Add a new property to the `listen` task to determine what it should return

[fjtirado]

What would you like to be added?

Depending on the scenario, users might want to keep CloudEvent attributes in the workflow model or just the CloudEvent data

Proposal(s):

After discussing alternatives, we agree that a new property called return should be added to Listen task. Possible values are: data (default), envelope (whole cloud event), raw (for future use on binary events)

Alternative(s):

Include always the whole CloudEvent and, if user only wants data, include the proper expression in output

Additional info:

No response

Community Notes

• Please vote by adding a 👍 reaction to the feature to help us prioritize.
• If you are interested to work on this feature, please leave a comment.

[JBBianchi]

Maybe I'm missing something, and sorry if I do, but I would assume one would want the whole event, and if one wants only the data property, they can select it using output.as. Is it really necessary to introduce a new concept altogether ?

[fjtirado]

Maybe I'm missing something, and sorry if I do, but I would assume one would want the whole event, and if one wants only the data property, they can select it using output.as. Is it really necessary to introduce a new concept altogether ?

Sure, I found always including the whole cloud event (which includes id and specversion, which are hardly meaningful) will pollute the workflow model. I feel the most frequent use case is users not being interested on any of the CE attributes, just the data and therefore, we will forcing them to write output.as: .data most of the time, which is pretty verbose. I base that assumption on the fact that I have not seen a workflow definition for 0.8 which uses the flag to include the whole CE (it is true that these deinitions lacks correlation support at all, which is the scenarion in which you probably want to keep some of the CloudEvent attributes, For those cases, you have to use the new keyword plus probably an output or context filter to store them in the proper place)