Docker Compose to open MongoDB container to open MongoDB server from localhost using Robo 3T.

docker-compose.yml

version: "3.8"
services:
  mongodb:
    image: mongo
    container_name: mongodb
    restart: always
    ports:
      - 27018:27017
    volumes:
      - ./data:/data/db
    environment:
      - MONGO_INITDB_ROOT_USERNAME=user
      - MONGO_INITDB_ROOT_PASSWORD=pass
    expose:
      - 27018
    command: --quiet

  mongo-express:
    image: mongo-express
    container_name: mongo-express
    restart: always
    ports:
      - 8081:8081
    environment:
      - ME_CONFIG_MONGODB_ADMINUSERNAME=user
      - ME_CONFIG_MONGODB_ADMINPASSWORD=pass
      - ME_CONFIG_MONGODB_SERVER=mongodb

networks:
  default:
    name: mongodb_network