rootcause-backtrace

Stack backtrace support for the rootcause error reporting library.

Overview

This crate provides automatic stack trace capture for rootcause error reports. Backtraces help you see the call stack that led to an error, making debugging much easier.

Quick Start

Add to your Cargo.toml:

[dependencies]
rootcause = "0.11"
rootcause-backtrace = "0.11"

Automatic Capture (All Errors)

Install a hook to automatically attach backtraces to every error:

use rootcause::hooks::Hooks;
use rootcause_backtrace::BacktraceCollector;

fn main() {
    // Capture backtraces for all errors
    Hooks::new()
        .report_creation_hook(BacktraceCollector::new_from_env())
        .install()
        .expect("failed to install hooks");

    // Now all errors automatically include backtraces
    if let Err(e) = run_app() {
        eprintln!("{}", e);
    }
}

fn run_app() -> Result<(), rootcause::Report> {
    // Your application code
    # Ok(())
}

Manual Attachment (Specific Errors)

Use the extension trait to attach backtraces selectively:

use rootcause::{Report, report};
use rootcause_backtrace::BacktraceExt;

fn risky_operation() -> Result<(), Report> {
    Err(report!("operation failed"))
}

// Attach backtrace only to this specific error
let result = risky_operation().attach_backtrace();

Output Example

When an error with a backtrace is printed:

 ● Failed to process request
 ├ src/main.rs:45:10
 ├ Backtrace
 │ │ process_request - src/main.rs:45
 │ │ handle_connection - src/main.rs:32
 │ │ main             - src/main.rs:18
 │ │ note: 15 frame(s) omitted. For a complete backtrace, set RUST_BACKTRACE=full.
 │ ╰─
 │
 ● Database connection lost
 ╰ src/db.rs:89:5

Environment Variables

Control backtrace behavior at runtime:

RUST_BACKTRACE=full - Show all frames with full file paths (no filtering)
ROOTCAUSE_BACKTRACE - Comma-separated options:
- leafs - Only capture backtraces for leaf errors (errors without children)
- full_paths - Show full file paths instead of shortened versions

Examples:

# Show complete backtraces with all frames
RUST_BACKTRACE=full cargo run

# Only capture backtraces for leaf errors
ROOTCAUSE_BACKTRACE=leafs cargo run

# Show full file paths
ROOTCAUSE_BACKTRACE=full_paths cargo run

Filtering Frames

Customize which frames appear in backtraces:

use rootcause_backtrace::{BacktraceCollector, BacktraceFilter};

let collector = BacktraceCollector {
    filter: BacktraceFilter {
        // Skip these crates at the start of the backtrace
        skipped_initial_crates: &["rootcause", "rootcause-backtrace"],
        // Skip these crates in the middle
        skipped_middle_crates: &["tokio", "hyper"],
        // Skip these crates at the end
        skipped_final_crates: &["std"],
        // Limit to 15 frames
        max_entry_count: 15,
        // Show shortened paths (e.g., "src/main.rs" instead of "/home/user/project/src/main.rs")
        show_full_path: false,
    },
    // Only capture backtraces for leaf errors (errors without children)
    capture_backtrace_for_reports_with_children: false,
};

Release Builds

To get useful backtraces in release builds, enable debug symbols in your Cargo.toml:

[profile.release]
strip = false
debug = true  # or "line-tables-only" for smaller binaries

Path Privacy

By default, backtraces show shortened paths for better readability, but they may still expose your filesystem structure. If this is a concern, use rustc's path remapping:

# Set when building for release
export RUSTFLAGS="--remap-path-prefix=$HOME=/home/user --remap-path-prefix=$PWD=/build"
cargo build --release

This remaps absolute paths to generic placeholders.

Features

Smart filtering - Automatically hides noisy runtime frames while showing your code
Readable output - Shortened paths and formatted display
Configurable - Control capture behavior and filtering per your needs
Environment-aware - Respects RUST_BACKTRACE and custom options
Opt-in by design - Only applications that install the hooks pay the capture cost

rootcause-backtrace 0.11.0