Weblogic JMS Source Connector for Confluent Platform

Caution

Preview connectors aren’t currently supported, nor are they recommended for production use.

The Kafka Connect Weblogic JMS Source Connector is used to read messages from an Oracle Weblogic JMS Server and write them into an Apache Kafka® topic.

Note

Confluent Platform also includes a general JMS Source Connector for Confluent Platform that uses a JNDI-based mechanism to connect to the JMS broker. The Weblogic connector also connects using JNDI, but includes special support for JMS 2.0 Shared Subscriptions.

Features

The Weblogic JMS Source Connector includes the following features:

At least once delivery

This connector guarantees that records are delivered at least once to the Kafka topic. If the connector restarts, there may be some duplicate records in the Kafka topic.

JMS message types

The connector currently supports TextMessage and BytesMessage. The connector does not currently support ObjectMessage or StreamMessage.

Retries and reconnection

The connector can be configured to retry on retriable errors using the max.retry.time configuration property. This property sets the maximum time in milliseconds (ms) the connector will attempt to retry. The property defaults to 3600000 ms (1 hour). The connector uses exponential backoff after each retry attempt. That is, each subsequent retry attempt interval increases exponentially with jitter. The Weblogic JMS connector will attempt a retry for the following exceptions during connection/receive attempts:

  • javax.jms.IllegalStateException
  • weblogic.jms.common.JMSExceptionIllegalStateException

The IllegalStateException is thrown when a receive is attempted but the server is down. The JMSException is thrown when a connection is attempted and the server is down. Note that these retries will only activate if the connector was already successfully provisioned, and then at some point later on connection/receive fails. That is, a failure to connect during provisioning will not result in retries.

Jms 2.0 Shared Subscription Support

This connector supports consuming from JMS 2.0 shared subscriptions. Note that as JMS 2.0 support only begins in Weblogic 12.2.1.3, this connector only officially supports Weblogic versions >= 12.2.1.3. Further, there is an implementation incompatibility in Oracle’s Weblogic 12.2.1.3 that limits connectors using shared subscriptions to have a maximum tasks.max connector configuration of 1. If you wish to leverage JMS shared subscriptions and have Weblogic 12.2.1.3, one option is to use multiple connectors each with tasks.max set to 1, with each connector subscribed to the same JMS topic.

When connecting to Weblogic versions > 12.2.1.3, the connector can use more than one task during a shared subscription and each task will be a JMS shared consumer of the Weblogic JMS topic.

Install the Weblogic Source Connector

You can install this connector by using the Confluent Hub client installation instructions or by manually downloading the ZIP file.

Prerequisites

  • Kafka 1.1+ or Confluent Platform 4.1+
  • Oracle Weblogic v12.2.1.3+

Note

You must install the connector on every machine where Connect will run.

  • An installation of the Confluent Hub Client.

    Note

    This is installed by default with Confluent Enterprise.

  • An installation of the latest (latest) connector version.

    To install the latest connector version, navigate to your Confluent Platform installation directory and run the following command:

    confluent-hub install confluentinc/kafka-connect-weblogic:latest
    

    You can install a specific version by replacing latest with a version number as shown in the following example:

    confluent-hub install confluentinc/kafka-connect-weblogic:11.0.0
    

Install the connector manually

Download and extract the ZIP file for your connector and then follow the manual connector installation instructions.

License

You can use this connector for a 30-day trial period without a license key.

After 30 days, this connector is available under a Confluent enterprise license. Confluent issues Confluent enterprise license keys to subscribers, along with providing enterprise-level support for Confluent Platform and your connectors. If you are a subscriber, please contact Confluent Support at support@confluent.io for more information.

See Confluent license properties for license properties and information about the license topic.

Configuration Properties

For a complete list of configuration properties for this connector, see Weblogic JMS Source Connector Configuration Properties.

Note

For an example of how to get Kafka Connect connected to Confluent Cloud, see Distributed Cluster.

Client Libraries

To use the Kafka Connect Weblogic JMS Source connector, you must download the Weblogic JMS client library JAR files. Complete the following steps to get these JAR files.

Note

The exact list of JAR files from the Weblogic client library may vary depending on the Java software version.

  1. Follow the instructions at the Weblogic Support page Fusion Middleware Programming Stand-alone Clients for Oracle WebLogic Server. The page contains an overview of the available clients and how to install them. The connector is designed to be compatible with the Weblogic JMS thin client(wlthint3client.jar) but may be compatible with others, depending on your Weblogic Server version and which JARs it provides.

  2. Copy all of the required JAR files to the correct folder in /share/:

    cp WL_HOME/server/lib/wlthint3client.jar /$CONFLUENT_HOME/share/confluent-hub-components/confluentinc-kafka-connect-weblogic/
    

    Important

    These JAR files need to be copied for each of your Confluent Platform installations where you want to run this connector.

  3. List the JAR files to verify that they were copied successfully.

    ls -l /$CONFLUENT_HOME/share/confluent-hub-components/confluentinc-kafka-connect-weblogic/
    
  4. Ensure you have the wlthint3client.jar file.

Connecting to Weblogic Source

Before you can use this connector, you must install the Weblogic client JARs into this connector’s installation directory.

This connector connects to Weblogic using JNDI to create an instance of the JMS ConnectionFactory for your messaging system. See the section “Setting Up JNDI Environment Properties for the InitialContext” under Oracle’s Weblogic JNDI documentation.

The following example shows a typical configuration of the connector for use with distributed mode:

{
 "name": "connector1",
 "config": {
   "connector.class": "io.confluent.connect.weblogic.WeblogicSourceConnector",
   "kafka.topic":"MyKafkaTopicName",
   "java.naming.factory.initial": "weblogic.jndi.WLInitialContextFactory",
   "jms.destination.name":"MyWeblogicTopic",
   "jms.destination.type":"topic",
   "java.naming.provider.url": "t3://<host>:7001/",
   "connection.factory.name": "com.oracle.webservices.api.jms.ConnectionFactory",
   "confluent.license": "",
   "java.naming.security.principal": "weblogic",
   "java.naming.security.credentials": "welcome1",
   "tasks.max" : "1",
   "jms.client.id": "id1",
   "jms.subscription.durable": true,
   "jms.subscription.shared": true,
   "jms.subscription.name": "sub1",
   "confluent.topic.bootstrap.servers":"localhost:9092"
   }
}

The connector supports other configuration options not included in the example above.

Topics

This connector consumes messages from the JMS broker using the configured message selectors and writes them to a single Kafka topic. If you want to write messages to multiple topics, use a simple message transform that routes the messages based upon your criteria.

Acknowledgement Mode

The connector internally uses CLIENT_ACKNOWLEDGE mode to receive and acknowledge messages from the JMS broker. In this mode, acknowledging any message will acknowledge every message received (see section 6.2.10 in the JMS Spec). To prevent messages from being prematurely acknowledged, the connector processes only one message at time. In other words, the connector will not attempt to receive new messages until the last message is committed to a Kafka topic. This might compromise the throughput of the Connector, but messages will be transferred to Kafka successfully.

Schemas

The Weblogic connector produces messages with keys and values that adhere to the schemas described in the following sections.

io.confluent.connect.jms.Key

This schema is used to store the incoming MessageID on the message interface. This will ensure that when that if the same message ID arrives it will end up in the same partition. In practice this should never occur. The schema defines the following fields:

Name Schema Required Default Value Documentation
messageID STRING yes   This field stores the value of Message.getJMSMessageID().

io.confluent.connect.jms.Value

This schema is used to store the value of the JMS message. The schema defines the following fields:

Name Schema Required Default Value Documentation
messageID STRING yes   This field stores the value of Message.getJMSMessageID().
messageType STRING yes   This field stores the type of message that was received. This corresponds to the sub-interfaces of Message. BytesMessage = bytes, MapMessage = map, ObjectMessage = object, StreamMessage = stream and TextMessage = text. The corresponding field will be populated with the values from the respective message sub-interface.
timestamp INT64 yes   Data from the getJMSTimestamp() method.
deliveryMode INT32 yes   This field stores the value of Message.getJMSDeliveryMode(). method.
correlationID STRING no   This field stores the value of Message.getJMSCorrelationID(). method.
replyTo Destination no   This schema is used to represent a JMS Destination, and is either queue or topic.
destination Destination no   This schema is used to represent a JMS Destination, and is either queue or topic.
redelivered BOOLEAN yes   This field stores the value of Message.getJMSRedelivered().
type STRING no   This field stores the value of Message.getJMSType().
expiration INT64 no   This field stores the value of Message.getJMSExpiration().
priority INT32 no   This field stores the value of Message.getJMSPriority().
properties Map of STRING, PropertyValue yes   This field stores the data from all of the properties for the Message indexed by their propertyName.
bytes BYTES no   This field stores the value from BytesMessage.html.readBytes(byte[]).
map Map of STRING, PropertyValue no   This field stores the data from all of the map entries returned from MapMessage.getMapNames() for the Message indexed by their key.
text STRING no   This field stores the value from TextMessage.html.getText().

io.confluent.connect.jms.Destination

This schema is used to represent a JMS Destination, and is either queue or topic. The schema defines the following fields:

Name Schema Required Default Value Documentation
destinationType STRING yes   The type of JMS Destination, and either queue or topic.
name STRING yes   The name of the destination. This will be the value of Queue.getQueueName() or Topic.getTopicName().

io.confluent.connect.jms.PropertyValue

This schema is used to store the data that is found in the properties of the message. To ensure that the proper type mappings are preserved field propertyType stores the value type for the field. The corresponding field in the schema will contain the data for the property. This ensures that the data is retrievable as the type returned by Message.getObjectProperty(). The schema defines the following fields:

Name Schema Required Default Value Documentation
propertyType STRING yes   The Java type of the property on the Message. One of boolean, byte, short, integer, long, float, double, or string.
boolean BOOLEAN no   The value stored as a boolean. Null unless propertyType is set to boolean.
byte INT8 no   The value stored as a byte. Null unless propertyType is set to byte.
short INT16 no   The value stored as a short. Null unless propertyType is set to short.
integer INT32 no   The value stored as a integer. Null unless propertyType is set to integer.
long INT64 no   The value stored as a long. Null unless propertyType is set to long.
float FLOAT32 no   The value stored as a float. Null unless propertyType is set to float.
double FLOAT64 no   The value stored as a double. Null unless propertyType is set to double.
string STRING no   The value stored as a string. Null unless propertyType is set to string.