Updated StripeModel._api_update() to use Idempotency Key object

The _api_update() method now does the following:

1) Generates a new Idempotency Key object if not given one using the
   Stripe object's ID that is being updated.
2) Uses the Idempotency key (from 1)) to make the Stripe API call.
3) Updates the metadata of the Stripe object with the idempotency_key
   key if the Stripe object supports the metadata key.

djstripe/models/base.py

@@ -301,6 +301,16 @@ def _api_update(
  if not stripe_account:
  stripe_account = self._get_stripe_account_id(api_key)
 
+ kwargs, idempotency_key = self.__class__.add_idempotency_key_to_metadata(
+ action="update",
+ idempotency_key=idempotency_key,
+ stripe_obj_id=self.id,
+ **kwargs,
+ )
+
+ # Remove stripe_obj_id if it exists
+ kwargs.pop("stripe_obj_id", None)
+
  return self.stripe_class.modify(
  self.id,
  api_key=api_key,

docs/history/2_8_0.md

@@ -21,6 +21,7 @@
 - `stripe.api_version` is no longer manipulated by dj-stripe.
 - Resolved ambiguity between `LineItem` and `InvoiceItem` models. It was incorrectly assumed that the `lines` List object on `Invoice` and `UpcomingInvoice` models only return `InvoiceItem` objects. Moreover `LineItem` objects can also be of type `subscription` if the user adds a Subscription to their `Invoice` as a lineitem.
 - Added support for `idempotency` keys. `djstripe` now automatically generates and puts keys in Stripe Object's Metadata (if possible). Users have the option to supply their own as well for `create` calls.
+- Added support for `idempotency` keys for `update` calls. `djstripe` now automatically generates and puts keys in Stripe Object's Metadata (if possible). Users have the option to supply their own as well for `create` calls.
 
 ## Deprecated features