docker-compose.yml

---
version: '3.8'
services:
  ngrok:
    image: ngrok/ngrok:latest
    container_name: ngrok
    # # for an ngrok account at https://dashboard.ngrok.com/#
    # Get your auth-token from https://dashboard.ngrok.com/get-started/your-authtoken
    # and either put it directly in the file here, or write it to a .env file in 
    # the same folder as this Docker Compose file in the form
    # NGROK_AUTH_TOKEN=your_token_value
    command: tcp broker:9092 --log stdout --authtoken $NGROK_AUTH_TOKEN
    ports:
      - 4040:4040 # Web dashboard for ngrok

  zookeeper:
    image: confluentinc/cp-zookeeper:7.5.1
    container_name: zookeeper
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000

  broker:
    image: confluentinc/cp-kafka:7.5.1
    container_name: broker
    depends_on:
      - zookeeper
      - ngrok
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
      KAFKA_LISTENERS: DOCKER://broker:29092, NGROK://broker:9092
      KAFKA_ADVERTISED_LISTENERS: DOCKER://broker:29092
      KAFKA_INTER_BROKER_LISTENER_NAME: DOCKER
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: DOCKER:PLAINTEXT,NGROK:PLAINTEXT
      KAFKA_AUTO_CREATE_TOPICS_ENABLE: "true"
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_MIN_ISR: 1
      KAFKA_TRANSACTION_STATE_LOG_REPLICATION_FACTOR: 1
    entrypoint: 
      - /bin/sh 
      - -c 
      - |
        echo "Waiting for ngrok tunnel to be created"
        while : ; do
          curl_status=$$(curl -s -o /dev/null -w %{http_code} http://ngrok:4040/api/tunnels/command_line)
          echo -e $$(date) "\tTunnels API HTTP state: " $$curl_status " (waiting for 200)"
          if [ $$curl_status -eq 200 ] ; then
            break
          fi
          sleep 5 
        done
        echo "ngrok tunnel is up"
        # My kingdom for a jq 😿
        NGROK_LISTENER=$(curl -s  http://ngrok:4040/api/tunnels/command_line | grep -Po '"public_url":.*?[^\\]",' | cut -d':' -f2- | tr -d ',"' | sed 's/tcp:\/\//NGROK:\/\//g')
        echo $$NGROK_LISTENER
        export KAFKA_ADVERTISED_LISTENERS="$$KAFKA_ADVERTISED_LISTENERS, $$NGROK_LISTENER"
        echo "KAFKA_ADVERTISED_LISTENERS is set to " $$KAFKA_ADVERTISED_LISTENERS
        /etc/confluent/docker/run

  kcat:
    image: edenhill/kcat:1.7.1
    container_name: kcat
    restart: no
    entrypoint: tail -f /dev/null

networks:
  default:
     name: zaphod