CODEWITHSUNDEEP
mavenspring-bootinstrumentationgrafanaprometheus
kramsiv94
kramsiv94

Reputation: 711

How do you export metrics from a Spring Boot application into Prometheus?

I have a simple Maven Spring-Boot Application (Java) and am using Prometheus to collect metric information from it. I have all of the necessary Prometheus dependencies in my pom file, and I have included the @EnablePrometheusEndpoint annotation to my @SpringBootApplication class, but when I run my application and try to access the metrics on localhost:8080/prometheus (which I think is the default endpoint where Prometheus sends instrumentation metrics?), I get a 401 error. Did I instrument my application correctly such that metrics can be collected by Prometheus using the @EnablePrometheusEndpoint annotation? Where does Prometheus show my instrumented metrics (is it in localhost:8080/prometheus)? I've also tried looking for these metrics in localhost:8080/metrics, but no luck. Any help is greatly appreciated.

@SpringBootApplication
@RestController
@EnablePrometheusEndpoint
public class Example {

    //Just a logger that keeps track of relevant information:
    private static final Logger LOGGER = Logger.getLogger(Example.class.getName());

    //counter for counting how many times an endpoint has been hit
    static final Counter myCounter = Counter.build()    
                                              .name("CounterName") //note: by convention, counters should have "_total" suffix
                                              .help("Total requests recorded by a specific endpoint")
                                              .labelNames("status")
                                              .register();
    @RequestMapping("/hello")
    String hello() {

        myCounter.labels("customLabel1").inc(); //increment the number of requests by one
        LOGGER.log(Level.INFO, "Number of times /hello has been hit: " + myCounter.labels("customLabel1").get());

        return "Hello world! This is an example response!";
    }

    @RequestMapping("/homepage")
    String homePage() {

        myCounter.labels("customLabel2").inc(); //increment the number of requests by one
        LOGGER.log(Level.INFO, "Number of times /homepage has been hit: " + myCounter.labels("customLabel2").get());

        return "this is the home page!!";
    }


    public static void main(String[] args) throws Exception {
        SpringApplication.run(Example.class, args);
    }

}

Below is my pom.xml file: 

<?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>com.example</groupId>
    <artifactId>springboot</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.8.RELEASE</version>
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>


        <!-- Prometheus dependencies -->
        <!-- The client -->
        <dependency>
            <groupId>io.prometheus</groupId>
            <artifactId>simpleclient</artifactId>
            <version>0.1.0</version>
        </dependency>

        <dependency>
            <groupId>io.prometheus</groupId>
            <artifactId>simpleclient_spring_boot</artifactId>
            <version>0.1.0</version>
        </dependency>

        <dependency>
            <groupId>io.prometheus</groupId>
            <artifactId>simpleclient_servlet</artifactId>
            <version>0.1.0</version>
        </dependency>
        <!-- Hotspot JVM metrics -->
        <dependency>
            <groupId>io.prometheus</groupId>
            <artifactId>simpleclient_hotspot</artifactId>
            <version>0.1.0</version>
        </dependency>
        <!-- Exposition HTTPServer -->
        <dependency>
            <groupId>io.prometheus</groupId>
            <artifactId>simpleclient_httpserver</artifactId>
            <version>0.1.0</version>
        </dependency>
        <!-- Pushgateway exposition -->
        <dependency>
            <groupId>io.prometheus</groupId>
            <artifactId>simpleclient_pushgateway</artifactId>
            <version>0.1.0</version>
        </dependency>

        <!-- Spring Boot Actuator for exposing metrics -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
            <version>1.5.8.RELEASE</version>
        </dependency>


    </dependencies>


</project>

And below is my prometheus.yml file, set (I think) to scrape my spring-boot app on localhost:8080 in the last few lines:

# my global config
global:
  scrape_interval:     15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
  evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.
  # scrape_timeout is set to the global default (10s).

  # Attach these labels to any time series or alerts when communicating with
  # external systems (federation, remote storage, Alertmanager).
  external_labels:
      monitor: 'codelab-monitor'

# Load rules once and periodically evaluate them according to the global 'evaluation_interval'.
rule_files:
  # - "first.rules"
  # - "second.rules"

# A scrape configuration containing exactly one endpoint to scrape:
# Here it's Prometheus itself.
scrape_configs:
  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
  - job_name: 'prometheus'

    # metrics_path defaults to '/metrics'
    # scheme defaults to 'http'.
    scrape_interval: 5s

    static_configs:
      - targets: ['localhost:9090']

#The following lines are meant to monitor my  spring boot app
  - job_name: 'hello_world_spring_boot'
    scrape_interval: 5s

    static_configs:
      - targets: ['localhost:8080']

This is what I see when I look at my prometheus dashboard, running on localhost:9090

Prometheus dashboard status 401 message

Upvotes: 2

Views: 5880

Answers (3)

floating_hammer
floating_hammer

Reputation: 439

For publishing custom metrics into Prometheus, you need to use a Prometheus Pushgateway.

More documentation can be found on these two links

Upvotes: 0

mahesh chakravarthi
mahesh chakravarthi

Reputation: 271

Try adding endpoints.prometheus.sensitive: false in your application.properties or manifest. This will make your prometheus endpoint unprotected and it will be available for scrape.

Upvotes: 1

Tom
Tom

Reputation: 4093

Your Prometheus is configured to look for metrics at http://localhost:8080/metrics (default) whereas @EnablePrometheusEndpoint exposes the metrics at http://localhost:8080/prometheus.

So, you should set metrics_path to prometheus in your prometheus.yml.

The 401 happens, because by default the metrics endpoint of Spring Boot Actuator is protected.

Upvotes: 2

Related Questions