jdockerty/gruglb

A simple L4/L7 load balancer for grugs.

gruglb's Issues

Investigate `tokio` usage and `scoped` threads

The tokio ecosystem makes a lot of things simpler for async, even though this was avoided initially for this project (by using entirely std::thread and avoiding async calls. Now that it is in a good-state, I can expand into changing things around for tokio usage.

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Another area to investigate is scoped threads since all threads do not have their JoinHandle's managed, they is no call to .join() on their usage.

graceful shutdown

At the moment the application simply quits and will instantly sever connections.

The shutdown process should be handled gracefully.

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It looks like this should be easily achievable with a CancellationToken from tokio.

This might require a small amount of refactoring, but I envision a CancellationToken being passed as part of the Proxy trait, perhaps even held within self for the Tcp|HttpProxy.proxy(...) behaviour, rather than calling it from TcpProxy::proxy(...) instead?

Investigate lock-free/alternative to `Arc<Mutex<HashMap<T>>>`

I believe there are some "better" alternatives to using a Mutex around the std::collections::HashMap, this will need some testing/investigation though.

A quick cursory search leads to:

• https://github.com/xacrimon/dashmap
• https://github.com/saligrama/concache

Either of these could be useful in simplifying the locking of the HashMap for healthy targets.

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There has been an external recommendation on dashmap, but also consider using RwLock if I can deem that the number of updates comparative to reads is fairly small.

Expand error handling with `anyhow` and `thiserror`

At the moment, anyhow is being used as an easy way to use the ? operator from within functions, with relatively minimal error handling and customisation.

Expanding on this to return customised errors which are relevant to the flow would be hugely useful in debugging and also providing a .with_context(...) to what happened.

Implement a trait for common functionality

The accept_tcp and accept_http functions are very similar, their common use can be pulled into a trait and have both http/tcp satisfy the trait implementation.