This distribution contains Java source code to provide Kafka Java client compatibility to Oracle Transactional Event Queues. Some Kafka Java producer and consumer applications can migrate seamlessly to Oracle Transactional Event Queues for scalable event streaming directly built into the Oracle Database.

You need to have Gradle 7.3 or above and Java installed.

This distribution contains version 23.4.0.0 of the Kafka Java Client for Oracle Transactional Event Queues project. It will be referred as OKafka-23.4.0.0 henceforth. This is tested with JDK 11.0.22 but we recommend using the latest version.

The Kafka Java Client works with Oracle Database 23ai Free version as well as Oracle Database 23ai available on Oracle Autonomous Cloud platform.

To test this distribution in free Oracle Cloud environment create Oracle Cloud account then create Oracle Autonomous Transaction Processing Database instance in cloud.

A database user should be created and should be granted the privileges mentioned in Database user configuration section. Then create a Transactional Event Queue to produce and consume messages.

To run OKafka application against Oracle Database, a database user must be created and must be granted below privileges.

create user <user> identified by <password>

GRANT AQ_USER_ROLE to user;
GRANT CONNECT, RESOURCE, unlimited tablespace to user;
GRANT EXECUTE on DBMS_AQ to user;
GRANT EXECUTE on DBMS_AQADM to user;
GRANT EXECUTE on DBMS_AQIN to user;
GRANT EXECUTE on DBMS_TEQK to user;
GRANT SELECT on GV_$SESSION to user;
GRANT SELECT on V_$SESSION to user;
GRANT SELECT on GV_$INSTANCE to user;
GRANT SELECT on GV_$LISTENER_NETWORK to user;
GRANT SELECT on GV_$PDBS to user;
GRANT SELECT on USER_QUEUE_PARTITION_ASSIGNMENT_TABLE to user;
GRANT SELECT on SYS.DBA_RSRC_PLAN_DIRECTIVES to user;
EXEC DBMS_AQADM.GRANT_PRIV_FOR_RM_PLAN('user');

Note: It is preferred in general to assign or grant a specific quota on a tablespace to a database user instead of granting unlimited quota in default tablespace. One can create a table space and use the following command to grant quota on a specific tablespace to a database user.

ALTER USER user QUOTA  UNLIMITED /* or size-clause */ on tablespace_name;

Once user is created and above privileges are granted, connect to Oracle Database as this user and create a Transactional Event Queue using below PL/SQL script. One can also use KafkaAdmin interface as shown in CreateTopic.java in examples directory to create a Transactional Event Queue.

-- Create an OKafka topic named 'TXEQ' with 5 partition and retention time of 7 days. 
begin
    dbms_aqadm.create_database_kafka_topic( topicname=> 'TXEQ', partition_num=>5, retentiontime => 7*24*3600);
end;

OKafka uses JDBC(thin driver) connection to connect to Oracle Database instance using any one of two security protocols.

1. PLAINTEXT
2. SSL

1.PLAINTEXT: In this protocol a JDBC connection is setup by providing username and password in plain text in ojdbc.prperties file. To use PLAINTEXT protocol user must provide following properties through application.

	security.protocol = "PLAINTEXT"
	bootstrap.servers  = "host:port"
	oracle.service.name = "name of the service running on the instance"        
	oracle.net.tns_admin = "location of ojdbc.properties file"  

ojdbc.properties file must have below properties

    user(in lowercase)=DatabaseUserName
    password(in lowercase)=Password

2.SSL: This protocol requires that, while connecting to Oracle Database, the JDBC driver authenticates database user using Oracle Wallet or Java KeyStore(JKS) files. This protocol is typically used to o connect to Oracle database 23ai instance in Oracle Autonomous cloud. To use this protocol Okafka application must specify following properties.

    security.protocol = "SSL"
    oracle.net.tns_admin = "location containing Oracle Wallet, tnsname.ora and ojdbc.properties file"
    tns.alias = "alias of connection string in tnsnames.ora"        

Directory location provided in oracle.net.tns_admin property should have

1. Oracle Wallet
2. tnsnames.ora file
3. ojdbc.properties file (optional) This depends on how the Oracle Wallet is configured.

Learn more about JDBC Thin Connections with a Wallet (mTLS) to establish secured JDBC connections.

Note: tnsnames.ora file in wallet downloaded from Oracle Autonomous Database contains JDBC connection string which is used for establishing JDBC connection.

Simplest way to build the okafka.jar file is by using Gradle build tool. This distribution contains gradle build files which will work for Gradle 7.3 or higher.

./gradle jar

This generates okafka-23.4.0.0.jar in okafka_source_dir/clients/build/libs.

Project Dependency:

Mandatory jar files for this project to work.

• ojdbc11-<version>.jar
• aqapi-<version>.jar
• oraclepki-<version>.jar
• osdt_core-<version>.jar
• osdt_cert-<version>.jar
• javax.jms-api-<version>.jar
• jta-<version>.jar
• slf4j-api-<version>.jar
• kafka-clients-3.7.1.jar

All these jars are downloaded from Maven Repository during gradle build.

To build the okafka.jar file which includes all the dependent jar files in itself.

./gradle fullJar 

This generates okafka-full-23.4.0.0.jar in okafka_source_dir/clients/build/libs.

This command generates javadoc in okafka_source_dir/clients/build/docs/javadoc

gradle javadoc

Repository contains 2 common OKafka application examples in examples folder.

1. ProducerOKafka.java Produces 10 messages into TxEQ topic.

2. ConsumerOKafka.java Consumes 10 messages from TxEQ topic.

For detailed documentation of OKafka please refer to Kafka API for Oracle Transactional Event Queues documentation.

For list of APIs supported with Oracle 23.4.0.0 version of OKafka please refer to OKafka 23ai javadoc.

This project is not accepting external contributions at this time. For bugs or enhancement requests, please file a GitHub issue unless it’s security related. When filing a bug remember that the better written the bug is, the more likely it is to be fixed. If you think you’ve found a security vulnerability, do not raise a GitHub issue and follow the instructions in our security policy.

Please consult the security guide for our responsible security vulnerability disclosure process

Copyright (c) 2019, 2024 Oracle and/or its affiliates.

Released under the Universal Permissive License v1.0 as shown at https://oss.oracle.com/licenses/upl/.