Easily add --verbose and --quiet flags to CLIs using Clap.

$ cargo add clap-verbosity-flag

use clap::Parser;

#[derive(Debug, Parser)]
struct Cli {
    #[command(flatten)]
    verbosity: clap_verbosity_flag::Verbosity,
}

fn main() {
    let args = Cli::parse();
    env_logger::Builder::new()
        .filter_level(args.verbosity.into())
        .init();
    // Your code here
}

For tracing support, use the tracing feature:

$ cargo add clap-verbosity-flag --no-default-features --features tracing

use clap::Parser;

#[derive(Debug, Parser)]
struct Cli {
    #[command(flatten)]
    verbosity: clap_verbosity_flag::Verbosity,
}

fn main() {
    let args = Cli::parse();
    tracing_subscriber::fmt()
        .with_max_level(args.verbosity)
        .init();
    // Your code here
}

The default verbosity level will cause log / tracing to only report errors. The flags can be specified multiple times to increase or decrease the verbosity level. See the Documentation for info on how to change the default verbosity level.

• silence output: -q / --quiet
• show warnings: -v / --verbose
• show info: -vv / --verbose --verbose
• show debug: -vvv / --verbose --verbose --verbose
• show trace: -vvvv / --verbose --verbose --verbose --verbose

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/license/mit)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual-licensed as above, without any additional terms or conditions.