micrometer-clj

Clojure wrapper for java micrometer library. Provides several functions and macros wrapping micrometer meters.

Creating meter registry

Meter registries are created using single metrics function supplied with configuration. Creating and using simple in-memory meter registry:

(ns example 
  (:require [io.resonant.micrometer :as m]))

(m/configure {:type :simple, :tags {:foo "BAR"}})

(defn -main [& args]
  (m/timed ["some.metric" {:baz "BAG"}]
    (Thread/sleep 3000)))

When using global meter registry is not desired, it is possible to declare own registry using metrics function and create custom meters using get-* functions:

(let [registry (m/meter-registry {:type :prometheus})
      timer    (m/get-timer registry "frobnication.time" {:location "WAW"} 
                {:description "Frobnication request handling"})
      errors   (m/get-counter registry "frobnication.errors" {:location "WAW"} 
                {:description "Number of frobnication errors", :base-unit "err"})]
  (m/timed [timer] 
    (try
      (frobnicate)
    (catch Exception _
      (m/add-counter errors 1)))))

Listing and querying meters

Function list-meters will return names of all meters in a registry:

(m/list-meters)  ; there is also variant that accepts "registry" parameter
{:names ["process.uptime" "jvm.gc.max.data.size" "jvm.threads.peak" ... "jvm.threads.daemon"]}

In order to query specific meter use query-meters function:

(m/inspect-meter "jvm.memory.used") ; there is also variant that accepts "registry" parameter
{:name "jvm.memory.used",
 :measurements ({:statistic "VALUE", :value 2.90950008E8}),
 :availableTags {"area" ["heap" "nonheap"],
                 "id" ["Compressed Class Space" "G1 Eden Space" "CodeHeap 'non-nmethods'" "CodeHeap 'profiled nmethods'"
                       "CodeHeap 'non-profiled nmethods'" "Metaspace" "G1 Survivor Space" "G1 Old Gen"]},
 :description "The amount of used memory",
 :baseUnit "bytes"}

It is possible to query meters for specific tag:

(m/query-meter registry "jvm.memory.used" {"area" "heap"})
{:name "jvm.memory.used",
 :measurements ({:statistic "VALUE", :value 2.18463168E8}),
 :availableTags {"area" ["heap"], "id" ["G1 Eden Space" "G1 Survivor Space" "G1 Old Gen"]},
 :description "The amount of used memory",
 :baseUnit "bytes"}

More information

For more detailed documentation, see following documents:

• REGISTRY - creating and configuring meter registry, information about all supported implementations;

• METERS - creating and using meters of various types;

• DRIVERS - various meter registry backends list and configuration options;

License

Copyright © Rafal Lewczuk 2020 rafal.lewczuk@jitlogic.com

This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at http://www.eclipse.org/legal/epl-2.0.

This Source Code may also be made available under the following Secondary Licenses when the conditions for such availability set forth in the Eclipse Public License, v. 2.0 are satisfied: GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, with the GNU Classpath Exception which is available at https://www.gnu.org/software/classpath/license.html.