A bit of hacking around on wrapping Cloudflare's quiche QUIC stack with nim.
Not yet functional - do not use!
This is me trying to learn nim, really. I got interested in it recently, specifically in the context of networking, as in libp2p.
There's a whole thing already underway to get QUIC working in nim called nim-quic, which is much more mature than this thing is likely to ever get. So if you're looking for QUIC in nim and found this repo, you probably want nim-quic instead.
This repo is me getting my hands dirty with nim in a real world context that I know well enough to feel fairly at home in, but not so well that it's boring.
Since this is about me personally learning nim, what am I actually trying to accomplish here?
Concretely, my first target is porting the example client from rust / c to nim, using the wrapper in src/quichenim.
On a more meta level, arriving at that goal requires a few things:
- learn nim and nimble well enough to get started
- play with quiche a bit and learn about the C FFI interface
- figure out how to wrap a C API in nim
- I decided on futhark on the basis that it was the first thing I tried that worked.
- [-] wrap the generated API to make it all nice like
- still figuring out "idiomatic" nim, so this needs work still
- recently found a good style guide, will dig in soon
- [-] dig into nim's
asyncdispatchandasycnetmodules- currently using asyncdispatch directly since its APIs expose
ptr SockAddrand friends that quiche wants - also it looks like it will give me more control over the event loop if needed
- currently using asyncdispatch directly since its APIs expose
So far, I've only tested this with nix using the flake.nix in this repo. It should also work with other package managers, provided you have a recent rust toolchain, clang, and nim and friends.
If you are using nix, you can nix develop in this repo, or use direnv with echo 'use flake' > .envrc followed by direnv allow.
Once that's all good, you should be able to run nimble build --debug which will also build quiche on the first run and copy the library and header files to where the ffi code expects them.
By default, the build statically links to libquiche.a, which kind of sucks cause the hello world binary is 15MB. If you set -d:quichenim.UseDynamicLinking it will link dynamically instead, but I had to mess about with symlinks and DYLD_FALLBACK_LIBRARY_PATH to get it to run and I haven't bothered automating that yet.
The quichenim binary that gets built by nimble build is a work-in-progress port of the client in vendor/quiche/quiche/examples.
With the example server running on, e.g. 127.0.0.1:4567, you can run the client with:
./quichenim http://127.0.0.1:4567/
It should print some logs at you and eventually print the response from the example server (byez)
- clean up and refactor things
- add tests & wire up valgrind to make sure we're not leaking stuff
- think more about high-level API design