Deployment & Fault Tolerance

Expose Vert.x Metrics for Prometheus, visualize in Grafana

This document will show you how to expose Vert.x Metrics for Prometheus and visualize them in Grafana.

What you will build

You will build a web server that:

generates greetings upon request on the EventBus
replies to GET requests on the /greeting path,
exposes metrics for Prometheus on the /metrics path.

Then you will configure Prometheus to scrape the metrics and Grafana to visualize them.

The application fits in just a single MainVerticle class

What you need

A text editor or IDE
Java 11 or higher
Maven or Gradle
Prometheus (or Docker)
Grafana (or Docker)

Create a project

The code of this project contains Maven and Gradle build files that are functionally equivalent.

Using Maven

Here is the content of the pom.xml file you should be using:

Maven pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

  <modelVersion>4.0.0</modelVersion>

  <groupId>io.vertx.howtos</groupId>
  <artifactId>metrics-prometheus-grafana-howto</artifactId>
  <version>1.0-SNAPSHOT</version>

  <properties>
    <vertx.version>4.4.0</vertx.version>
  </properties>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>io.vertx</groupId>
        <artifactId>vertx-stack-depchain</artifactId>
        <version>${vertx.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <dependencies>
    <dependency>
      <groupId>io.vertx</groupId>
      <artifactId>vertx-web</artifactId>
    </dependency>
    <dependency>
      <groupId>io.vertx</groupId>
      <artifactId>vertx-micrometer-metrics</artifactId>
    </dependency>
    <dependency>
      <groupId>io.micrometer</groupId>
      <artifactId>micrometer-registry-prometheus</artifactId>
      <version>1.10.5</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.11.0</version>
        <configuration>
          <release>11</release>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.5.0</version>
        <configuration>
          <mainClass>io.vertx.howtos.metrics.MainVerticle</mainClass>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

Using Gradle

Assuming you use Gradle with the Kotlin DSL, here is what your build.gradle.kts file should look like:

Gradle build.gradle.kts

plugins {
  java
  application
}

repositories {
  mavenCentral()
}

java {
  toolchain {
    languageVersion.set(JavaLanguageVersion.of(11))
  }
}

dependencies {
  implementation(platform("io.vertx:vertx-stack-depchain:4.4.0"))
  implementation("io.vertx:vertx-web")
  implementation("io.vertx:vertx-micrometer-metrics")
  implementation("io.micrometer:micrometer-registry-prometheus:1.10.5")
}

application {
  mainClassName = "io.vertx.howtos.metrics.MainVerticle"
}

tasks.wrapper {
  gradleVersion = "7.6"
}