hyperlight-host 0.1.0

/*
Copyright 2024 The Hyperlight Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

use prometheus::{register_histogram_with_registry, Histogram as PHistogram};
use tracing::{instrument, Span};

use super::{
    get_histogram_opts, get_metrics_registry, GetHyperlightMetric, HyperlightMetric,
    HyperlightMetricOps,
};
use crate::{new_error, HyperlightError, Result};

/// A named histogram
#[derive(Debug)]
pub struct Histogram {
    histogram: PHistogram,
    /// The name of the histogram
    pub name: &'static str,
}

impl Histogram {
    /// Creates a new histogram and registers it with the metric registry
    #[instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace")]
    pub fn new(name: &'static str, help: &str, buckets: Vec<f64>) -> Result<Self> {
        let registry = get_metrics_registry();
        let opts = get_histogram_opts(name, help, buckets);
        let histogram = register_histogram_with_registry!(opts, registry)?;
        Ok(Self { histogram, name })
    }
    /// Observes a value for a Histogram
    #[instrument(skip_all, parent = Span::current(), level= "Trace")]
    pub fn observe(&self, val: f64) {
        self.histogram.observe(val)
    }
    /// Gets the sum of values of an Histogram
    #[instrument(skip_all, parent = Span::current(), level= "Trace")]
    pub fn get_sample_sum(&self) -> f64 {
        self.histogram.get_sample_sum()
    }
    /// Gets the count of values of an Histogram
    #[instrument(skip_all, parent = Span::current(), level= "Trace")]
    pub fn get_sample_count(&self) -> u64 {
        self.histogram.get_sample_count()
    }
}

impl<S: HyperlightMetricOps> GetHyperlightMetric<Histogram> for S {
    #[instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace")]
    fn metric(&self) -> Result<&Histogram> {
        let metric = self.get_metric()?;
        <&HyperlightMetric as TryInto<&Histogram>>::try_into(metric)
    }
}

impl<'a> TryFrom<&'a HyperlightMetric> for &'a Histogram {
    type Error = HyperlightError;
    #[instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace")]
    fn try_from(metric: &'a HyperlightMetric) -> Result<Self> {
        match metric {
            HyperlightMetric::Histogram(histogram) => Ok(histogram),
            _ => Err(new_error!("metric is not a Histogram")),
        }
    }
}

impl From<Histogram> for HyperlightMetric {
    #[instrument(skip_all, parent = Span::current(), level= "Trace")]
    fn from(histogram: Histogram) -> Self {
        HyperlightMetric::Histogram(histogram)
    }
}

/// Observes a value for a Histogram
#[macro_export]
macro_rules! histogram_observe {
    ($metric:expr, $val:expr) => {{
        match $crate::metrics::GetHyperlightMetric::<$crate::metrics::Histogram>::metric($metric) {
            Ok(val) => {
                if let Err(e) = val.observe($val) {
                    log::error!("error calling observe with value {} on metric {} ", $val, e,)
                }
            }
            Err(e) => log::error!("error getting metric: {}", e),
        };
    }};
}

/// Gets the sum of values of an Histogram or logs an error if the metric is not found
/// Returns 0.0 if the metric is not found
#[macro_export]
macro_rules! histogram_sample_sum {
    ($metric:expr) => {{
        match $crate::metrics::GetHyperlightMetric::<$crate::metrics::Histogram>::metric($metric) {
            Ok(val) => match val.get_sample_sum() {
                Ok(val) => val,
                Err(e) => {
                    log::error!("error getting samples sum of metric {}", e,);
                    0.0
                }
            },

            Err(e) => {
                log::error!("error getting metric: {}", e);
                0.0
            }
        }
    }};
}

/// Gets the count of values of an Histogram or logs an error if the metric is not found
/// Returns 0 if the metric is not found
#[macro_export]
macro_rules! histogram_sample_count {
    ($metric:expr) => {{
        match $crate::metrics::GetHyperlightMetric::<$crate::metrics::Histogram>::metric($metric) {
            Ok(val) => match val.get_sample_count() {
                Ok(val) => val,
                Err(e) => {
                    log::error!("error getting samples count of metric {}", e,);
                    0
                }
            },

            Err(e) => {
                log::error!("error getting metric: {}", e);
                0
            }
        }
    }};
}
/// Observe the time it takes to execute an expression, record that time in microseconds in a Histogram and return the result of that expression
#[macro_export]
macro_rules! histogram_time_micros {
    ($metric:expr, $expr:expr) => {{
        let start = std::time::Instant::now();
        let result = $expr;
        histogram_observe!($metric, start.elapsed().as_micros() as f64);
        result
    }};
}