Failed events are not enhanced with extension attributes

[egorlepa]

Describe the bug
Failed events are not enhanced with extension attributes prior to forwarding to the deadLetterSink as described here:
https://knative.dev/docs/eventing/event-delivery/#configuring-channel-event-delivery
(knativeerrordest, knativeerrorcode, knativeerrordata)

Expected behavior
I expect failed events to be enhanced with extension attributes.

Knative release version
1.5

Additional context
Sending event to deadLetterSink is kind of pointless without some context (where this event was meant to be delivered; what happened). There is not really much i can do with such event - i don't know which subscriber failed to consume it and why

[pierDipi]

Hi @egorlepa, thanks for reporting!

I agree that we should add this feature to this implementation but I'm not entirely sure about the knativeerrordata, the body might be very large and it might not fit into a header.

I'll discuss this with the group (you're very welcome to join) because I don't think the data can be included in this way.

[egorlepa]

hey, @pierDipi i believe default channel implementation can be used as a reference. it defines max body size as 1024 bytes, everything else gets truncated.
https://github.com/knative/eventing/blob/release-1.5/pkg/channel/attributes/knative_error.go

[egorlepa]

Please, consider also adding information about sender (broker name/channel name/something like that). I am trying to create a single entry point for failed events and such information would help.

[pierDipi]

Hi @egorlepa, yes, I agree these are valuable attributes for debugging dead letter sinks, do you have the capacity to contribute this feature?

I'm available if you have any questions on the inner workings of the project and its components, or if you need guidance on the implementation.

[egorlepa]

@pierDipi can't see why not, how may i contact you?

[pierDipi]

you can reach out to us with these methods https://knative.dev/docs/community/contributing/#learn-and-connect or just with comments on this issue if you don't want to create accounts or join groups, etc.

We also run a meeting, Eventing Kafka WG, on Tuesday every other week, you can find it in this shared calendar https://calendar.google.com/calendar/u/0/embed?src=knative.team_9q83bg07qs5b9rrslp5jor4l6s@group.calendar.google.com&ctz=America/Los_Angeles

[matzew]

@egorlepa Are you interested in tackling this?

You can reach us on the resources that Pierangelo mentioned 😄

[egorlepa]

Yeah, sorry, last 2 weeks were very tough. I'll have time this week, also I joined slack