Unhandled webhooks can receive 200 responses, earlier logging and returning errors might help

[nicdwilson]

Describe the Bug

In several investigations, we have seen that merchants can show 200 responses to webhooks in their merchant dashboards, but these failed to create scheduled actions for asynchronous handling in Action Scheduler.

Event EV0676G554YSA2 which would have marked a submitted order as confirmed and moved the order from on-hold to processing is one such example.

Clearly this is difficult to reproduce, not neccesarily a bug and very dependent on the environment. Potentially though, logging the received webhook before attempting to set up the async handler, and possibly logging failures to create that handler, and returning error codes, will go a long way to making troubleshooting a little easier :)

[sverleis]

Affected ticket(s): 9372251-zen

[nicdwilson]

Noting that an error response may prompt a webhook retry from GoCardless, which is what we want if the async handler is not successfully set up.