How to Add Custom CLI Flags/Options?

[h2cone]

In version 0.1, I implemented custom CLI flags/options by following this issue. However, in version 0.3, structopt has been replaced by clap. Is there a way to add custom flags or options in the new version as well?

[haoqixu]

pingora is using clap-3.x which also supports flatten:

use clap::Parser;

#[derive(Parser)]
struct MyOpt {
    #[clap(short)]
    something_cool: String,

    #[clap(flatten)]
    base_opts: Opt
}

fn main() {
    let my_opts = MyOpt::from_args();

    let mut my_server = Server::new(Some(my_opts.base_opts)).unwrap();

Run with -h flag and get:

load_balancer
Command-line options

USAGE:
    load_balancer [OPTIONS] -s <SOMETHING_COOL>

OPTIONS:
    -c, --conf <CONF>          The path to the configuration file.
    -d, --daemon               Whether this server should run in the background
    -h, --help                 Print help information
    -s <SOMETHING_COOL>
    -t, --test                 This flag is useful for upgrading service where the user wants to
                               make sure the new service can start before shutting down the old
                               server process.
    -u, --upgrade              This is the base set of command line arguments for a pingora-based
                               service

[h2cone]

Thank you for your answer, it was very helpful!