refactor: Derive Clone for RustLogFilter and Directive

[pol-epsevg]

I was writing something using logforth, and instead of using different filters for different appenders (Like in the example from percas), I wanted to reuse a single filter:

let filter = RustLogFilterBuilder::try_from_spec(&configuration.filter)?.build();

let mut builder = logforth::starter_log::builder();

// If configured, add an opentelemetry exporter to the logger
if let Some(otlp_config) = &configuration.opentelemetry {
    let appender = {
        let exporter = LogExporter::builder()
            .with_tonic()
            .with_endpoint(&otlp_config.endpoint)
            .with_protocol(Protocol::Grpc)
            .build()?;

        OpentelemetryLogBuilder::new(otlp_config.service_name.clone(), exporter)
            .label("service.name", otlp_config.service_name.clone())
            .build()
    };

    // First filter use
    builder = builder.dispatch(|b| b.filter(filter).append(appender));
};

// If enabled, also log to stderr
if configuration.stderr {
    builder = builder.dispatch(|b| {
        // Can't use that same filter a second time!
        b.filter(filter)
            .append(Stderr::default().with_layout(TextLayout::default()))
    });
}

My obvious next step is to .clone() the filter, but turns out that isn't implemented. Is there any particluar reason? Am I missing something?

[tisonkun]

Reasonable. Thanks!

[pol-epsevg]

Thanks tison, appreciated.

[tisonkun]

I'm going to review the other PR and do some API changes to release a new version next week.

Feel free to ping me if I miss this schedule.

I hope a logforth-core 0.5 would be a candidate for logforth-core 1.0.

If you're interested, feel free to drop your ideas on #225 and #205