Table 1. Outgoing Attributes of the 'smallrye-kafka' connector
Attribute (alias) Description Mandatory Default

acks

The number of acknowledgments the producer requires the leader to have received before considering a request complete. This controls the durability of records that are sent. Accepted values are: 0, 1, all

Type: string

false

1

bootstrap.servers

(kafka.bootstrap.servers)

A comma-separated list of host:port to use for establishing the initial connection to the Kafka cluster.

Type: string

false

localhost:9092

buffer.memory

The total bytes of memory the producer can use to buffer records waiting to be sent to the server.

Type: long

false

33554432

close-timeout

The amount of milliseconds waiting for a graceful shutdown of the Kafka producer

Type: int

false

10000

cloud-events

Enables (default) or disables the Cloud Event support. If enabled on an incoming channel, the connector analyzes the incoming records and try to create Cloud Event metadata. If enabled on an outgoing, the connector sends the outgoing messages as Cloud Event if the message includes Cloud Event Metadata.

Type: boolean

false

true

cloud-events-data-content-type

(cloud-events-default-data-content-type)

Configure the default datacontenttype attribute of the outgoing Cloud Event. Requires cloud-events to be set to true. This value is used if the message does not configure the datacontenttype attribute itself

Type: string

false

cloud-events-data-schema

(cloud-events-default-data-schema)

Configure the default dataschema attribute of the outgoing Cloud Event. Requires cloud-events to be set to true. This value is used if the message does not configure the dataschema attribute itself

Type: string

false

cloud-events-insert-timestamp

(cloud-events-default-timestamp)

Whether or not the connector should insert automatically the time attribute into the outgoing Cloud Event. Requires cloud-events to be set to true. This value is used if the message does not configure the time attribute itself

Type: boolean

false

true

cloud-events-mode

The Cloud Event mode (structured or binary (default)). Indicates how are written the cloud events in the outgoing record

Type: string

false

binary

cloud-events-source

(cloud-events-default-source)

Configure the default source attribute of the outgoing Cloud Event. Requires cloud-events to be set to true. This value is used if the message does not configure the source attribute itself

Type: string

false

cloud-events-subject

(cloud-events-default-subject)

Configure the default subject attribute of the outgoing Cloud Event. Requires cloud-events to be set to true. This value is used if the message does not configure the subject attribute itself

Type: string

false

cloud-events-type

(cloud-events-default-type)

Configure the default type attribute of the outgoing Cloud Event. Requires cloud-events to be set to true. This value is used if the message does not configure the type attribute itself

Type: string

false

health-enabled

Whether health reporting is enabled (default) or disabled

Type: boolean

false

true

health-readiness-enabled

Whether readiness health reporting is enabled (default) or disabled

Type: boolean

false

true

health-readiness-timeout

deprecated - During the readiness health check, the connector connects to the broker and retrieves the list of topics. This attribute specifies the maximum duration (in ms) for the retrieval. If exceeded, the channel is considered not-ready. Deprecated: Use 'health-topic-verification-timeout' instead.

Type: long

false

health-readiness-topic-verification

deprecated - Whether the readiness check should verify that topics exist on the broker. Default to false. Enabling it requires an admin connection. Deprecated: Use 'health-topic-verification-enabled' instead.

Type: boolean

false

health-topic-verification-enabled

Whether the startup and readiness check should verify that topics exist on the broker. Default to false. Enabling it requires an admin client connection.

Type: boolean

false

false

health-topic-verification-timeout

During the startup and readiness health check, the connector connects to the broker and retrieves the list of topics. This attribute specifies the maximum duration (in ms) for the retrieval. If exceeded, the channel is considered not-ready.

Type: long

false

2000

kafka-configuration

Identifier of a CDI bean that provides the default Kafka consumer/producer configuration for this channel. The channel configuration can still override any attribute. The bean must have a type of Map<String, Object> and must use the @io.smallrye.common.annotation.Identifier qualifier to set the identifier.

Type: string

false

key

A key to used when writing the record

Type: string

false

key-serialization-failure-handler

The name set in @Identifier of a bean that implements io.smallrye.reactive.messaging.kafka.SerializationFailureHandler. If set, serialization failure happening when serializing keys are delegated to this handler which may provide a fallback value.

Type: string

false

key.serializer

The serializer classname used to serialize the record’s key

Type: string

false

org.apache.kafka.common.serialization.StringSerializer

max-inflight-messages

The maximum number of messages to be written to Kafka concurrently. It limits the number of messages waiting to be written and acknowledged by the broker. You can set this attribute to 0 remove the limit

Type: long

false

1024

merge

Whether the connector should allow multiple upstreams

Type: boolean

false

false

partition

The target partition id. -1 to let the client determine the partition

Type: int

false

-1

propagate-record-key

Propagate incoming record key to the outgoing record

Type: boolean

false

false

retries

If set to a positive number, the connector will try to resend any record that was not delivered successfully (with a potentially transient error) until the number of retries is reached. If set to 0, retries are disabled. If not set, the connector tries to resend any record that failed to be delivered (because of a potentially transient error) during an amount of time configured by delivery.timeout.ms.

Type: long

false

2147483647

topic

The consumed / populated Kafka topic. If neither this property nor the topics properties are set, the channel name is used

Type: string

false

tracing-enabled

Whether tracing is enabled (default) or disabled

Type: boolean

false

true

value-serialization-failure-handler

The name set in @Identifier of a bean that implements io.smallrye.reactive.messaging.kafka.SerializationFailureHandler. If set, serialization failure happening when serializing values are delegated to this handler which may provide a fallback value.

Type: string

false

value.serializer

The serializer classname used to serialize the payload

Type: string

true

waitForWriteCompletion

Whether the client waits for Kafka to acknowledge the written record before acknowledging the message

Type: boolean

false

true