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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"
clientID N Input/Output A user-provided string sent with every request to the Kafka brokers for logging, debugging, and auditing purposes. "my-dapr-app"
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"
consumeRetryEnabled N Input/Output Enable consume retry by setting to "true". Default to false in Kafka binding component. "true", "false"
publishTopic Y Output The topic to publish to. "mytopic"
authRequired N Deprecated Enable SASL authentication with the Kafka brokers. "true", "false"
authType Y Input/Output Configure or disable authentication. Supported values: none, password, mtls, or oidc "password", "none"
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
oidcTokenEndpoint N Input/Output Full URL to an OAuth2 identity provider access token endpoint. Required when authType is set to oidc “https://identity.example.com/v1/token"
oidcClientID N Input/Output The OAuth2 client ID that has been provisioned in the identity provider. Required when authType is set to oidc dapr-kafka
oidcClientSecret N Input/Output The OAuth2 client secret that has been provisioned in the identity provider: Required when authType is set to oidc "KeFg23!"
oidcScopes N Input/Output Comma-delimited list of OAuth2/OIDC scopes to request with the access token. Recommended when authType is set to oidc. Defaults to "openid" "openid,kafka-prod"

Binding support

This component supports both input and output binding interfaces.

This component supports output binding with the following operations:

  • create

Authentication

Kafka supports a variety of authentication schemes and Dapr supports several: SASL password, mTLS, OIDC/OAuth2. Learn more about Kafka’s authentication method for both the Kafka binding and Kafka pub/sub components.

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 24, 2022: [kafka] updates to bindings and pubsub component docs (#2552) (bb27ffd1)