log-once

Collection of helper macros for logging some events only once.

This crate provide macro in the log_once family (warn_once!, trace_once!, ...); that only send a logging event once for every message. It rely and uses the logging infrastructure in the log crate; and is fully compatible with any logger implementation.

These macro will store the already seen messages in a BTreeSet, and check if a message is in the set before sending the log event.

Examples

```rust

[macro_use]

extern crate log;

[macro_use]

extern crate log_once;

pub fn shavetheyak(yaks: &[Yak]) { for yak in yaks { info!(target: "yak_events", "Commencing yak shaving for {:?}", yak);

    loop {
        match find_a_razor() {
            Ok(razor) => {
                // This will only appear once in the logger output for each razor
                info_once!("Razor located: {}", razor);
                yak.shave(razor);
                break;
            }
            Err(err) => {
                // This will only appear once in the logger output for each error
                warn_once!("Unable to locate a razor: {}, retrying", err);
            }
        }
    }
}

} ```

License

log-once is distributed under the terms of both the MIT license and the Apache License (Version 2.0).

See LICENSE-APACHE and LICENSE-MIT for details.