Apache Kafka Subscriber | X4Documentation

The adapter enables you to subscribe messages on a specific topic, unsubscribe, or read the last message.

Properties

Operation

Defines the operation executed by the adapter.

Possible values:

Assign: Manually assigns a list of partitions to a consumer.
Subscribe: Subscribes to a topic to receive messages.
Unsubscribe: Disconnects client and topic and unsubscribes from a specific topic.
Last offset: Returns the offset of a specific client for its subscribed topic.

Parameters

`trustStorePath`	Defines where the trust store to be used is located.
`trustStorePassword`	Password for the trust store
`keyStorePath`	Defines where the key store to be used is located.
`keystorePassword`	Password for the key store
`privateKeyPassword`	Password of the private key in the keystore file
`username`	User name for SASL/PLAIN authentication at the Kafka server If you use this parameter, the configuration properties `sasl.mechanism = PLAIN` and `security.protocol = SASL_SSL` are set.
`password`	Password for SASL/PLAIN authentication at the Kafka server If you use this parameter, the configuration properties `sasl.mechanism = PLAIN` and `security.protocol = SASL_SSL` are set.
`clusterId`	ID of the cluster with which the topic is subscribed Possible values: Cluster ID The ID of the cluster can be found in the file `apachekafka-config.xml`. It is located in the `id` attribute of the `Cluster` element.
`ClientId`	ID of the client with which the topic is subscribed Possible values: Client ID The ID of the cliente can be found in the file `apachekafka-config.xml`. It is located in the `id` attribute of the `Client` element.
`topic`	Name of the topic to be subscribed to Possible values: String consisting of alphanumeric ASCII characters, `.` (dot), `_` (underscore) and `-` (hyphen) or comma-separated list of multiple strings to subscribe to multiple topics
`process`	Process that is executed after a message is received. Possible values: String consisting of alphanumeric ASCII characters, `.` (dot), `_` (underscore) and `-` (hyphen)
`consumerPosition`	Offset with which messages are received when a topic is subscribed to. Possible values: Integer greater than `0` This parameter only has an effect if a single topic is subscribed to. If several topics are subscribed to, this parameter has no effect.
`messageDataType`	Data type of the message(s) to be published. Possible values: `BYTES`: Base64 encoded value `BYTEARRAY`: Base64 encoded value `DOUBLE`: Floating-point number `FLOAT`: Floating-point number `INTEGER`: Integer `LONG`: Integer `SHORT`: Integer `STRING` (default): String `UUID`: Java UUID Messages with different data types can be published in a topic. To read the messages with the Apache Kafka Subscriber Adapter, the data type must be known and set correctly. For example, a message of the data type `STRING` cannot be read with the data type setting `LONG`. Therefore, all messages in a topic should be of the same data type.
`keyDataType`	Data type of the key Possible values: `NONE` (default): No data type If the subscriber has subscribed to a topic and the `keyDataType` has the value `NONE`, only messages without a key will be received. If the value is other than `NONE`, messages with all other data types are received. If the message has a key, the key is output as an attribute in the `Content` element. `BYTES`: Base64 encoded value `BYTEARRAY`: Base64 encoded value `DOUBLE`: Floating-point number `FLOAT`: Floating-point number `INTEGER`: Integer `LONG`: Integer `SHORT`: Integer `STRING` (default): String `UUID`: Java UUID

The values of the trustStorePath, trustStorePassword, keyStorePath, keyStorePassword and privateKeyPassword parameters can also be defined in the apachekafka-config.xml file (see Apache Kafka).

The information about the adapter configuration overwrites the information in the apachekafka-config.xml. However, all parameters must be set for this. If not all parameters are set via the adapter configuration, the files from the apachekafka-config.xml are used.

If adapter parameters are used to override the SSL configuration of a particular client, then these values are retained until they are overridden again or the server is restarted.

Status values

`1`	The adapter operation was executed successfully.
`-1`	An error occurred during the execution of the adapter.