Invalid Kafka Binary event when content-type not provided

[shnplr]

The Kafka spec states in section 3: If the content-type header is not present then the receiver uses structured mode with the JSON event format.

Since the SDK allows a binary message with data to be generated without providing dataContentType, the assumption here is that consumers MUST assume this is a Structured event (even though its not).

Question

1. Should the spec be amended to allow receivers to detect content mode whenever content-type does not start with application/cloudevents.
2. Alternatively should the serialize SDK generate an error for Binary mode with data and no content-type?

[slinkydeveloper]

If the content-type header is not present then the receiver uses structured mode with the JSON event format.

TBH I don't recall this particular sentence, but looking at it, it seems to me there are two conflicting sentences https://github.com/cloudevents/spec/blob/v1.0.1/kafka-protocol-binding.md#3-kafka-message-mapping:

The receiver of the event can distinguish between the two content modes by inspecting the content-type Header of the Kafka message. If the header is present and its value is prefixed with the CloudEvents media type application/cloudevents, indicating the use of a known event format, the receiver uses structured mode, otherwise it defaults to binary mode.

And then:

If the content-type header is not present then the receiver uses structured mode with the JSON event format.

I'm gonna open an issue in the spec repo

[shnplr]

I assume in the first paragraph, the key sentence is "If the header is present..."
But I agree the wording could be improved to avoid any suggested contradiction.

[slinkydeveloper]

@shnplr I've opened an issue cloudevents/spec#812 and proposed 2 solutions, feel free to provide your input there.

[slinkydeveloper]

The conflicting sentence was removed from the spec: slinkydeveloper/spec@c023f5c

I'm going to close this issue because I think it's solved now, reopen if you need it.