My aim - create spring boot application, collect metrics using DropWizard and expose endpoint for Prometheus to consume application metrics:
My code:
@SpringBootApplication
@EnableMetrics(proxyTargetClass = true)
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
package com.example.demo;
import com.codahale.metrics.Counter;
import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.annotation.Timed;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.PostConstruct;
import java.util.concurrent.atomic.AtomicLong;
@RestController
public class HelloController {
private AtomicLong atomicLong = new AtomicLong();
private Counter counter;
@Autowired
private MetricRegistry metricRegistry;
@PostConstruct
public void init() {
counter = metricRegistry.counter("counter");
}
@GetMapping("/hello")
@Timed(name = "my-index")
public String index() {
counter.inc();
return "Greetings from Spring Boot!. count=" + atomicLong.incrementAndGet();
}
}
package com.example.demo;
import com.codahale.metrics.ConsoleReporter;
import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.jvm.FileDescriptorRatioGauge;
import com.codahale.metrics.jvm.GarbageCollectorMetricSet;
import com.codahale.metrics.jvm.MemoryUsageGaugeSet;
import com.codahale.metrics.jvm.ThreadStatesGaugeSet;
import com.codahale.metrics.servlets.AdminServlet;
import com.codahale.metrics.servlets.CpuProfileServlet;
import com.codahale.metrics.servlets.MetricsServlet;
import com.ryantenney.metrics.spring.config.annotation.EnableMetrics;
import com.ryantenney.metrics.spring.config.annotation.MetricsConfigurerAdapter;
import io.prometheus.client.dropwizard.DropwizardExports;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.concurrent.TimeUnit;
@Configuration
public class Config /*extends MetricsConfigurerAdapter*/ {
//@Override
//public void configureReporters(MetricRegistry metricRegistry) {
// // registerReporter allows the MetricsConfigurerAdapter to
// // shut down the reporter when the Spring context is closed
// // registerReporter(ConsoleReporter
// // .forRegistry(metricRegistry)
// // .build())
// // .start(1, TimeUnit.MINUTES);
// new DropwizardExports(metricRegistry).register();
//}
@Bean
public DropwizardExports dropwizardExports(MetricRegistry metricRegistry){
DropwizardExports dropwizardExports = new DropwizardExports(metricRegistry);
dropwizardExports.register();
return dropwizardExports;
}
@Bean
public MetricRegistry metricRegistry() {
MetricRegistry metricRegistry = new MetricRegistry();
metricRegistry.registerAll(new GarbageCollectorMetricSet());
metricRegistry.registerAll(new MemoryUsageGaugeSet());
metricRegistry.registerAll(new ThreadStatesGaugeSet());
return metricRegistry;
}
@Bean
public ConsoleReporter consoleReporter(MetricRegistry metricRegistry) {
ConsoleReporter reporter = ConsoleReporter.forRegistry(metricRegistry).build();
reporter.start(5, TimeUnit.SECONDS);
reporter.report();
return reporter;
}
@Bean
public ServletRegistrationBean<MetricsServlet> registerMetricsServlet(MetricRegistry metricRegistry) {
return new ServletRegistrationBean<>(new MetricsServlet(metricRegistry), "/metrics/*");
}
@Bean
public ServletRegistrationBean<CpuProfileServlet> registerCpuServlet() {
return new ServletRegistrationBean<>(new CpuProfileServlet(), "/cpu/*");
}
}
build.gradle:
plugins {
id 'org.springframework.boot' version '2.7.1'
id 'io.spring.dependency-management' version '1.0.11.RELEASE'
id 'java'
}
group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '17'
repositories {
mavenCentral()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation "org.springframework.boot:spring-boot-starter-actuator"
// Minimum required for metrics.
implementation ('com.ryantenney.metrics:metrics-spring:3.1.3') {
exclude group: 'com.codahale.metrics'
exclude group: 'org.springframework'
}
implementation 'io.dropwizard.metrics:metrics-core:4.2.9'
implementation 'io.dropwizard.metrics:metrics-annotation:4.2.9'
implementation 'io.dropwizard.metrics:metrics-servlets:4.2.9'
implementation 'io.prometheus:simpleclient_dropwizard:0.15.0'
implementation 'io.prometheus:simpleclient_servlet:0.15.0'
implementation 'io.dropwizard:dropwizard-core:2.1.0'
implementation 'com.ryantenney.metrics:metrics-spring:3.1.3'
implementation 'io.prometheus:simpleclient_common:0.16.0'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
tasks.named('test') {
useJUnitPlatform()
}
I access localhost:8080/metrics and receive following response:
{
"version": "4.0.0",
"gauges": {
"G1-Old-Generation.count": {
"value": 0
},
"G1-Old-Generation.time": {
"value": 0
},
"G1-Young-Generation.count": {
"value": 7
},
"G1-Young-Generation.time": {
"value": 31
},
"blocked.count": {
"value": 0
},
"count": {
"value": 26
},
"daemon.count": {
"value": 22
},
"deadlock.count": {
"value": 0
},
"deadlocks": {
"value": []
},
"heap.committed": {
"value": 301989888
},
"heap.init": {
"value": 532676608
},
"heap.max": {
"value": 8518631424
},
"heap.usage": {
"value": 0.008041180864688155
},
"heap.used": {
"value": 68499856
},
"new.count": {
"value": 0
},
"non-heap.committed": {
"value": 51707904
},
"non-heap.init": {
"value": 2555904
},
"non-heap.max": {
"value": -1
},
"non-heap.usage": {
"value": -5.0738536E7
},
"non-heap.used": {
"value": 50738536
},
"peak.count": {
"value": 32
},
"pools.CodeCache.committed": {
"value": 10551296
},
"pools.CodeCache.init": {
"value": 2555904
},
"pools.CodeCache.max": {
"value": 50331648
},
"pools.CodeCache.usage": {
"value": 0.2039642333984375
},
"pools.CodeCache.used": {
"value": 10265856
},
"pools.Compressed-Class-Space.committed": {
"value": 5177344
},
"pools.Compressed-Class-Space.init": {
"value": 0
},
"pools.Compressed-Class-Space.max": {
"value": 1073741824
},
"pools.Compressed-Class-Space.usage": {
"value": 0.004625104367733002
},
"pools.Compressed-Class-Space.used": {
"value": 4966168
},
"pools.G1-Eden-Space.committed": {
"value": 188743680
},
"pools.G1-Eden-Space.init": {
"value": 29360128
},
"pools.G1-Eden-Space.max": {
"value": -1
},
"pools.G1-Eden-Space.usage": {
"value": 0.26666666666666666
},
"pools.G1-Eden-Space.used": {
"value": 50331648
},
"pools.G1-Eden-Space.used-after-gc": {
"value": 0
},
"pools.G1-Old-Gen.committed": {
"value": 109051904
},
"pools.G1-Old-Gen.init": {
"value": 503316480
},
"pools.G1-Old-Gen.max": {
"value": 8518631424
},
"pools.G1-Old-Gen.usage": {
"value": 0.0017806278080379123
},
"pools.G1-Old-Gen.used": {
"value": 15168512
},
"pools.G1-Old-Gen.used-after-gc": {
"value": 15168512
},
"pools.G1-Survivor-Space.committed": {
"value": 4194304
},
"pools.G1-Survivor-Space.init": {
"value": 0
},
"pools.G1-Survivor-Space.max": {
"value": -1
},
"pools.G1-Survivor-Space.usage": {
"value": 0.7151832580566406
},
"pools.G1-Survivor-Space.used": {
"value": 2999696
},
"pools.G1-Survivor-Space.used-after-gc": {
"value": 2999696
},
"pools.Metaspace.committed": {
"value": 35979264
},
"pools.Metaspace.init": {
"value": 0
},
"pools.Metaspace.max": {
"value": -1
},
"pools.Metaspace.usage": {
"value": 0.9868604316086066
},
"pools.Metaspace.used": {
"value": 35506512
},
"runnable.count": {
"value": 10
},
"terminated.count": {
"value": 0
},
"timed_waiting.count": {
"value": 5
},
"total.committed": {
"value": 353697792
},
"total.init": {
"value": 535232512
},
"total.max": {
"value": 8518631423
},
"total.used": {
"value": 119238392
},
"total_started.count": {
"value": 47
},
"waiting.count": {
"value": 11
}
},
"counters": {
"counter": {
"count": 9
}
},
"histograms": {},
"meters": {},
"timers": {}
}
Obviously this output is not applicable for Prometheus (all dots should be replaced with "_" at least)
How can I make output in format ready for prometheus ?
Based on documentation I've understand that class io.prometheus.client.dropwizardDropwizardExports is responsible for generating metric in format ready for Prometheus but I can't understand how.
I don't see significant difference but it is working example:
public class JavaDropwizard {
// Create registry for Dropwizard metrics.
static final MetricRegistry metrics = new MetricRegistry();
// Create a Dropwizard counter.
static final Counter counter = metrics.counter("my.example.counter.total");
public static void main( String[] args ) throws Exception {
// Increment the counter.
counter.inc();
// Hook the Dropwizard registry into the Prometheus registry
// via the DropwizardExports collector.
CollectorRegistry.defaultRegistry.register(new DropwizardExports(metrics));
// Expose Prometheus metrics.
Server server = new Server(1234);
ServletContextHandler context = new ServletContextHandler();
context.setContextPath("/");
server.setHandler(context);
context.addServlet(new ServletHolder(new MetricsServlet()), "/metrics");
// Add metrics about CPU, JVM memory etc.
DefaultExports.initialize();
// Start the webserver.
server.start();
server.join();
}
}
pom.xml
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>io.robustperception.java_examples</groupId>
<artifactId>java_dropwizard</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
</properties>
<name>java_dropwizard</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>io.prometheus</groupId>
<artifactId>simpleclient</artifactId>
<version>0.15.0</version>
</dependency>
<dependency>
<groupId>io.prometheus</groupId>
<artifactId>simpleclient_hotspot</artifactId>
<version>0.15.0</version>
</dependency>
<dependency>
<groupId>io.prometheus</groupId>
<artifactId>simpleclient_servlet</artifactId>
<version>0.15.0</version>
</dependency>
<dependency>
<groupId>io.prometheus</groupId>
<artifactId>simpleclient_dropwizard</artifactId>
<version>0.15.0</version>
</dependency>
<dependency>
<groupId>io.dropwizard.metrics</groupId>
<artifactId>metrics-core</artifactId>
<version>4.2.9</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-servlet</artifactId>
<version>8.1.7.v20120910</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
</plugin>
<!-- Build a full jar with dependencies -->
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>io.robustperception.java_examples.JavaDropwizard</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>