Manual Error Source Chaining and Formatting

use std::error::Error;
use std::fmt;
 
#[derive(Debug)]
pub enum PipelineError {
    ParseFailed(String),
    NetworkTimeout { target: String, cause: std::io::Error },
}
 
impl fmt::Display for PipelineError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::ParseFailed(msg) => write!(f, "Data parsing failure: {}", msg),
            Self::NetworkTimeout { target, .. } => write!(f, "Network request timed out for host: {}", target),
        }
    }
}
 
impl Error for PipelineError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        match self {
            Self::ParseFailed(_) => None,
            Self::NetworkTimeout { cause, .. } => Some(cause),
        }
    }
}