week46.md

2024-11-14

We created a design document conforming to project description.

Some thoughts and ideas by yours truly (Lauri) (written while others are busy writing the design document):

• We could do integration testing by mocking TcpStream
  • Server logic needs to be generic, T: Read + Write + ...
• We should do unit testing
• Automatic test coverage generation would be interesting but not required
• The actual protocol definition will just be some Rust structs and enums, decorated with serde macros
• In a release version, the server-server protocol should probably have a version field... This can be done with an enum if we want to

2024-11-15

We broke ground and wrote first code for the server node, including configuration file parsing and server peer listener thread. It was mostly straightforward, but joining threads had us thinking for a while.

What we learned, was that Rust's thread JoinHandle's join-method returns a Result, whose:

• Ok-variant contains the return value from the function/closure which the thread ran
  • This could be a nested Result<T, E>!
• Err-variant contains the value passed to panic (usually a string reference)
  • But it's provided to us through a Box<dyn Any + Send + 'static>>-pointer!
  • This is because panic!(...) doesn't have to be called with a &str, some applications need a different type to return from a paniced thread
  • But in our case it's going to be a &str if anything, so we call downcast_ref::<&str>() on it to get an Option<&str> that can be debug-printed

The session itself was conducted on Discord with voice communication and a desktop share stream. This seems to work pretty well.