Docker-compose：如何连接到mongo容器

Question

I am trying to run my simple Ruby app in Docker container (I am a Windows 10 user). This is just a bunch of Ruby and bash scripts that operate on Mongo database. I am using docker-compose to compose 3 containers - one for mongo database (using official mongo image), one for my app and one to populate the database.

Then I run docker-compose build and docker-compose up commands. Mongo wakes up fine and it accepts data import. Then I open another Powershell window and run docker run -it <name> /bin/bash to get an interactive shell and run my script. Unfortunately, they can't connect to mongo for some reason.

My connection string looks like this:

@client = Mongo::Client.new([ 'mongodb:27017' ], :database => 'test')

I tried different versions of it, like mongodb , mongodb://mongodb:27017 , mongodb://mongo:27017' but nothing seems to work. When I run my script it runs for several seconds and then gives an error on the first line where I perform any operation on the database. Mongo doesn't show any connection attempts.

What am I doing wrong?

Dockerfile

FROM ruby:2.5
WORKDIR /usr/src/app
COPY Gemfile Gemfile.lock ./
RUN bundle install
COPY . .

Mongo-seed Dockerfile

FROM mongo
COPY test.csv /test.csv
CMD mongoimport --host mongodb -d test -c places --type csv --file /test.csv --headerline

docker-compose.yml

version: '3'
services:
  mongodb:
    container_name: mongodb
    image: mongo:latest
    volumes:
      - mongodata:/data/db
    ports:
      - 27017:27017
  web:
    build: .
    volumes:
      - .:/myapp
    ports:
      - "3000:3000"
    links:
      - mongodb
    depends_on:
      - mongodb
    tty: true
  mongo-seed:
    build: ./mongo-seed
    links:
      - mongodb
volumes:
  mongodata:

Answer 1

Instead of spawning a new container with docker run connect to the shell of the already running one with docker exec -ti <name> bash . Now you should be able to ping your database with ping mongodb or to execute your script.

The reason for this is that the new container you create isn't spawned in the same network as your database.

https://docs.docker.com/compose/networking/ https://docs.docker.com/engine/reference/commandline/network_connect/