[Core] Actor supports job lifetime about ray HOT 2 OPEN

We have a use case for this, where certain classes that facilitate running work on a cluster internally use actors for state management (as an implementation detail). It is possible that several of these classes are instantiated as part of the same job, and in this case, we want them to be using the same actor. We have been using named actors for this (not detached), and the classes have been constructing them passing a common name and with the get_if_exists=True flag set so they will be shared.

The change here makes the existing option less viable, as any classes that get an already-existing actor are only holding a weak reference to it, so if the original class that created it goes out of scope, the actor gets killed. Having an actor lifetime tied to the job/driver lifetime would be safer way to implement the original pattern.

from ray.

The use case sounds a bit narrow when applied in user-facing scenarios, can someone please provide some more use cases to when a job lifetime actor is very valuable?

from ray.