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node.jsmongodbdocker-composehealth-check

Docker compose - Check if mongodb port is available and only then start NodeJS container

I have a simple NodeJS app with connection to mongodb which are all started using docker compose. The problem it that if mongo is not initiated yet - NodeJS app throws an error that it cannot connect to mongodb:

nodejs-app  | Server running...
nodejs-app  | MongoNetworkError: failed to connect to server [mongo:27017] on first connect [Error: connect ECONNREFUSED 192.168.192.2:27017

When I restarting nodejs app manually - it connecting successfully as mongo already initialized:

nodejs-app  | Server running...
nodejs-app  | MongoDB Connected

My docker compose file:

version: '3.7' 
services: 
  mongo:
    container_name: mongo
    restart: always
    image: mongo:4.2.0 
    volumes:
      - ./data:/data/db
    ports: 
      - '27017:27017'   
    networks:
      - nodejs-mongo
  
  nodejs-app: 
    container_name: nodejs-app
    restart: always
    build: test-files 
    ports: 
      - '3000:3000'
    environment:
      - MONGO_PORT=27017 
    depends_on:
      - mongo
    networks:
      - nodejs-mongo

networks:
  nodejs-mongo:

My question is - how to check that mongo port available prior to starting nodejs-app container to suppress connection errors of nodejs-app?

Solution

  • Well, have done it this way in dockerfile, using docker-compose-wait:

    ## Add the wait script to the image
ADD https://github.com/ufoscout/docker-compose-wait/releases/download/2.8.0/wait /wait
RUN chmod +x /wait

## Launch the wait tool and then your application
CMD /wait && node index.js
COPY . /usr/src/app