The OpenTelemetry Collector, when configured with a Prometheus receiver, provides an integration with Micrometer to scrape Prometheus metrics. The Collector uses the Prometheus Receiver to fetch metrics from the configured path in the JDK’s HTTPServer class. From there, the metrics are processed and exported to Lightstep Observability.

To complete the integration, you will:

  • Configure Micrometer to use the Prometheus exporter.
  • Configure the Collector to use the Micrometer endpoint as a scrape target for the Prometheus receiver.
  • Enable the integration by adding it to a pipeline.

Prerequisites

You’ve configured the Collector to export metric data to Lightstep Observability.

Configure Micrometer reporting

You need to configure your Spring Boot application to use the Prometheus exporter. Then you need to define the Prometheus endpoint in the JDK’s HTTPServer class.

  1. Using Gradle or Maven, add Prometheus support to your Spring Boot application.

    Start tabs

    Gradle

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     implementation 
     'io.micrometer:micrometer-registry-prometheus:latest.release'
    

    Maven

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     <dependency>
       <groupId>io.micrometer</groupId>
       <artifactId>micrometer-registry-prometheus</artifactId>
       <version>${micrometer.version}</version>
     </dependency>
    

    End code tabs

  2. Configure the Spring Boot Actuator to expose the Prometheus endpoints.
    In the application.properties section, add the following:
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    management.endpoints.web.exposure.include=*
    management.endpoints.web.exposure.include=prometheus,health,info,metric
    management.health.probes.enabled=true
    management.endpoint.health.show-details=always
    
  3. In the JDK’s com.sun.net.httpserver.HTTPServer class, expose the scrape endpoint.
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public static PrometheusMeterRegistry prometheus() {
  PrometheusMeterRegistry prometheusRegistry = new PrometheusMeterRegistry(new PrometheusConfig() {

    @Override
    public Duration step() {
      return Duration.ofSeconds(10);
    }

    @Override
    @Nullable
    public String get(String k) {
      return null;
    }
  });
  try {
    HttpServer server = HttpServer.create(new InetSocketAddress(8080), 0);
    server.createContext("/prometheus", httpExchange -> {
      String response = prometheusRegistry.scrape();
      httpExchange.sendResponseHeaders(200, response.length());
      OutputStream os = httpExchange.getResponseBody();
      os.write(response.getBytes());
      os.close();
    });
    new Thread(server::start).run();
  } catch (IOException e) {
      throw new RuntimeException(e);
    }
  return prometheusRegistry;
}

For more details about using Micrometer with the Prometheus exporter, see the official Micrometer documentation.

Configure the Collector receiver

In the Collector configuration file, configure the Prometheus receiver to use the Micrometer Prometheus endpoint as a scrape target.

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receivers:
  prometheus:
      config:
        scrape_configs:
          - job_name: 'micrometer'
            scrape_inteval: 10s
            scrape_timeout: 20s
            metrics_path: '/actuator/prometheus'
            scheme: 'http'
            tls_config:
              Insecure_skip_verify: true
            static_configs:
              - targets: ['localhost:8080']

The OpenTelemetry repo’s README provides additional details about Prometheus receiver configuration.

More details about the Prometheus scrape configuration can be found here.

Enable the Collector receiver

Once the Micrometer receiver is configured, enable it by adding it to one or more pipelines as described in the Collector configuration documentation.

Validate metrics are reporting to Lightstep

You can validate that the metrics are reporting to Lightstep from the Metric details section of the Project Settings page.

  1. Open the Project settings page and scroll to the Metric details section.

  2. Search for Micrometer metric names. Search for metric

  3. If needed, click on the metric to edit the description and how the units are displayed in Lightstep.

Create a dashboard for the metrics

Use the Lightstep Terraform Provider to create a dashboard for the metrics.

Additional resources

For a more complete example that’s ready to run, see the Micrometer integration in Lightstep OpenTelemetry Examples.