https://coutoarmando.medium.com/kafka-with-ruby-c772dc8d1fb8

kafka.rb

require 'kafka'

# Set up Kafka client
kafka = Kafka.new(
  seed_brokers: ['localhost:9092'],
  client_id: 'my_kafka_client'
)

# Create a producer
producer = kafka.producer

# Create a consumer
consumer = kafka.consumer(group_id: 'my_consumer_group')

# Define the topic
topic = 'my_topic'

# Publish messages to Kafka
producer.produce('Hello, Kafka!', topic: topic)
producer.deliver_messages

# Subscribe to the topic and consume messages
consumer.subscribe(topic)

# Start consuming messages
consumer.each_message do |message|
  puts "Received message: #{message.value}"
end

# Close connections
producer.shutdown
consumer.stop