env_logger
log thường được sử dụng với env_logger để cấu hình logging
thông qua biến môi trường.
Mặc định, env_logger ghi log ra stderr.
File: Cargo.toml
[dependencies]
log = "0.4.0"
env_logger = "0.8.4"
Ví dụ:
File: src/main.rs
fn main() { env_logger::init(); info!("starting up"); error!("this is error!"); debug!("this is debug {}!", "message"); }
$ RUST_LOG=error cargo run
[2022-07-11T02:12:24Z ERROR main] this is error
$ RUST_LOG=info cargo run
[2022-07-11T02:12:24Z INFO main] starting up
[2022-07-11T02:12:24Z ERROR main] this is error
$ RUST_LOG=debug cargo run
[2022-07-11T02:12:24Z INFO main] starting up
[2022-07-11T02:12:24Z ERROR main] this is error
[2022-07-11T02:12:24Z DEBUG main] this is debug message!
Filter log theo module name:
$ RUST_LOG=main=info cargo run
[2022-07-11T02:12:24Z INFO main] starting up
[2022-07-11T02:12:24Z ERROR main] this is error
Hiện mọi log level cho module main:
$ RUST_LOG=main cargo run
[2022-07-11T02:12:24Z INFO main] starting up
[2022-07-11T02:12:24Z ERROR main] this is error
[2022-07-11T02:12:24Z DEBUG main] this is debug message!