Question

I want to use get_or_insert, But how do I know that it’s just created or fetched from existing entries.

Answer 1

In a nutshell, you can’t. get_or_insert is just a convenience function, though, and one you can write and improve for yourself quite easily. Here’s a simple replacement that returns a tuple, indicating if it was created or not:

@classmethod
def my_get_or_insert(cls, key_name, parent=None, **kwargs):
  def _tx():
    entity = cls.get_by_key_name(key_name, parent=parent)
    if entity:
      return entity, False
    entity = cls(key_name=key_name, parent=parent, **kwargs)
    entity.put()
    return entity, True
  return db.run_in_transaction(_tx)

And here’s how you’d use it:

entity, created = MyKind.my_get_or_insert('foo', bar=123)
if created:
  # Do whatever you do with a new entity here.

Just bear in mind that if you use it with the recipe above, anything you do based on whether the entity is new or not is not transactional – your code could fail after creating the entity but before doing that. If what you want to do has side-effects, you should probably do it inside the transaction.