Part 7: Run from the Docker Hub images

Continued from previous blog

Previous blog tells about build, push image form local to an docker-hub.

In this we are going to see how to run form the docker image.

Steps :

$ mkdir pull-from-image
$ cd pull-from-image

Add docker-compose.yml and Docker file into directory

docker-compose.yml

version: "3"
services:
  app:
    build: .
    command: "bundle exec puma -p 3000 -e development -b unix:///var/run/puma.sock
   -C config/puma.rb"
    ports:
      - "3000:3000"
    volumes:
      - ./app/log:/app/log
    environment:
      - DB_USER_NAME=postgres
      - DB_HOST=localhost
      - DATABASE_NAME=db_name
      - DB_PASSWORD=password      
  bundle:
    # 'image' will vary depending on your docker-compose
    # project name. You may need to run `docker-compose build web`
    # before this works.
    image: ubuntu

Note: update the environment: with local database details

Docker

FROM pvin/docker_test:1.5
ENV APP_HOME /myapp
WORKDIR $APP_HOME

Note:
pvin/docker_test:1.5 => docker_id/remo_name:(version/tag)

/myapp => While creating the image of the app, name /myapp is used for keeping the all required file. example: RUN mkdir /myapp

Once all set run below listed comments

$ sudo docker-compose build                  #to build
$ sudo docker-compose run app bundle install #to install gems
$ sudo docker-compose up                     #to run the app 

hit the url localhost:3000 or 172.17.0.1:3000 which ever the IP address given in database.yml -> host : 172.17.0.1

Done ! you can see the landing page

One More important thing is use dotenv gem for setting up the user name and password from the ENV file. Because once image is made can’t be edit, so if we keep it as ENV variable and value can be set at .env file based on db.

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