Rust at the boundary

A small example of using types to make invalid runtime configuration harder to express.

15 August 20261 min readRust · Engineering Notes

Note / example: the code below illustrates a boundary; it is not production benchmark data.

Rust is especially useful where configuration turns into a resource.

fn bounded_timeout(seconds: f64) -> Result<std::time::Duration, &'static str> {
    if !seconds.is_finite() || seconds <= 0.0 {
        return Err("timeout must be positive and finite");
    }
    std::time::Duration::try_from_secs_f64(seconds).map_err(|_| "timeout is out of range")
}

The fallible conversion keeps the failure close to the transport boundary.