Producers

Producers allow for custom metrics and events to be added to the Cinnamon Backends. The constructor of a Producer should accept a Backends parameter. The Backends interface exposes methods with which it is possible to dynamically add and remove metrics and events via the methods MetricFactory metricsFor(Identity identity) and EventFactory eventsFor(Identity identity). This means that it is possible to create and delete metrics and events in runtime and that these are added to all configured backends.

An alternative to using a Producer is to use a Registrant. Registrant is for when you specifically have existing Coda Hale Metrics MetricSets. If you’re producing or importing metrics yourself, i.e. not an existing MetricSet or MetricRegistry, then Producer is a better choice.

Implementing a Producer

To implement a Producer, complete the steps here below.

Import

Import the Backends and Producer interfaces:

Scala

copyimport com.lightbend.cinnamon.backend.Backends
import com.lightbend.cinnamon.producer.Producer

Java

copyimport com.lightbend.cinnamon.backend.Backends;
import com.lightbend.cinnamon.producer.Producer;

Extend and construct

Extend the Producer abstract class. The constructor should accept a Backends parameter, to be able to add metrics and events to Cinnamon:

Scala

copyclass SampleProducer(backends: Backends) extends Producer {

Java

copypublic class SampleProducerJava extends Producer {
  public SampleProducerJava(Backends backends) {
  }

Implement stop method

Implement the stop method to clean up any resources and destroy created metrics:

Scala

copyoverride def stop() = {
  someResource.cleanUp()
  someLongGauge.destroy()
  someDoubleGauge.destroy()
}

Java

copy@Override
public void stop() {
  someResource.cleanUp();
  someLongGauge.destroy();
  someDoubleGauge.destroy();
}

Enable via configuration

Enable the Producer by adding a configuration section to cinnamon.producers which contains a producer-class setting for the fully qualified class name:

Scala

copycinnamon {
  producers += sample-producer

  sample-producer {
    producer-class = "sample.producer.SampleProducer"
  }
}

Java

copycinnamon {
  producers += sample-producer

  sample-producer {
    producer-class = "sample.producer.SampleProducerJava"
  }
}

Full example

The example below is naive in that it does not provide a whole lot of information in the form of metrics. It does, however, showcase a couple of important parts; the first one being how to write a complete implementation of a Producer, and the second important part is the use of ProvidingGauges. The latter means that the value will be fetched when data is being reported, and this frequency is related to how the reporter(s) have been configured. It alleviates you from having to set up any internal scheduler to push data to the metrics backend(s), which, of course, also is a possible solution.

Scala

copypackage sample.producer

import com.lightbend.cinnamon.backend.Backends
import com.lightbend.cinnamon.producer.Producer
import com.lightbend.cinnamon.meta.{ Descriptor, Identity }
import com.lightbend.cinnamon.metric.{ DoubleValueProvider, LongValueProvider }

class SampleProducer(backends: Backends) extends Producer {

  val someResource = new SomeResource

  val resourceIdentity = Identity
    .createFor("resources", "resource") // category and key
    .withName("some-resource")
    .withParent(backends.getCinnamonMeta().getApplicationIdentity())
    .build()

  val metricFactory = backends.metricsFor(resourceIdentity)

  val someLongGauge = metricFactory.createProvidingGaugeLong(
    new Descriptor.Builder().withKey("some-long-value").build(),
    new LongValueProvider {
      override def currentValue(): Long = someResource.getLongValue()
    }
  )

  val someDoubleGauge = metricFactory.createProvidingGaugeDouble(
    new Descriptor.Builder().withKey("some-double-value").build(),
    new DoubleValueProvider {
      override def currentValue(): Double = someResource.getDoubleValue()
    }
  )

  override def stop() = {
    someResource.cleanUp()
    someLongGauge.destroy()
    someDoubleGauge.destroy()
  }

}

Java

copypackage sample.producer;

import com.lightbend.cinnamon.backend.Backends;
import com.lightbend.cinnamon.producer.Producer;
import com.lightbend.cinnamon.meta.Descriptor;
import com.lightbend.cinnamon.meta.Identity;
import com.lightbend.cinnamon.metric.MetricFactory;
import com.lightbend.cinnamon.metric.ProvidingGaugeDouble;
import com.lightbend.cinnamon.metric.ProvidingGaugeLong;

public class SampleProducerJava extends Producer {

  private final SomeResource someResource;

  private final ProvidingGaugeLong someLongGauge;
  private final ProvidingGaugeDouble someDoubleGauge;

  public SampleProducerJava(Backends backends) {

    this.someResource = new SomeResource();

    Identity resourceIdentity =
        Identity.createFor("resources", "resource") // category and key
            .withName("some-resource")
            .withParent(backends.getCinnamonMeta().getApplicationIdentity())
            .build();

    MetricFactory metricFactory = backends.metricsFor(resourceIdentity);

    this.someLongGauge =
        metricFactory.createProvidingGaugeLong(
            new Descriptor.Builder().withKey("some-long-value").build(),
            () -> someResource.getLongValue());

    this.someDoubleGauge =
        metricFactory.createProvidingGaugeDouble(
            new Descriptor.Builder().withKey("some-double-value").build(),
            () -> someResource.getDoubleValue());
  }


  @Override
  public void stop() {
    someResource.cleanUp();
    someLongGauge.destroy();
    someDoubleGauge.destroy();
  }


}