Choose RPC framework

[haircommander]

there are tons of RPC frameworks to choose from. we've flirted with the idea of grpc, ttrpc, cap n proto. we should probably just pick one. any other ideas?

[saschagrunert]

I think tonic via unix domain sockets and golang GRPC is still broken due to hyperium/h2#487, but we have to give it a try.

[mrunalp]

One worry I have is about the binary size and the memory usage. I opened a PR #4 to set some flags during build time. I think if we stay under 4MB RSS that may be okay if we run one conmon for a pod.

[rphillips]

I took a look at the server and see it using 3.0 MB RSS in release mode. Removing Tonic decreases RSS to 1 MB (still using tokio). Perhaps it does make sense to find something lighter weight.

[saschagrunert]

I was playing around with cap'n proto and indeed it seems to use less memory. But switching to the single threaded grpc (tonic) variant saves even more memory: #9

[saschagrunert]

I think we can close this one now and stick with tonic. I'll add a CI job to compare the used RSS of PRs.