Attribute Macro metered::metered

#[metered]

A procedural macro that generates a metric registry for an impl block.

use metered::{metered, Throughput, HitCount};

#[derive(Default, Debug)]
pub struct Biz {
    metrics: BizMetrics,
}

#[metered::metered(registry = BizMetrics)]
impl Biz {
    #[measure([HitCount, Throughput])]
    pub fn biz(&self) {        
        let delay = std::time::Duration::from_millis(rand::random::<u64>() % 200);
        std::thread::sleep(delay);
    }   
}

The metered attribute

#[metered(registry = YourRegistryName, registry_expr = self.wrapper.my_registry)]

registry is mandatory and must be a valid Rust ident.

registry_expr defaults to self.metrics, alternate values must be a valid Rust expression.

The measure attribute

Single metric:

#[measure(path::to::MyMetric<u64>)]

or:

#[measure(type = path::to::MyMetric<u64>)]

Multiple metrics:

#[measure([path::to::MyMetric<u64>, path::AnotherMetric])]

or

#[measure(type = [path::to::MyMetric<u64>, path::AnotherMetric])]

The type keyword is allowed because other keywords are planned for future extra attributes (e.g, instantation options).

When measure attribute is applied to an impl block, it applies for every method that has a measure attribute. If a method does not need extra measure infos, it is possible to annotate it with simply #[measure] and the impl block’s measure configuration will be applied.

The measure keyword can be added several times on an impl block or method, which will add to the list of metrics applied. Adding the same metric several time will lead in a name clash.