I needed to test sending messages into a topic where the cleanup policy is compact (keep the most recent data for each key) … which means I needed a quick way to send a message with a key to Kafka. Fortunately, the kafka-consume-producer script supports key parsing. You just need to include a few –property parameters when running the script.

./kafka-console-producer.sh --bootstrap-server kafka.example.com:9092 --topic ljrtesting --property "parse.key=true" --property "key.separator=:"

When you send messages, they are in the format Key<deliminator>Message — so “LJRKey:1” will send a message with the key of “LJRKey” and the message content of “1”.