sheen ✨

A polished, colorful logging library for Rust ✨

Inspiration

sheen is inspired by charmbracelet/log, the excellent Go logging library. We wanted to bring the same polished experience to Rust.

Features

• Colorful, human-readable output
• Structured key=value logging
• Multiple formatters: Text, JSON, Logfmt
• Sub-loggers with persistent fields
• TTY detection (auto-disables colors when piped)
• Builder pattern configuration
• Zero config defaults
• log crate compatibility (optional feature flag)
• tracing crate compatibility (optional feature flag)

Installation

[dependencies]
sheen = "0.3"

With log crate support:

[dependencies]
sheen = { version = "0.3", features = ["log"] }

With tracing crate support:

[dependencies]
sheen = { version = "0.3", features = ["tracing"] }

Quick Start

fn main() {
    sheen::init();

    sheen::info!("Server started", port = 3000);
    sheen::debug!("Loading config");
    sheen::warn!("Cache miss", key = "user_123");
    sheen::error!("Connection failed", attempts = 3);
}

Output:

14:32:15 INFO  Server started port=3000
14:32:15 WARN  Cache miss key="user_123"
14:32:15 ERROR Connection failed attempts=3

Custom Configuration

use sheen::{Logger, Level};

fn main() {
    sheen::init_with(
        Logger::new()
            .level(Level::Trace)
            .prefix("myapp")
            .timestamp(true)
    );

    sheen::trace!("verbose output");
    sheen::info!("ready");
}

Sub-loggers

Create loggers with persistent fields using .with():

use sheen::{Logger, Level};

let logger = Logger::new().level(Level::Debug);
let req_log = logger.with(&[("request_id", &"abc123")]);

req_log.info("started", &[]);
req_log.info("db query", &[("table", &"users")]);
req_log.info("completed", &[("status", &200)]);

Output:

14:32:15 INFO  started request_id="abc123"
14:32:15 INFO  db query request_id="abc123" table="users"
14:32:15 INFO  completed request_id="abc123" status=200

Log Crate Integration

Enable the log feature to use sheen as a backend for the log crate. This captures logs from any dependency that uses log::info!(), log::warn!(), etc.

use sheen::{Logger, Level};

fn main() {
    Logger::new()
        .level(Level::Debug)
        .init()
        .unwrap();

    // Standard log macros now go through sheen
    log::info!("server started");
    log::warn!("cache nearly full");
}

Tracing Crate Integration

Enable the tracing feature to use sheen as a subscriber for the tracing crate. This captures events from any dependency that uses tracing::info!(), tracing::warn!(), etc.

use sheen::{Logger, Level, SheenLayer};

fn main() {
    SheenLayer::new(Logger::new().level(Level::Trace)).init();

    tracing::info!("server started");
    tracing::warn!("cache nearly full");
}

Formatters

Text (default)

Colorful, human-readable output:

let logger = Logger::new();
logger.info("hello", &[("port", &3000)]);
// 14:32:15 INFO  hello port=3000

JSON

Structured output for log aggregators:

use sheen::{Logger, JsonFormatter};

let logger = Logger::new().formatter(JsonFormatter);
logger.info("hello", &[("port", &3000)]);
// {"level":"info","msg":"hello","time":"14:32:15","port":3000}

Logfmt

Key=value format for Heroku, Splunk, etc:

use sheen::{Logger, LogfmtFormatter};

let logger = Logger::new().formatter(LogfmtFormatter);
logger.info("hello", &[("port", &3000)]);
// level=info msg="hello" time="14:32:15" port=3000

TTY Detection

Colors are automatically disabled when output is piped:

# Colors enabled
cargo run

# Colors disabled (piped to file)
cargo run 2> logs.txt

Force colors on or off:

let logger = Logger::new().colorize(false);

License

MIT