Metrics

@platformatic/kafka supports integration with Prometheus via prom-client.

To ensure maximum compatibility, no prom-client version is shipped with the package but you are instead required to provide your own via metrics.client option when creating any client.

If you provide both the metrics.client and metrics.registry (an instance of Registry) options, then @platformatic/kafka will register and provide the following metrics:

Name	Type	Description
kafka_producers	Gauge	Number of active Kafka producers.
kafka_produced_messages	Counter	Number of produced Kafka messages.
kafka_consumers	Gauge	Number of active Kafka consumers.
kafka_consumers_streams	Gauge	Number of active Kafka consumers streams.
kafka_consumers_topics	Gauge	Number of topics being consumed.
kafka_consumers_lags	Histogram	Lag of active Kafka consumers
kafka_consumed_messages	Counter	Number of consumed Kafka messages.

Optionally, you can provide labels with the metrics.label option.

Example

import * as client from 'prom-client'
import { Producer, stringSerializer } from '@platformatic/kafka'

const registry = new client.Registry()

// Create a producer with string serialisers
const producer = new Producer({
  clientId: 'my-producer',
  bootstrapBrokers: ['localhost:9092'],
  serializers: stringSerializers,
  metrics: { client, registry }
})

// Send messages
await producer.send({
  messages: [
    {
      topic: 'events',
      key: 'user-123',
      value: JSON.stringify({ name: 'John', action: 'login' }),
      headers: { source: 'web-app' }
    }
  ]
})

// Close the producer when done
await producer.close()

console.log(JSON.stringify(await registry.getMetricsAsJSON(), null, 2))