Struct RuntimeMonitor

pub struct RuntimeMonitor { /* private fields */ }

Available on tokio_unstable and crate feature rt only.

Monitors key metrics of the tokio runtime.

Usage

use std::time::Duration;
use tokio_metrics::RuntimeMonitor;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
    let handle = tokio::runtime::Handle::current();

    // print runtime metrics every 500ms
    {
        let runtime_monitor = RuntimeMonitor::new(&handle);
        tokio::spawn(async move {
            for interval in runtime_monitor.intervals() {
                // pretty-print the metric interval
                println!("{:?}", interval);
                // wait 500ms
                tokio::time::sleep(Duration::from_millis(500)).await;
            }
        });
    }

    // await some tasks
    tokio::join![
        do_work(),
        do_work(),
        do_work(),
    ];

    Ok(())
}

async fn do_work() {
    for _ in 0..25 {
        tokio::task::yield_now().await;
        tokio::time::sleep(Duration::from_millis(100)).await;
    }
}

Implementations

impl RuntimeMonitor

pub fn new(runtime: &Handle) -> RuntimeMonitor

Creates a new RuntimeMonitor.

pub fn intervals(&self) -> RuntimeIntervals

Produces an unending iterator of RuntimeMetrics.

Each sampling interval is defined by the time elapsed between advancements of the iterator produced by RuntimeMonitor::intervals. The item type of this iterator is RuntimeMetrics, which is a bundle of runtime metrics that describe only changes occurring within that sampling interval.

Example

use std::time::Duration;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
    let handle = tokio::runtime::Handle::current();
    // construct the runtime metrics monitor
    let runtime_monitor = tokio_metrics::RuntimeMonitor::new(&handle);

    // print runtime metrics every 500ms
    {
        tokio::spawn(async move {
            for interval in runtime_monitor.intervals() {
                // pretty-print the metric interval
                println!("{:?}", interval);
                // wait 500ms
                tokio::time::sleep(Duration::from_millis(500)).await;
            }
        });
    }

    // await some tasks
    tokio::join![
        do_work(),
        do_work(),
        do_work(),
    ];

    Ok(())
}

async fn do_work() {
    for _ in 0..25 {
        tokio::task::yield_now().await;
        tokio::time::sleep(Duration::from_millis(100)).await;
    }
}

Trait Implementations

impl Debug for RuntimeMonitor

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.