This manual is for an old version of Hazelcast Jet, use the latest stable version.

StreamKafkaP is used to consume items from one or more Kafka topics. It uses the Kafka consumer API and consumer groups to distribute partitions among processors where each partition is consumed by a single processor at any given time. The reader emits items of type Map.Entry<K,V> where the key and the value are deserialized using the key/value deserializers configured in Kafka properties.

Ideally, the total partition count in Kafka should be at least as large as the total parallelism in the Jet cluster (localParallelism*clusterSize) to make sure that each processor will get some partitions assigned to it.

Internally, a KafkaConsumer is created per Processor instance using the supplied properties. All processors must be in the same consumer group supplied by the property. It is required that the is explicitly set by the user to a non-empty value. The supplied properties will be passed on to each KafkaConsumer instance. These processors are only terminated in case of an error or if the underlying job is cancelled.

StreamKafkaP forces the property to be set to false, and commits the current offsets after they have been fully emitted.