Crate function_timer

This crate allow to put a time attribut macro on any function or impl block. It will time the execution of functions and emit a histogram metric using metrics crate.

In case the annotation is on an impl block :

• all method will be timed
• there will be a tag struct with the struct name.
• all time annotations on any method will override the one on impl block.
• it’s possible to disable specific methods using #[time(disable)].

Note that #[time(disable)] can’t be on an impl block.

Example

• On functions and methods :

use std::error::Error;
use metrics_exporter_prometheus::PrometheusBuilder;
use function_timer::time;

struct Test {}

impl Test {
    #[time("my_metric")]
    pub fn impl_function(&self) {
        println!("This another test");
    }

    #[time("another_metric")]
    pub fn impl_fail_function(&self, text:&str) -> Result<(), Box<dyn Error>>{
        let number:usize = text.parse()?;
        println!("{number}");

        Ok(())
    }

    #[time("my_metric")]
    pub fn static_function() {
        println!("This another test");
    }
}

#[time("my_metric")]
pub fn free_function() {
    println!("This a test");
}

fn main() -> Result<(), Box<dyn Error>> {
    let builder = PrometheusBuilder::new();
    let handle = builder.install_recorder()?;

    free_function();

    Test::static_function();

    let t = Test {};
    t.impl_function();

    let result = t.impl_fail_function("azerty");
    assert!(result.is_err());
    let result = t.impl_fail_function("1");
    assert!(result.is_ok());


    println!("{}", handle.render());

    Ok(())
}

• on impl block :

use std::error::Error;
use metrics_exporter_prometheus::PrometheusBuilder;
use function_timer::time;

struct Test {}

#[time("my_metric")]
impl Test {
    #[time("override_my_metric")]
    pub fn impl_function(&self) {
        println!("This another test");
    }

    pub fn impl_fail_function(&self, text:&str) -> Result<(), Box<dyn Error>>{
        let number:usize = text.parse()?;
        println!("{number}");

        Ok(())
    }

    pub fn static_function() {
        println!("This another test");
    }
}

fn main() -> Result<(), Box<dyn Error>> {
    let builder = PrometheusBuilder::new();
    let handle = builder.install_recorder()?;

    Test::static_function();

    let t = Test {};
    t.impl_function();

    let result = t.impl_fail_function("azerty");
    assert!(result.is_err());
    let result = t.impl_fail_function("1");
    assert!(result.is_ok());


    println!("{}", handle.render());

    Ok(())
}

Structs

• FunctionTimer
  Timer.

Attribute Macros

• time
  Macro that time a function and emit a histogram metric using metrics crate