docker-minecraft-server/examples/docker-compose-ngrok.yml

services:
  mc:
    image: itzg/minecraft-server
    tty: true
    stdin_open: true
    ports:
      - "25565:25565"
    environment:
      EULA: "TRUE"
    restart: unless-stopped
    volumes:
      # attach the relative directory 'data' to the container's /data path
      - ./data:/data

  ngrok:
    image: ngrok/ngrok:latest
    command:
      - "tcp"
      - "mc:25565"
    environment:
      NGROK_AUTHTOKEN: <YourAuthTokenHere>
    ports:
      - 4551:4551