FaaS - Incoming span kind

[RohitRanjanMS]

The convention indicates that, based on the faas.trigger, it should adhere to the corresponding semantic convention but the faas span semantic requires that for an incoming span, the span kind must be set as Server.

For incoming FaaS spans, the span kind MUST be Server.

Although Server is suitable for HTTP scenarios, it lacks relevance for scenarios such as PubSub and Timer. Is there a specific rationale for setting Server regardless of the faas.trigger, or can we define a more appropriate kind for each scenario?

[RohitRanjanMS]

@lmolkova FYI

[pyohannes]

This depends on whether one has different spans for modelling the incoming FaaS operations and for the operation of consuming a message.

If there are different spans for those two operations, then it's fine that the FaaS span is of kind SERVER (as the additional messaging span will have the kind CONSUMER).

If there's only one span used, it should be CONSUMER.

This relates to #652.

[RohitRanjanMS]

@jviau FYI

[RohitRanjanMS]

Thanks @pyohannes for the additional context, I will follow #652

[AlexanderWert]

If there are different spans for those two operations, then it's fine that the FaaS span is of kind SERVER (as the additional messaging span will have the kind CONSUMER).

If there's only one span used, it should be CONSUMER.

Would be good to add this logic to the FaaS Semantic Conventions, to make it explicit.

[joaopgrassi]

@RohitRanjanMS would you like to submit a PR to add this clarification? OR should we close this all in favor of #652?