errlog is a simple log library based on anyhow, it wraps file name and line number for your error message.
Add the errlog dependencies into your Cargo.toml, then import errlog macro
use errlog::{elog, AnyContext, AnyResult};
Now you can use it in function that return AnyResult<xxx> such as
return Err(elog!("Unkown file type"));
or
File:open(filepath).context(elog!("Cannot open file {}", filepath))?;