Symptoms
The standard Kafka consumer (kafka-console-consumer.sh) is unable to receive messages and hangs without producing any output.
Causes
This situation occurs if the consumer is invoked without supplying the required security credentials. In this case, the consumer hangs and does not output any messages sent to the topic.
Resolving the problem
Create a properties file with the following content:
security.protocol=SASL_SSL
ssl.protocol=TLSv1.2
ssl.truststore.location=<certs.jks_file_location>
ssl.truststore.password=<truststore_password>
sasl.mechanism=PLAIN
sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required username="token" password="<api_key>";
Replace <certs.jks_file_location> with the location of a trust store file containing the server certificate (for example, certs.jks), <truststore_password> with the password for the trust store and <api_key> with an API key able to access the Event Streams deployment.
When running the kafka-console-producer.sh command include the --consumer.config <properties_file> option, replacing the <properties_file> with the name of the property file and the path to it. For example:
kafka-console-consumer.sh --bootstrap-server <brokerIP>:<bootstrapPort> --topic <topic> -consumer.config <properties_file>