Comment by lajr
10 months ago
This looks promising! One of the important aspects of protocol buffers, avro etc is how they deal with evolving schemas and backwards/forward compatibility. I don't see anything in the docs addressing that. Is it possible for old services to handle new payloads / new services to handle old payloads or do senders and receivers need to be rewritten each time the schema changes?
Good question! Compared to Protocol Buffers and Apache Avro, that each have their own specialised schema languages created by them, for them, JSON BinPack taps into the popular and industry-standard JSON Schema language.
That means that you can use any tooling/approach from the wide JSON Schema ecosystem to manage schema evolution. A popular one from the decentralised systems world is Cambria (https://www.inkandswitch.com/cambria/).
That said, I do recognise that schema evolution tech in the JSON Schema world is not as great as it should be. I'm a TSC member of JSON Schema and a few of us are definitely thinking hard on this problem too and trying to make it even better that the competition.
A lot of people already think about this problem with respect to API compatibility for REST services using the OpenAPI spec for example. It's possible to have a JSON Schema which is backwards compatible with previous versions. I'm not sure how backwards-compatible the resulting JSON BinPack schemas are however.
Great seeing you over here Michael :) For other people reading this thread, Michael and I are collaborating on a paper covering the schema compiler I've been working on for JSON BinPack. Funny coincidence!