Will there be anything special needed to get ServiceStack to work with the new .NET Core 3.0 Worker Service and gRPC support? I’m envisioning using this in a self-hosted way with ServiceStack to get the benefits of being able to deploy this more easily as a Linux Deamon via Docker.
Yes that would be a big ticket item for after .NET Core 3.0 is officially released to integrate ServiceStack Services with gRPC.
In the meantime you would need to implement them independently, i.e. creating .NET Core gRPC Services as normal then you should be able to use the Service Gateway to call ServiceStack Services from inside your gRPC implementation.