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use core::attributes::{Buffered, Attributes, WithAttributes, Prefixed};
use core::name::MetricName;
use core::{Flush, MetricValue};
use core::input::InputKind;
use core::metrics;
use core::output::{Output, OutputScope, OutputMetric};
use core::error;
use queue::queue_out;
use cache::cache_out;
use core::label::Labels;
use std::rc::Rc;
use std::cell::{RefCell, RefMut};
#[derive(Clone, Debug)]
pub struct Prometheus {
attributes: Attributes,
push_url: String,
}
impl Output for Prometheus {
type SCOPE = PrometheusScope;
fn output(&self) -> Self::SCOPE {
PrometheusScope {
attributes: self.attributes.clone(),
buffer: Rc::new(RefCell::new(String::new())),
push_url: self.push_url.clone(),
}
}
}
impl Prometheus {
pub fn push_to(url: &str) -> error::Result<Prometheus> {
debug!("Pushing to Prometheus {:?}", url);
Ok(Prometheus {
attributes: Attributes::default(),
push_url: url.to_string(),
})
}
}
impl WithAttributes for Prometheus {
fn get_attributes(&self) -> &Attributes { &self.attributes }
fn mut_attributes(&mut self) -> &mut Attributes { &mut self.attributes }
}
impl Buffered for Prometheus {}
#[derive(Debug, Clone)]
pub struct PrometheusScope {
attributes: Attributes,
buffer: Rc<RefCell<String>>,
push_url: String,
}
impl OutputScope for PrometheusScope {
fn new_metric(&self, name: MetricName, kind: InputKind) -> OutputMetric {
let prefix = self.prefix_prepend(name).join("_");
let scale = match kind {
InputKind::Timer => 1000,
_ => 1,
};
let cloned = self.clone();
let metric = PrometheusMetric { prefix, scale };
OutputMetric::new(move |value, labels| {
cloned.print(&metric, value, labels);
})
}
}
impl Flush for PrometheusScope {
fn flush(&self) -> error::Result<()> {
let buf = self.buffer.borrow_mut();
self.flush_inner(buf)
}
}
impl PrometheusScope {
fn print(&self, metric: &PrometheusMetric, value: MetricValue, labels: Labels) {
let scaled_value = value / metric.scale;
let value_str = scaled_value.to_string();
let mut strbuf = String::new();
strbuf.push_str(&metric.prefix);
let labels_map = labels.into_map();
if !labels_map.is_empty() {
strbuf.push('{');
let mut i = labels_map.into_iter();
let mut next = i.next();
while let Some((k, v)) = next {
strbuf.push_str(&k);
strbuf.push_str("=\"");
strbuf.push_str(&v);
next = i.next();
if next.is_some() {
strbuf.push_str("\",");
} else {
strbuf.push('"');
}
}
strbuf.push_str("} ");
} else {
strbuf.push(' ');
}
strbuf.push_str(&value_str);
let buffer = self.buffer.borrow_mut();
if strbuf.len() + buffer.len() > BUFFER_FLUSH_THRESHOLD {
metrics::PROMETHEUS_OVERFLOW.mark();
warn!("Prometheus Buffer Size Exceeded: {}", BUFFER_FLUSH_THRESHOLD);
let _ = self.flush_inner(buffer);
} else {
if self.get_buffering().is_none() {
if let Err(e) = self.flush_inner(buffer) {
debug!("Could not send to Prometheus {}", e)
}
}
}
}
fn flush_inner(&self, mut buf: RefMut<String>) -> error::Result<()> {
if buf.is_empty() { return Ok(()) }
match minreq::get(self.push_url.as_ref()).with_body(buf.as_ref()).send() {
Ok(_res) => {
metrics::PROMETHEUS_SENT_BYTES.count(buf.len());
trace!("Sent {} bytes to Prometheus", buf.len());
buf.clear();
Ok(())
}
Err(e) => {
metrics::PROMETHEUS_SEND_ERR.mark();
debug!("Failed to send buffer to Prometheus: {}", e);
Err(e.into())
}
}
}
}
impl WithAttributes for PrometheusScope {
fn get_attributes(&self) -> &Attributes { &self.attributes }
fn mut_attributes(&mut self) -> &mut Attributes { &mut self.attributes }
}
impl Buffered for PrometheusScope {}
impl queue_out::QueuedOutput for Prometheus {}
impl cache_out::CachedOutput for Prometheus {}
const BUFFER_FLUSH_THRESHOLD: usize = 65_536;
#[derive(Debug, Clone)]
pub struct PrometheusMetric {
prefix: String,
scale: isize,
}
impl Drop for PrometheusScope {
fn drop(&mut self) {
if let Err(err) = self.flush() {
warn!("Could not flush Prometheus metrics upon Drop: {}", err)
}
}
}
#[cfg(feature = "bench")]
mod bench {
use core::attributes::*;
use core::input::*;
use super::*;
use test;
#[bench]
pub fn immediate_prometheus(b: &mut test::Bencher) {
let sd = Prometheus::push_to("localhost:2003").unwrap().input();
let timer = sd.new_metric("timer".into(), InputKind::Timer);
b.iter(|| test::black_box(timer.write(2000, labels![])));
}
#[bench]
pub fn buffering_prometheus(b: &mut test::Bencher) {
let sd = Prometheus::push_to("localhost:2003").unwrap()
.buffered(Buffering::BufferSize(65465)).input();
let timer = sd.new_metric("timer".into(), InputKind::Timer);
b.iter(|| test::black_box(timer.write(2000, labels![])));
}
}