Kafka binding spec

Kafka binding spec

Detailed documentation on the Kafka binding component

Component format

To setup Kafka binding create a component of type bindings.kafka. See this guide on how to create and apply a binding configuration. For details on using secretKeyRef, see the guide on how to reference secrets in components.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: kafka-binding
  namespace: default
spec:
  type: bindings.kafka
  version: v1
  metadata:
  - name: topics # Optional. Used for input bindings.
    value: "topic1,topic2"
  - name: brokers # Required.
    value: "localhost:9092,localhost:9093"
  - name: consumerGroup # Optional. Used for input bindings.
    value: "group1"
  - name: publishTopic # Optional. Used for output bindings.
    value: "topic3"
  - name: authRequired # Required.
    value: "true"
  - name: saslUsername # Required if authRequired is `true`.
    value: "user"
  - name: saslPassword # Required if authRequired is `true`.
    secretKeyRef:
      name: kafka-secrets
      key: saslPasswordSecret
  - name: initialOffset # Optional. Used for input bindings.
    value: "newest"
  - name: maxMessageBytes # Optional.
    value: 1024
  - name: version # Optional.
    value: 1.0.0

Spec metadata fields

Field	Required	Binding support	Details	Example
topics	N	Input	A comma-separated string of topics.	`“mytopic1,topic2”`
brokers	Y	Input/Output	A comma-separated string of Kafka brokers.	`“localhost:9092,dapr-kafka.myapp.svc.cluster.local:9093”`
consumerGroup	N	Input	A kafka consumer group to listen on. Each record published to a topic is delivered to one consumer within each consumer group subscribed to the topic.	`“group1”`
publishTopic	Y	Output	The topic to publish to.	`“mytopic”`
authRequired	Y	Input/Output	Enable SASL authentication with the Kafka brokers.	`“true”`, `“false”`
saslUsername	N	Input/Output	The SASL username used for authentication. Only required if `authRequired` is set to `“true”`.	`“adminuser”`
saslPassword	N	Input/Output	The SASL password used for authentication. Can be `secretKeyRef` to use a secret reference. Only required if `authRequired` is set to `“true”`.	`“”`, `“KeFg23!”`
initialOffset	N	Input	The initial offset to use if no offset was previously committed. Should be “newest” or “oldest”. Defaults to “newest”.	`“oldest”`
maxMessageBytes	N	Input/Output	The maximum size in bytes allowed for a single Kafka message. Defaults to 1024.	`2048`
version	N	Input/Output	Kafka cluster version. Defaults to 1.0.0	`1.0.0`

Binding support

This component supports both input and output binding interfaces.

This component supports output binding with the following operations:

create

Specifying a partition key

When invoking the Kafka binding, its possible to provide an optional partition key by using the metadata section in the request body.

The field name is partitionKey.

Example:

curl -X POST http://localhost:3500/v1.0/bindings/myKafka \
  -H "Content-Type: application/json" \
  -d '{
        "data": {
          "message": "Hi"
        },
        "metadata": {
          "partitionKey": "key1"
        },
        "operation": "create"
      }'

Response

An HTTP 204 (No Content) and empty body will be returned if successful.

Last modified June 23, 2022: Merge pull request #2550 from ItalyPaleAle/cosmosdb-harcoded-dapr-version (cf03237)