Docker环境下Express容器无法连接MongoDB的问题求助

问题描述 #

Docker新手搭建带用户登录功能的网站时，遇到Express服务器容器无法与MongoDB容器建立连接的问题，报错MongooseServerSelectionError: getaddrinfo ENOTFOUND mongodb。目前mongo-express管理页面可正常访问，但Express与MongoDB的连接始终失败。

相关配置与日志 #

docker-compose.yaml

services:
  express:
    container_name: video-express
    image: video-express:latest
    build:
      context: ./express
      dockerfile: Dockerfile.express
    ports:
      - "13000:3000"
    volumes:
      - video_express_node:/app/node_modules
      - ./express:/app
    tty: true
    stdin_open: true
    depends_on:
      - mongo
    networks:
      - default

  mongo:
    image: mongo:latest
    restart: always
    ports:
      - "27018:27017"
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: password
      MONGO_INITDB_DATABASE: q-cards-db
    volumes:
      - ./data/db:/database
    networks:
      - default
      - mongo-express

  mongo_express:
    image: mongo-express
    restart: always
    ports:
      - "8081:8081"
    environment:
      ME_CONFIG_MONGODB_ADMINUSERNAME: root
      ME_CONFIG_MONGODB_ADMINPASSWORD: password
      ME_CONFIG_MONGODB_SERVER: mongo
      # ME_CONFIG_BASICAUTH_USERNAME: admin
      # ME_CONFIG_BASICAUTH_PASSWORD: Password1
    depends_on:
      - mongo
    networks:
      - mongo-express

  dev:
    container_name: video-dev
    image: video-dev:latest
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "15173:5173"
    volumes:
      - video_dev_node_modules:/app/node_modules
      - .:/app
    depends_on:
      - express
    tty: true
    stdin_open: true
    networks:
      - default

networks:
  default:
    driver: bridge
  mongo-express:
    driver: bridge

volumes:
  video_dev_node_modules:
  video_express_node:

server.js连接代码

mongoose.connect("mongodb://root:pass@mongodb:27017/videoUserDB", {
  useNewUrlParser: true
});

错误日志

(node:7) [MONGODB DRIVER] Warning: Current Server Discovery and Monitoring engine is 
deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.
video-management-mongo_express-1  | Could not connect to database using connectionString: mongodb://root:password@mongo:27017/"
video-management-mongo_express-1  | (node:7) UnhandledPromiseRejectionWarning: MongoNetworkError: failed to connect to server [mongo:27017] on first connect [Error: connect ECONNREFUSED 172.19.0.2:27017
video-management-mongo_express-1  |     at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1144:16) {
video-management-mongo_express-1  |   name: 'MongoNetworkError'
video-management-mongo_express-1  | }]
video-management-mongo_express-1  |     at Pool.<anonymous> (/node_modules/mongodb/lib/core/topologies/server.js:441:11)


video-management-mongo_express-1  | Mongo Express server listening at http://0.0.0.0:8081
video-management-mongo_express-1  | Server is open to allow connections from anyone (0.0.0.0)
video-express                     | /app/node_modules/mongoose/lib/connection.js:824
video-express                     |   const serverSelectionError = new ServerSelectionError();
video-express                     |                                ^
video-express                     |
video-express                     | MongooseServerSelectionError: getaddrinfo ENOTFOUND mongodb
video-express                     |     at Connection.openUri (/app/node_modules/mongoose/lib/connection.js:824:32)
video-express                     |     at /app/node_modules/mongoose/lib/index.js:381:10
video-express                     |     at /app/node_modules/mongoose/lib/helpers/promiseOrCallback.js:41:5
video-express                     |     at new Promise (<anonymous>)
video-express                     |     at promiseOrCallback (/app/node_modules/mongoose/lib/helpers/promiseOrCallback.js:40:10)
video-express                     |     at Mongoose._promiseOrCallback (/app/node_modules/mongoose/lib/index.js:1234:10)
video-express                     |     at Mongoose.connect (/app/node_modules/mongoose/lib/index.js:380:20)
video-express                     |     at Object.<anonymous> (/app/server.js:50:10)
video-express                     |     at Module._compile (node:internal/modules/cjs/loader:1159:14)
video-express                     |     at Module._extensions..js (node:internal/modules/cjs/loader:1213:10) {
video-express                     |   reason: TopologyDescription {
video-express                     |     type: 'Unknown',
video-express                     |     servers: Map(1) {
video-express                     |       'mongodb:27017' => ServerDescription {
video-express                     |         address: 'mongodb:27017',
video-express                     |         type: 'Unknown',

问题定位 #

1. 主机名错误：Express连接字符串使用的主机名是mongodb，但docker-compose中MongoDB服务的名称为mongo，容器间通信必须以服务名作为主机名。
2. 密码不匹配：连接字符串中的密码是pass，但docker-compose配置的MongoDB root密码是password，认证信息不一致导致连接失败。
3. 数据库名称不一致：docker-compose初始化的数据库是q-cards-db，但连接字符串指定的是videoUserDB，若该库未提前创建，需确认MongoDB是否允许自动创建数据库。
4. 缺少必要连接选项：MongoDB驱动提示需添加useUnifiedTopology: true选项，否则会有弃用警告，也可能影响连接稳定性。

修复步骤 #

1. 修改Express连接字符串 #

将主机名改为mongo，密码改为password，同时添加useUnifiedTopology: true选项：

mongoose.connect("mongodb://root:password@mongo:27017/videoUserDB", {
  useNewUrlParser: true,
  useUnifiedTopology: true
});

若要使用初始化的q-cards-db，可将连接字符串中的videoUserDB替换为q-cards-db。

2. （可选）添加MongoDB健康检查 #

depends_on仅保证容器启动顺序，不等待MongoDB完全就绪。可在docker-compose的mongo服务中添加健康检查，确保Express在MongoDB就绪后再尝试连接：

mongo:
  # 其他配置保持不变
  healthcheck:
    test: ["CMD", "mongosh", "--eval", "db.adminCommand('ping')"]
    interval: 10s
    timeout: 5s
    retries: 5

同时修改express服务的depends_on配置，等待MongoDB健康检查通过：

express:
  # 其他配置保持不变
  depends_on:
    mongo:
      condition: service_healthy

3. 重启容器 #

执行以下命令重启所有容器，使配置生效：

docker-compose down
docker-compose up --build

内容的提问来源于stack exchange，提问作者koji tanaka