Monkey Metrics

Small clojure layer on top of Prometheus metrics

Usage

Include the lib

com.monkeyprojects/metrics {:mvn/version "0.1.0-SNAPSHOT"}

You can create a metrics registry, add gauges and counters. Then you can have Prometheus scrape it from and endpoint, or push it to an OTLP or Push gateway endpoint.

(require '[monkey.metrics.prometheus :as p])

;; Create new registry.  It will contain the JVM metrics by default.
(def reg (p/make-registry))

;; Set up a gauge
(def g (p/make-gauge "test_gauge" reg))
;; Give it a value
(p/gauge-set g 100)

;; Scrape the registry
(p/scrape reg)
;; => "test_gauge 100
;;     ..."

Metrics Options

When creating a gauge or a counter, you can specify additional options as a map:

• :labels: labels to be specified on the metric, as string/string map.
• :description
• :callback: see below.

Callbacks

Gauges and counters either can be explicitly set using the set- functions, or you can provide a callback. This callback is a zero-arity function that will be invoked on each scrape operation.

(def c (p/make-counter "test_counter" reg {:callback (constantly 100)}))

(p/scrape reg)
;; => "test_counter 100"

OTLP

Instead of scraping, you can also set up a client that periodically pushes to an OTLP endpoint.

(require '[monkey.metrics.otlp :as o])

(def c (o/make-client "http://some-otlp.endpoint.org"
                      reg
                      {:headers {"X-Auth-Token" "secret-token"}
		       :interval 10})) ; seconds

The client will push depending on the interval, which is 60 seconds by default. Don't forget to .close the client when you're done with it.

LICENSE

MIT License

Copyright (c) 2026 by Monkey Projects