Preface

The following examples use the freely available mqtt-dasbhoard broker. You should not use it for production purposes.

Local Development

The simplest way to test an MQTT implementation is to use an freely available broker like mqtt-dashboard.com. You do not need any credentials to connect to the broker. The examples use the mqtt-dashboard.com broker. If you want to host a broker for development purposes, you can use one of the following docker stacks:

MQTTKAFKA

Save this file as docker-compose.yml and start it with docker-compose up

version: '3'

services:
  # MQTT broker
  mosquitto:
    image: eclipse-mosquitto:latest
    ports:
      - "1883:1883"      # MQTT port
      - "9001:9001"      # WebSockets (if you want to enable it, you'll need to adjust the config)
    volumes:
      - ./mosquitto.conf:/mosquitto/config/mosquitto.conf

# use tools like https://github.com/EdJoPaTo/mqttui or mqtt-explorer to connect to the broker

Use this mosquitto.conf

listener 1883
allow_anonymous true
persistence false
log_dest stdout

# Uncomment if you want to enable MQTT over WebSockets
# listener 9001
# protocol websockets

Use tools like mqttui and mqtt-explorer to connect to the broker. The broker is available at localhost:1883.

version: '2.1'

services:
  zoo1:
    image: confluentinc/cp-zookeeper:7.3.2
    ports:
      - "2181:2181"
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_SERVER_ID: 1
      ZOOKEEPER_SERVERS: zoo1:2888:3888

  kafka1:
    image: confluentinc/cp-kafka:7.3.2
    ports:
      - "9092:9092"
      - "29092:29092"
      - "9999:9999"
    environment:
      KAFKA_ADVERTISED_LISTENERS: INTERNAL://kafka1:19092,EXTERNAL://${DOCKER_HOST_IP:-127.0.0.1}:9092,DOCKER://host.docker.internal:29092
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: INTERNAL:PLAINTEXT,EXTERNAL:PLAINTEXT,DOCKER:PLAINTEXT
      KAFKA_INTER_BROKER_LISTENER_NAME: INTERNAL
      KAFKA_ZOOKEEPER_CONNECT: "zoo1:2181"
      KAFKA_BROKER_ID: 1
      KAFKA_LOG4J_LOGGERS: "kafka.controller=INFO,kafka.producer.async.DefaultEventHandler=INFO,state.change.logger=INFO"
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_MIN_ISR: 1
      KAFKA_JMX_PORT: 9999
      KAFKA_JMX_HOSTNAME: ${DOCKER_HOST_IP:-127.0.0.1}
      KAFKA_AUTHORIZER_CLASS_NAME: kafka.security.authorizer.AclAuthorizer
      KAFKA_ALLOW_EVERYONE_IF_NO_ACL_FOUND: "true"
    depends_on:
      - zoo1

  # UI for watching kafka locally and debugging it
  kafka-ui:
      image: provectuslabs/kafka-ui
      ports:
          - '8080:8080'
      environment:
          - DYNAMIC_CONFIG_ENABLED=true
      depends_on:
        - kafka1

You can then connect to the ui at http://localhost:8080 and create a new kafka cluster. The bootstrap server is available at kafka1:29092.