dipstick/src/multi.rs

//! Dispatch metrics to multiple sinks.

use crate::attributes::{Attributes, MetricId, OnFlush, Prefixed, WithAttributes};
use crate::input::{Input, InputDyn, InputKind, InputMetric, InputScope};
use crate::name::MetricName;
use crate::Flush;

use std::sync::Arc;
use std::io;

/// Opens multiple scopes at a time from just as many outputs.
#[derive(Clone, Default)]
pub struct MultiInput {
    attributes: Attributes,
    inputs: Vec<Arc<dyn InputDyn + Send + Sync>>,
}

impl Input for MultiInput {
    type SCOPE = MultiInputScope;

    fn metrics(&self) -> Self::SCOPE {
        #[allow(clippy::redundant_closure)]
        let scopes = self.inputs.iter().map(|input| input.input_dyn()).collect();
        MultiInputScope {
            attributes: self.attributes.clone(),
            scopes,
        }
    }
}

impl MultiInput {
    /// Create a new multi-input dispatcher.
    #[deprecated(since = "0.7.2", note = "Use new()")]
    pub fn input() -> Self {
        Self::new()
    }

    /// Create a new multi-input dispatcher.
    pub fn new() -> Self {
        Self::default()
    }

    /// Returns a clone of the dispatch with the new target added to the list.
    pub fn add_target<OUT: Input + Send + Sync + 'static>(&self, out: OUT) -> Self {
        let mut cloned = self.clone();
        cloned.inputs.push(Arc::new(out));
        cloned
    }
}

impl WithAttributes for MultiInput {
    fn get_attributes(&self) -> &Attributes {
        &self.attributes
    }
    fn mut_attributes(&mut self) -> &mut Attributes {
        &mut self.attributes
    }
}

/// Dispatch metric values to a list of scopes.
#[derive(Clone, Default)]
pub struct MultiInputScope {
    attributes: Attributes,
    scopes: Vec<Arc<dyn InputScope + Send + Sync>>,
}

impl MultiInputScope {
    /// Create a new multi scope dispatcher with no scopes.
    pub fn new() -> Self {
        MultiInputScope {
            attributes: Attributes::default(),
            scopes: vec![],
        }
    }

    /// Add a target to the dispatch list.
    /// Returns a clone of the original object.
    pub fn add_target<IN: InputScope + Send + Sync + 'static>(&self, scope: IN) -> Self {
        let mut cloned = self.clone();
        cloned.scopes.push(Arc::new(scope));
        cloned
    }
}

impl InputScope for MultiInputScope {
    fn new_metric(&self, name: MetricName, kind: InputKind) -> InputMetric {
        let name = &self.prefix_append(name);
        let metrics: Vec<InputMetric> = self
            .scopes
            .iter()
            .map(move |scope| scope.new_metric(name.clone(), kind))
            .collect();
        InputMetric::new(
            MetricId::forge("multi", name.clone()),
            move |value, labels| {
                for metric in &metrics {
                    metric.write(value, labels.clone())
                }
            },
        )
    }
}

impl Flush for MultiInputScope {
    fn flush(&self) -> io::Result<()> {
        self.notify_flush_listeners();
        for w in &self.scopes {
            w.flush()?;
        }
        Ok(())
    }
}

impl WithAttributes for MultiInputScope {
    fn get_attributes(&self) -> &Attributes {
        &self.attributes
    }
    fn mut_attributes(&mut self) -> &mut Attributes {
        &mut self.attributes
    }
}