Generic Axum Error Handler

app_error.rs

use axum::{
    http::StatusCode,
    response::{IntoResponse, Response},
};
use std::{fmt, panic::Location};

// Make our own error that wraps all errors
pub struct AppError {
    inner: Box<dyn std::error::Error>,
    location: &'static Location<'static>,
}

impl fmt::Display for AppError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "AppError at {}: {}", self.location, self.inner)
    }
}

impl fmt::Debug for AppError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self)
    }
}

// Tell axum how to convert `AppError` into a response.
impl IntoResponse for AppError {
    fn into_response(self) -> Response {
        log::error!("{}", self);
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            format!("Something went wrong: {}", self.inner),
        )
            .into_response()
    }
}

// This enables using `?` on functions that return `Result<_, Error>` to turn them into
// `Result<_, AppError>`. That way you don't need to do that manually.
impl<E> From<E> for AppError
where
    E: Into<Box<dyn std::error::Error>>,
{
    #[track_caller]
    fn from(err: E) -> Self {
        Self {
            inner: err.into(),
            location: Location::caller(),
        }
    }
}