2 releases
0.1.1 | Sep 1, 2021 |
---|---|
0.1.0 | Sep 1, 2021 |
#781 in Debugging
Used in hesione_macros
38KB
691 lines
Hesione
A Prometheus client
Overview
There are a handful of other Prometheus clients for Rust already, but I decided to make another one. Rust has a lot of language features, and I felt like none of the existing implementations were truly using those to their advantage. With Hesione, traits are leveraged to make metric storage types pluggable, and a derive macro exists to make defining metrics and generating their collective outputs easy, among other things.
Also, my GitLab instance has GitHub and GitLab.com account sign-in enabled, so if you'd like to open issues or contribute code, please feel free to do so!
Features
- Rust things:
- Codegen that simplifies metric definitions
- Easy to instrument your code with
- Well-tested
- Process metrics
- Prometheus things:
- Counters
- Gauges
- Histograms
- Summaries
Examples
use std::sync::{
Arc,
atomic::{Ordering, AtomicUsize},
};
use once_cell::sync::Lazy;
use hesione::{Hesione, Counter, labels};
/// The collection of metrics used by your program
#[derive(Hesione)]
struct Metrics {
/// The amount of HTTP requests
///
/// Extra documentation that won't show up in Prometheus' help text can go
/// here. For example, I'll take this moment to mention that `AtomicUsize`
/// is just an arbitrary choice here. If you'd like to use another type to
/// store the value in, this is possible (with the stipulation that the type
/// you want implements the `hesione::Value` trait).
http_reqs: Counter<AtomicUsize>,
}
/// A globally usable instance of the above structure
///
/// This isn't strictly necessary, although it will likely make instrumentation
/// much easier.
static METRICS: Lazy<Metrics> = Lazy::new(Metrics::default);
// Instrument your code by importing METRICS and modifying its fields:
METRICS.http_reqs.inc(Ordering::SeqCst, None);
// You can also add labels when accessing a metric:
let labels = labels! {
"status_code": 404.to_string(),
}.unwrap();
METRICS.http_reqs.inc(Ordering::SeqCst, Some(labels));
// Call this method in your `/metrics` HTTP endpoint to generate the output:
let actual = METRICS.to_prometheus_lines(Ordering::SeqCst, None);
// This is what the output will look like for this example:
let expected = concat!(
// The help text comes from the first line of the doc comments
"# HELP http_reqs The amount of HTTP requests\n",
// Type hints are dictated by the struct's field type
"# TYPE http_reqs counter\n",
// Metric names are generated by the struct's field name
"http_reqs 1\n",
"http_reqs{status_code=\"404\"} 1\n",
"\n",
);
assert_eq!(expected, actual);
Contributing code
Be sure to run the .hooks/install.sh
script after the first clone. The
post-merge hook will re-run this script to apply changes to the hooks, if there
are any. The pre-commit hook runs the formatter, linter (on deny warnings mode),
and the test suite. If you don't want to run hard-mode linter or the tests for
some reason (maybe you already did and just don't want to do it again
automatically, or are committing code-unrelated things), you can set the
SKIP_TESTS_PLEASE
environment variable to anything.
License
This project is licensed under either of
-
Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
-
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Dependencies
~4–6MB
~111K SLoC