Vince Varga vincevarga.dev

Rust Error Handling Patterns

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Category: Tutorials

⚠️ PLACEHOLDER CONTENT: This is a fake blog post with dummy content for demonstration purposes only.

The ? Operator

Rust’s ? operator makes error propagation elegant:

use std::fs::File;
use std::io::{self, Read};

fn read_config() -> io::Result<String> {
    let mut file = File::open("config.toml")?;
    let mut contents = String::new();
    file.read_to_string(&mut contents)?;
    Ok(contents)
}

Custom Error Types

Define your own errors with thiserror:

use thiserror::Error;

#[derive(Error, Debug)]
pub enum AppError {
    #[error("Configuration file not found")]
    ConfigNotFound,
    
    #[error("Invalid data: {0}")]
    InvalidData(String),
    
    #[error("IO error: {0}")]
    Io(#[from] std::io::Error),
}

fn load_config() -> Result<Config, AppError> {
    let data = std::fs::read_to_string("config.toml")
        .map_err(|_| AppError::ConfigNotFound)?;
    
    parse_config(&data)
        .ok_or_else(|| AppError::InvalidData("malformed TOML".into()))
}

The anyhow Crate

For applications (not libraries), anyhow simplifies everything:

use anyhow::{Context, Result};

fn main() -> Result<()> {
    let config = load_config()
        .context("Failed to load application config")?;
    
    run_app(config)?;
    Ok(())
}

This post is placeholder content and does not represent real technical advice.

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