[−][src]Crate tracing_error

Utilities for enriching error handling with tracing diagnostic information.

Overview

tracing is a framework for instrumenting Rust programs to collect scoped, structured, and async-aware diagnostics. This crate provides integrations between tracing instrumentation and Rust error handling. It enables enriching error types with diagnostic information from tracing span contexts, formatting those contexts when errors are displayed, and automatically generate tracing [events] when errors occur.

The crate provides the following:

SpanTrace, a captured trace of the current tracing span context
ErrorLayer, a subscriber layer which enables capturing SpanTraces

Note: This crate is currently experimental.

Compiler support: requires rustc 1.39+

Usage

Currently, tracing-error provides the SpanTrace type, which captures the current tracing span context when it is constructed and allows it to be displayed at a later time.

This crate does not currently provide any actual error types implementing std::error::Error. Instead, user-constructed errors or libraries implementing error types may capture a SpanTrace and include it as part of their error types.

For example:

use std::{fmt, error::Error};
use tracing_error::SpanTrace;

#[derive(Debug)]
pub struct MyError {
    context: SpanTrace,
    // ...
}

impl fmt::Display for MyError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // ... format other parts of the error ...

        self.context.fmt(f)?;

        // ... format other error context information, cause chain, etc ...
    }
}

impl Error for MyError {}

impl MyError {
    pub fn new() -> Self {
        Self {
            context: SpanTrace::capture(),
            // ... other error information ...
        }
    }
}

In the future, this crate may also provide its own Error types as well, for users who do not wish to use other error-handling libraries.

Applications that wish to use tracing-error-enabled errors should construct an ErrorLayer and add it to their [Subscriber] in order to enable capturing SpanTraces. For example:

use tracing_error::ErrorLayer;
use tracing_subscriber::prelude::*;

fn main() {
    let subscriber = tracing_subscriber::Registry::default()
        // any number of other subscriber layers may be added before or
        // after the `ErrorLayer`...
        .with(ErrorLayer::default());

    // set the subscriber as the default for the application
    tracing::subscriber::set_global_default(subscriber);
}

Structs

ErrorLayer	A subscriber `Layer` that enables capturing `SpanTrace`s.
SpanTrace	A captured trace of `tracing` spans.