But FWIW we totally agree with you. Finagle itself is a JVM library, and that worked well enough at Twitter [insert caveats here], but a big part of the reason we built linkerd is extending that model to non-JVM / polyglot services. There's SO much good stuff in Finagle... it would be a pity to confine it just to the JVM.
So far all our work has been JSON-over-HTTP, which is not performant. We've looked at gRPC and Thrift, but we've been dreading the prospect of having to pre-declare IDL, generate language glue and write client/server setup glue for every app.
At the moment, we're closing in on using NATS as a routing proxy, fulfilling a role very similar to Linkerd. Turns out it's fast enough that you can do RPC with it, and it seems very reliable. Language bindings are good to the point where you have to write almost no glue code. You have to pick a serialization format, and I think Msgpack might work well here.
