How to Use env_logger in Rust

Crates/Env Logger

2026-04-17T12:05:42+00:00

Initialize env_logger in Rust by adding the dependency, calling env_logger::init(), and setting the RUST_LOG environment variable.

Add env_logger to your dependencies and initialize it in main before any logging calls to configure output via environment variables.

use log::*;

fn main() {
    env_logger::init();
    info!("Hello, world!");
}

Add this to your Cargo.toml:

[dependencies]
env_logger = "0.9.3"
log = "0.4.20"

Set the RUST_LOG environment variable to control verbosity, for example: RUST_LOG=info cargo run.