如何在 Rust 上记录所有内容或如何记录多个内容？

Question

I couldn't find easy information about how to log properly on Rust. I'm doing like this:

use log::{debug, error, info, warn};

fn main() {
    env_logger::init();
    info!("test info");
    error!("test error");
}

How do I activate both info and error?

RUST_LOG="info,error" cargo run

won't activate both (none of them get activated), but

RUST_LOG="info" cargo run

works.

Also, how to activate everything?

Answer 1

The log levels are hierarchical, meaning that if you set the level to info , info messages and all levels above it will be captured. Only messages with a lower priority than the enabled level are filtered out:

• error
• warn
• info
• debug
• trace

Being the lowest level, trace will capture all logs:

RUST_LOG="trace" cargo run