erract - Structured Error Handling for Rust

erract provides production-ready error handling that solves real problems:

• Actionable errors: Categorized by what callers can do (retry, fail, etc.)
• Explicit retry semantics: No guessing from error messages
• Rich context: Automatic location capture with zero overhead
• Type safety: Enforce context at module boundaries

Philosophy

Two audiences, two needs:

• Machines: Need flat structures, clear error kinds, predictable codes
• Humans: Need rich context, call paths, business-level information

This library combines the best ideas from:

• Apache OpenDAL's error design
• The exn crate
• Years of production error handling experience

Quick Start

use erract::prelude::*;

fn process_user(id: u32) -> erract::Result<String> {
    let error = || Error::permanent(
        ErrorKind::NotFound,
        format!("user not found: {}", id),
    );

    lookup_user(id)
        .or_raise(error)?
        .ok_or_else(|| {
            Error::permanent(
                ErrorKind::NotFound,
                "user not found".to_string(),
            ).raise()
        })
}

fn lookup_user(id: u32) -> erract::Result<Option<String>> {
    Ok(None)
}

Features

• Zero runtime overhead: Uses #[track_caller] instead of expensive backtraces
• Domain-specific errors: HTTP, Database, and Storage error kinds
• Error trees: Support for multiple concurrent failures
• Type safety: Compiler enforces context at module boundaries

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.