Crate prometheus_client

source ·
Expand description

Client library implementation of the Open Metrics specification. Allows developers to instrument applications and thus enables operators to monitor said applications with monitoring systems like Prometheus.

Examples

use prometheus_client::encoding::{EncodeLabelSet, EncodeLabelValue};
use prometheus_client::encoding::text::encode;
use prometheus_client::metrics::counter::{Atomic, Counter};
use prometheus_client::metrics::family::Family;
use prometheus_client::registry::Registry;
use std::io::Write;

// Create a metric registry.
//
// Note the angle brackets to make sure to use the default (dynamic
// dispatched boxed metric) for the generic type parameter.
let mut registry = <Registry>::default();

// Define a type representing a metric label set, i.e. a key value pair.
//
// You could as well use `(String, String)` to represent a label set,
// instead of the custom type below.
#[derive(Clone, Debug, Hash, PartialEq, Eq, EncodeLabelSet)]
struct Labels {
  // Use your own enum types to represent label values.
  method: Method,
  // Or just a plain string.
  path: String,
};

#[derive(Clone, Debug, Hash, PartialEq, Eq, EncodeLabelValue)]
enum Method {
  GET,
  PUT,
};

// Create a sample counter metric family utilizing the above custom label
// type, representing the number of HTTP requests received.
let http_requests = Family::<Labels, Counter>::default();

// Register the metric family with the registry.
registry.register(
  // With the metric name.
  "http_requests",
  // And the metric help text.
  "Number of HTTP requests received",
  http_requests.clone(),
);

// Somewhere in your business logic record a single HTTP GET request.
http_requests.get_or_create(
    &Labels { method: Method::GET, path: "/metrics".to_string() }
).inc();

// When a monitoring system like Prometheus scrapes the local node, encode
// all metrics in the registry in the text format, and send the encoded
// metrics back.
let mut buffer = String::new();
encode(&mut buffer, &registry).unwrap();

let expected = "# HELP http_requests Number of HTTP requests received.\n".to_owned() +
               "# TYPE http_requests counter\n" +
               "http_requests_total{method=\"GET\",path=\"/metrics\"} 1\n" +
               "# EOF\n";
assert_eq!(expected, buffer);

See examples directory for more.

Modules

Enums

  • MaybeOwned
    Represents either borrowed or owned data.