Writing a Message to a Kafka Topic

You can use the Apache Kafka Producer adapter to write a message to a Kafka topic. Create an action node and assign stereotype KafkaProducerAdapter. This action node has got the following parameters:

producerRecord is a complex structure that defines the message and target.The topic you want to write the message to is the only mandatory parameter.

Attribute	Type	Mandatory	Description
topic	String		Specify the topic the message should be sent do.
partition	Integer		Specify the partition the message should be send to.
key	Blob		Specify a key the message should be filed to.
id	Integer		Will be generated. We recommend not to set one manually.
headers	Array of MessageHeader		Specify headers if you want to provide additional information on the  message content for e.g. routing or filtering use cases.
value	Blob		Specify the actual message content. Only payload of type Blob is supported.

The Kafka Producer returns some meta data about the processing of the message.

Attribute	Type	Mandatory	Description	Allowed Values / Examples
topic	String		Kafka topic the message has been sent to.
partition	Integer		Topic partition the message has been sent to.
offset	Integer		Offset of the message within the partition.
recordId	Integer		The message ID as provided with the call, or as generated if it has not been specified.
keySize	Integer		Actual size of the key in bytes.
valueSize	Integer		Actual size of the value in bytes.
timestamp	DateTime		A processing timestamp (UTC). See timestampType for what the timestamp refers to.
timestampType	TimestampType		Indicates what the timestamp refers to.	NotAvailable	Timestamp is unknown.
				CreateTime	Timestamp relates to message creation time as set by a Kafka broker.
				LogAppendTime	Timestamp relates to the time a message was appended to a Kafka log.
persistedStatus	PersistedStatus		Status of the message.	NotPersisted	Message was never transmitted to the broker, or failed with an error indicating it was not written to the log.
				Persisted	Message was written to the log and acknowledged by the broker.
				PossiblyPersisted	Message was transmitted to broker, but no acknowledgement was received.

Transaction Handling

The xUML Runtime handles Apache Kafka Producer calls like is specified in the Runtime transaction concept. All producer calls within a session are wrapped into a dedicated transaction with a random unique transaction ID. These transactions can be rolled back until they have been committed.
You cannot set a custom transaction ID (transactional.id), therefore there will be no fencing.