Agfdhyk

I have a spring boot project which I'd like to containerize using docker.
I have a couple of spring boot applications which connect to same MySql server.

My spring applications requires the database to be completely setup (i.e. all the tables to be created and some data to be inserted in some of the tables) in order to start.

I am using Docker version 18.09.0 and docker-compose version 1.23.1 and ubuntu 16.04 LTS

I have two files create.sql and insert.sql, which I use to initialise the database to be used by the application.

I create the images using the command docker-compose.yml and it runs successfully and creates the images.

I have the following questions.

1. I assume when using docker-compose, a container starts as soon as all its dependent containers have started. Is there a way to wait for the mysql server to be up and ready to accept connections, before my API container gets started?




2. If I chose to create containers separately for the applications and mysql, and not use docker-compose, how do I make sure that my applications connect to the mysql container?




3. Is there any other tool which might help me achieve this?

Note:
I have tried to use docker inspect <container_id> to find the the IpAddress for the mysql container and use it to connect, but it doesn't work as well.

The following are the files I am using to create images.

docker-compose.yml file.

version: '3'



services:

  demo-mysql:

    image: demo-mysql

    build: ./demo-mysql

    volumes:

      - /mnt/data/mysql-data:/var/lib/mysql

    ports:

      - 3306:3306

    environment:

      - MYSQL_ROOT_PASSWORD=root

      - MYSQL_DATABASE=demo

      - MYSQL_PASSWORD=root



  demo-api:

    image: demo-api-1.0

    build: ./api

    depends_on:

      - demo-mysql

    ports:

      - 8080:8080

    environment:

      - DATABASE_HOST=demo-mysql

      - DATABASE_USER=root

      - DATABASE_PASSWORD=root

      - DATABASE_NAME=demo

      - DATABASE_PORT=3306



  demo1-app:

    image: demo1-app-1.0

    build: ./demo1

    depends_on:

      - demo-mysql

    ports:

      - 8090:8090

    environment:

      - DATABASE_HOST=demo-mysql

      - DATABASE_USER=root

      - DATABASE_PASSWORD=root

      - DATABASE_NAME=demo

      - DATABASE_PORT=3306

The following is the Dockerfile for the spring boot project

FROM java:8



VOLUME /tmp



ARG DATA_PATH=/src/main/resources

ARG APP_PORT=8080



EXPOSE ${APP_PORT}



ADD /build/libs/demo-api.jar demo-api.jar



ENTRYPOINT ["java","-jar","demo-api.jar"]

The following is the Dockerfile I used to create my mysql image

FROM mysql:5.7



ENV MYSQL_DATABASE=demo 

    MYSQL_USER=root 

    MYSQL_ROOT_PASSWORD=root



ADD ./1.0/create.sql /docker-entrypoint-initdb.d

ADD ./1.0/insert.sql /docker-entrypoint-initdb.d



EXPOSE 3306

Use the healthcheck feature of docker-compose (https://docs.docker.com/compose/compose-file/#healthcheck).
Something like this:

services:

  demo-mysql:

    image: demo-mysql

    build: ./demo-mysql

    volumes:

      - /mnt/data/mysql-data:/var/lib/mysql

    ports:

      - 3306:3306

    environment:

      - MYSQL_ROOT_PASSWORD=root

      - MYSQL_DATABASE=demo

      - MYSQL_PASSWORD=root

    healthcheck:

      test: ["CMD-SHELL", 'mysqladmin ping']

      interval: 10s

      timeout: 2s

      retries: 10

The depending containers will not start until the demo-mysql container is healthy