FYI, I have already created the following issue:
- https://issues.apache.org/jira/browse/FLINK-27872 >From the issue description directly: Currently, KafkaBuilder <https://github.com/apache/flink/blob/master/flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/connector/kafka/source/KafkaSourceBuilder.java> has two setters: - setTopics <https://github.com/apache/flink/blob/586715f23ef49939ab74e4736c58d71c643a64ba/flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/connector/kafka/source/KafkaSourceBuilder.java#L157> - setTopicPattern <https://github.com/apache/flink/blob/586715f23ef49939ab74e4736c58d71c643a64ba/flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/connector/kafka/source/KafkaSourceBuilder.java#L168> which under the hood instantiate the corresponding (concrete) subscribers. This covers the most common needs, I agree, but it might fall short in some cases. Why not add a more generic setter: - setKafkaSubscriber (???) *Otherwise, how can users read from kafka in combination with custom subscribing logic? Without looking much into it, it seems that they basically cannot, at least without having to replicate some parts of the connector, which seems rather inconvenient.*
