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

Examples

```rust 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, }

/// A globally usable instance of the above structure /// /// This isn't strictly necessary, although it will likely make instrumentation /// much easier. static METRICS: Lazy = 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! { "statuscode": 404.tostring(), }.unwrap(); METRICS.http_reqs.inc(Ordering::SeqCst, Some(labels));

// Call this method in your /metrics HTTP endpoint to generate the output: let actual = METRICS.toprometheuslines(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

at your option.