Operator API

[Spikhalskiy]

No description provided.

[alexshtin]

Most of the handler code is copied from AdminHandler, right? And you gonna keep it there for some period of time. It would be great to reduce code duplication and have an instance of OpearatorHandler in AdminHandeler and call these 3 methods from it. With proper comment that it is deprecated and so on.

[Spikhalskiy]

@alexshtin I would generally agree with you about code duplication if there are two different active endpoints that are using the same code.
But here the situation is a bit different, we will have a deprecated and a new version of the endpoints and none of them by themselves is a superset. And we actually will not need to keep the old endpoint updated with the new functionality.
I think we should go copy-paste route in this situation because it will SIMPLIFY support and REDUCE the burden. Your approach while having a good intention to dedup the code will likely bring more complexity and potential mistakes.

The way you propose to directly use operator_handler in admin_handler will not fly, because operator_handler doesn't provide a superset of operations/return values, the endpoints are slightly different. For example, the new operator endpoint doesn't return some of the data that is returned by the deprecated version (GetSearchAttributesResponse#runId as an example).
Striving to remove code duplication here will have to create of a shared manager that is used by old and new endpoints sets and provides a superset of functionality.

This way, every time we will be editing the new version of the code you will have to worry about not breaking and supporting the code paths used by the deprecated version. Compare it with the current approach, where we will be just directly editing the new endpoints and can forget about updating the old ones.
If we dedup way, we also can't just remove the deprecated endpoints in the future. We will need to 1. remove unused functionality from the shared code 2. move the shared code to the operator handler.

[alexshtin]

I would agree on this. Let's leave two copies.