreased by one
And I must receive an email informing I reserved it

#book_service.py
@atomic
def reserve_book(self, id: int, user_id: int) -> None:
    user = User.objects.get(id=user_id)

    book = Book.objects.get(id=id)
    book.reserve(user.email)
    book.save()

    email_client.send(user.name, user.email, "book reserved")

#models/book.py
def reserve(self, user_email: string):
    if(self.available_quantity ==  0):
        raise Exception("book not available")

    self.availabe_quantity -= 1
    self.renting_history.append(user_email, datetime.today())

[FabioRodrigues]

hey @phalt anything about this? Thx!

[phalt]

I don't know how I missed this question, apologises.

Personally (emphasis - my personal opinion) I'd have the reserve method on the service layer, and not the model layer. This would make the Model a thin model.