Move Logging Source Generator to MS.Extensions.Logging.Abstractions

[eerhardt]

Library authors today can use the LoggerMessage.Define APIs and log messages by only referencing Microsoft.Extensions.Logging.Abstractions.

However, in order to use the new Logging source generation feature, they now need to reference Microsoft.Extensions.Logging as well.

We should move the source generator and attribute to Microsoft.Extensions.Logging.Abstractions, so library authors don't need to change their references to use this new feature.

[ghost]

Tagging subscribers to this area: @maryamariyan
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Library authors today can use the LoggerMessage.Define APIs and log messages by only referencing Microsoft.Extensions.Logging.Abstractions.

However, in order to use the new Logging source generation feature, they now need to reference Microsoft.Extensions.Logging as well.

We should move the source generator and attribute to Microsoft.Extensions.Logging.Abstractions, so library authors don't need to change their references to use this new feature.

Author:	eerhardt
Assignees:	-
Labels:	area-Extensions-Logging
Milestone:	-

[maryamariyan]

@eerhardt OK to work on this without discussing over API review meetings?

[eerhardt]

If we have consensus with stakeholders, I think this could be an "email only" API review. None of the API shape would change, just which assembly it is contained in.

I guess I would get buy-off with all the stakeholders before working on it.

[davidfowl]

+1 on this moving

[ericstj]

Seems fine to me. Moving things is fine in previews without type-forwards. I don’t even think there is a case where folks would notice the move, since there is no scenario for runtime consumption nor design-time binary consumption of the type from it's old location.