For context, please read Experiments with Kafka's head-of-line blocking.
To setup the experiment:
$ docker-compose up --build --force-recreate --renew-anon-volumes --remove-orphans --no-attach=kafka
In a different terminal:
$ bundle exec ruby producer.rb
To inspect the consumer group, attach to the Kafka server container and run:
$ docker exec -it $(docker ps --filter=name=queue-kafka-1 --quiet) bas
$ kafka-consumer-groups.sh --describe --group main-group --bootstrap-server localhost:9092