[dugmartin]

Except in the microservice approach with multiple servers you have introduced the possibility of network partitioning where microservice A can't reach microservice B. Unless your language/runtime model can deal with that you have hidden that error case in your abstraction. I think a lot of microservice architectures are implemented with the YOLO model where there is no thought to network errors and all calls are assumed to succeed.

Language/runtimes like Erlang & Elixir on the BEAM/OTP that were built with this in mind work well. They are completely functional with all state contained with lightweight processes and can send messages with timeout handling transparently across nodes in a cluster. With OTP you get a supervision tree for those processes that can automatically restart nodes and child processes of nodes.