Chris Pettitt created BEAM-2704: ----------------------------------- Summary: KafkaIO: NPE without key serializer set Key: BEAM-2704 URL: https://issues.apache.org/jira/browse/BEAM-2704 Project: Beam Issue Type: Bug Components: sdk-java-extensions Reporter: Chris Pettitt Assignee: Davor Bonaci
The KafkaIO javadoc implies that you do not need to set a Serializer if you only want to emit values: {code} * <p>Often you might want to write just values without any keys to Kafka. Use {@code values()} to * write records with default empty(null) key: * * <pre>{@code * PCollection<String> strings = ...; * strings.apply(KafkaIO.<Void, String>write() * .withBootstrapServers("broker_1:9092,broker_2:9092") * .withTopic("results") * .withValueSerializer(new StringSerializer()) // just need serializer for value * .values() * ); * }</pre> {code} However, if you don't set the key serializer then Kafka blows up when trying to instantiate the key serializer (in Kafka 0.10.1, at least). It would be more convenient if KafkaIO worked as documented and assigned a null serializer if values() is used. Relevant stack trace: {code} Caused by: java.lang.NullPointerException at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:230) at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:163) at org.apache.beam.sdk.io.kafka.KafkaIO$KafkaWriter.setup(KafkaIO.java:1582) at org.apache.beam.sdk.io.kafka.KafkaIO$KafkaWriter$DoFnInvoker.invokeSetup(Unknown Source) {code} -- This message was sent by Atlassian JIRA (v6.4.14#64029)