Prometheus metrics code instrumentation Java

prometheus-metrics-java.java

import io.prometheus.client.Counter;
import io.prometheus.client.Gauge;
import io.prometheus.client.Histogram;
import io.prometheus.client.Summary;
import io.prometheus.client.exporter.HTTPServer;

import java.io.IOException;
import java.util.Random;

public class Main {

   private static double rand(double min, double max) {
       return min + (Math.random() * (max - min));
   }

   public static void main(String[] args) {
       Counter counter = Counter.build().namespace("java").name("my_counter").help("This is my counter").register();
       Gauge gauge = Gauge.build().namespace("java").name("my_gauge").help("This is my gauge").register();
       Histogram histogram = Histogram.build().namespace("java").name("my_histogram").help("This is my histogram").register();
       Summary summary = Summary.build().namespace("java").name("my_summary").help("This is my summary").register();

       Thread bgThread = new Thread(() -> {
           while (true) {
               try {
                   counter.inc(rand(0, 5));
                   gauge.set(rand(-5, 10));
                   histogram.observe(rand(0, 5));
                   summary.observe(rand(0, 5));


                   Thread.sleep(1000);
               } catch (InterruptedException e) {
                   e.printStackTrace();
               }
           }
       });
       bgThread.start();

       try {

           HTTPServer server = new HTTPServer(8080);
       } catch (IOException e) {
           e.printStackTrace();
       }
   }
}