How to wrap a library written in another language

You can try using a pool of instances of that library, for example, with GitHub - dashbitco/nimble_pool: A tiny resource-pool implementation for Elixir · GitHub, it might help (or not) with parallelism.

Would it be possible to multiplex multiple calls through single port? HTTP/2 is pretty much doing the same.

I’ve used ZeroMQ to communicate between two different processes written in different languages with pretty good results. They have libraries for many languages, and I think there’s a community driven one for Elixir (haven’t tested it).

From their docs:

ZeroMQ (also spelled ØMQ, 0MQ or ZMQ) is a high-performance asynchronous messaging library, aimed at use in distributed or concurrent applications. It provides a message queue, but unlike message-oriented middleware, a ZeroMQ system can run without a dedicated message broker.

ZeroMQ supports common messaging patterns (pub/sub, request/reply, client/server and others) over a variety of transports (TCP, in-process, inter-process, multicast, WebSocket and more), making inter-process messaging as simple as inter-thread messaging. This keeps your code clear, modular and extremely easy to scale.

Thanks for all the suggestions. I am planning to use plain GenServer + Port for now, it is the path with least resistance. Parallelism can be achieved by multiplexing the port and embedding a sequence number to match responses back to the requests.