Can we choose the output format of the cloudevent from the broker ?

[Smixi]

Hi,

I'm starting experimenting with Knative, and familiarize with Cloudevents.
I'm currently pushing events to the broker events using the Cloudevent Python SDK using the JSON format.
I connected a service through a trigger, but I was surprised to receive them as CloudEvents using HTTP binding protocol. Can we specify what format we want from the broker ? As I am in dev mode, i'm using the default In memory broker.

Thanks in advance :).

[evankanderson]

I believe the current configuration always uses the HTTP binary encoding (with CloudEvents as headers). I suspect there are efficiency reasons for doing so -- is there a particular reason for preferring one over the other in your use case?

[Smixi]

In my case, I'm using a FastAPI stack, with endpoints for each events, and thus I'm able to validate that the receive object is conform before attempting to treat it thanks to Pydantic. The issue I had is that in my local environment (without Knative), everything was working fine, so I was able to send event in JSON CloudEvent format, receive and validate them on the server. The issue arise that I was no more working with the broker, and couldn't figure out why. Of course, conversion meant that my service was now refusing the HTTP Binary protocol.
It just felt weird that sending JSON events means not receiving them as JSON later on (but it also makes sense that the broker could transform the data), I don't think it is/was documented somewhere which default the broker is using.

Anyway, I ended using a special library that parses Cloudevent as binary:

https://github.com/Smixi/knative_journey/blob/2fac98938bce0c9835ecf4d0d59d8125583e1ebe/mail-service/app/mail_router.py#L13

Recap:
No, but because I was sending them as JSON, I was expecting to receive them as JSON. For me, it's easier to debug/interpret as human during the dev phase. I guess services shouldn't care which format is send, and handle both through an intermediate middleware.