# Metrics

K2K provides deep insights into its runtime performance and operational health using the OpenTelemetry (**OTEL**) framework. This standardized approach allows you to seamlessly integrate K2K's metrics into your existing observability platforms, enabling robust monitoring, alerting, and performance analysis.

## **Built-in Exporter Support**

The application includes out-of-the-box support for several metric exporters. You can configure one of the following to direct telemetry data to your chosen destination:

* **Prometheus:** Exposes a standard `/metrics` endpoint that can be scraped by a Prometheus server, ideal for time-series monitoring and alerting in production environments.
* **Kafka:** exposes the metrics to a Kafka topic. Lenses, serving as the control plane, collects data and delivers it to the user.
* **Console:** For development and debugging purposes only. This exporter prints all collected metrics directly to the standard output, providing a simple way to inspect telemetry data locally without requiring any external backend.
* **OTLP:** Allows exporting data to any OTLP compatible platform.

## **Enabling and Configuring Metrics**

To activate metrics collection, you must launch the application with the telemetry flag and provide the necessary OpenTelemetry configuration.

1. Enable Telemetry: Use the `-t` flag with the `k2k start` command to initialize the telemetry module.
2. Configure the Exporter: Specify which exporter to use and its settings. This is typically managed through standard OpenTelemetry environment variables or a dedicated configuration file, depending on your deployment.

## Publishing Prometheus Metrics

To configure K2K to expose metrics for a Prometheus server, you would set the appropriate environment variables and then run the start command with the telemetry flag.

<pre class="language-yaml"><code class="lang-yaml"><strong>services:
</strong>  k2k:
    image: "https://hub.docker.com/layers/lensting/k2k/0.0.11-alpha"
    volumes:
      - ".:/pipelines"
    environment:
      OTEL_SERVICE_NAME: "k2k"
      OTEL_METRICS_EXPORTER: prometheus
      OTEL_EXPORTER_PROMETHEUS_HOST: "0.0.0.0"
      OTEL_TRACES_EXPORTER: none
      OTEL_LOGS_EXPORTER: none
    command:
      - k2k
      - start
      - -f
      - /pipelines/k2k-pipeline.yml
      - -t
      - -g
      - enabled
    ports:
      - 9464:9464
</code></pre>

## **Publishing Kafka Metrics**

<pre class="language-yaml"><code class="lang-yaml"><strong>services:
</strong>  k2k:
    image: "https://hub.docker.com/layers/lensting/k2k/0.0.11-alpha"
    volumes:
      - ".:/pipelines"
    environment:
      OTEL_SERVICE_NAME: "k2k"
      OTEL_METRICS_EXPORTER: kafka
      OTEL_TRACES_EXPORTER: none
      OTEL_LOGS_EXPORTER: none
    command:
      - k2k
      - start
      - -f
      - /pipelines/k2k-pipeline.yml
      - -t
      - -g
      - enabled
    ports:
      - 9464:9464
</code></pre>

## **Publishing Console Metrics**

```yaml
services:
  k2k:
    image: "https://hub.docker.com/layers/lensting/k2k/0.0.11-alpha"
    volumes:
      - ".:/pipelines"
    environment:
      OTEL_SERVICE_NAME: "k2k"
      OTEL_METRICS_EXPORTER: console
      OTEL_TRACES_EXPORTER: none
      OTEL_LOGS_EXPORTER: none
    command:
      - k2k
      - start
      - -f
      - /pipelines/k2k-pipeline.yml
      - -t
      - -g
      - enabled
    ports:
      - 9464:9464
```

## **Publishing OTLP Metrics**

```yaml
services:
  k2k:
    image: "https://hub.docker.com/layers/lensting/k2k/0.0.11-alpha"
    volumes:
      - ".:/pipelines"
    environment:
      OTEL_SERVICE_NAME:"k2k"
      OTEL_METRICS_EXPORTER:otlp
      OTEL_TRACES_EXPORTER:none
      OTEL_LOGS_EXPORTER:none
      OTEL_METRIC_EXPORT_INTERVAL:15000
      OTEL_EXPORTER_OTLP_PROTOCOL:"http/protobuf"
      OTEL_EXPORTER_OTLP_METRICS_ENDPOINT:"http://localhost:9090/api/v1/otlp/v1/metrics"    
    command:
      - k2k
      - start
      - -f
      - /pipelines/k2k-pipeline.yml
      - -t
      - -g
      - enabled
    ports:
      - 9464:9464
```