Last week, I wrote an analysis of the IETF Idempotency-Key specification. The specification aims to avoid duplicated requests. In short, the idea is for the client to send a unique key along with the request: If the server doesn’t know the key, it proceeds as usual and then stores the responseIf the server knows the key, it short-circuits any further processing and immediately returns the stored response This post shows how to implement it with Apache APISIX.

The first rule of distributed systems is 'Don’t distribute your system'. Designing distributed systems right is infamously hard for multiple reasons. The idempotency concept For example, a call to a function can succeed or fail in non-distributed systems. Once you move the called function to a remote component, a third option appears: you call the remote function but get no response from the component.