Acknowledge order of webhook events

solidusio / solidus_stripe

💳 Integrate Solidus with Stripe

https://stripe.com

BSD 3-Clause "New" or "Revised" License

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Acknowledge order of webhook events #189

Open waiting-for-dev opened 1 year ago

waiting-for-dev commented 1 year ago

There's no guarantee that webhook events will arrive in the correct order. For instance, we could get authorization before a failure but be the reverse instead.

Partially replaces #160

loicginoux commented 1 year ago

the doc refering this https://stripe.com/docs/webhooks/best-practices#event-ordering the solution for this seems tricky. the event creation date (the event payload contains a created_at) is not a good source of truth. The last created is not necessarily the correct "final" state. A solution I have heard is to have internally a state machine of the object in relation to the event (an intent or a charge) that follow the state machine of the stripe object, and validate that a trnasition is possible given an event received... Not sure that this method covers all cases. I'll domore research on it in the next few days

waiting-for-dev commented 1 year ago

Thanks for your feedback, @loicginoux!

the event creation date (the event payload contains a created_at) is not a good source of truth. The last created is not necessarily the correct "final" state.

Hmm, are you sure? I understand that they're generated in order, but the delivery doesn't need to happen in that same order. From the docs:

Stripe does not guarantee delivery of events in the order in which they are generated.

Good point about maintaining an internal state machine.

loicginoux commented 1 year ago

I had a chat with a developer in the process of releasing Stripe payment for his company, he is more advanced in the implementation and gave us few technical advises after he had support from a Stripe Customer Solution Engineer. The Stripe team member advised him to do it this way. I still need to investigate more and we will definitely need to confirm that with Stripe support as well. I'll let you know when I have more information

waiting-for-dev commented 1 year ago

The solution here is not trivial and challenging to tackle without adding other infrastructure. An application should:

Receive the webhook.
Return a 200 to Stripe.
Validate the operation to perform (like the state machine proposed by @loicginoux, but we can also leverage the Solidus' state machine can_? methods).
If not possible, schedule for retry with whatever worker processor is used.

Like in https://github.com/solidusio/solidus_stripe/issues/188#issuecomment-1510855627, allowing applications to configure the adapter for Omnes subscribers would at least open gates for per-use-case implementations.