Ettevõttesüsteemide integreerimine 2023/24 kevad

1. Creating a Docker Compose File (YAML) for a Spring Boot Project and PostgreSQL

Note: If you are not familiar with YAML, you can refer to YAML Ain't Markup Language

In this document, we will create a docker-compose setup using both Spring Boot application and PostgreSQL database. Note that PostgreSQL is already available as a Docker image in Docker hub, so we just need to pull it from there, you just need to select the version you need from there, I have chosen 14.

We assume you have already completed all the steps in 1. Creating a Dockerfile for a Spring Boot project, i.e., you have already created the image of the Spring Boot project.

In what follows, we will create the docker-compose.yml file which allows us to combine Spring Boot application and PostgreSQL database in this document.

1. Create a file named docker-compose.yml in the project root directory

2. Copy the following content into that file. Note. replace week3-docker2 with the name of your service.

# the version of the Docker compose
version: '3.8'
services:
  # our first service
  week3-docker2:
    build: .  #the location where it can find the Dockerfile to build this service
    # using the already built image of the Spring Boot project
    image: 'docker-week3:latest'  
    # if we want to build an image, we can use "build"
    # restarts the container if it stops. 
    restart: always
    # mapping local machine port along with port inside a docker container
    ports:
      - 8080:8080
    # Express dependency between services. 
    depends_on:
      - postgre_db
    # Allows adding environment variables
    environment:
      - spring.datasource.url=jdbc:postgresql://postgre_db:5432/esi2023
      # note that we have replaced the localhost with the name of the database service
      - spring.datasource.username=postgres
      - spring.datasource.password=postgres
  # our second service
  postgre_db:
    # we do not need a build command here because we will pull an already built image from docker hub
    image: "postgres:14"
    restart: always
    ports:
      - 5432:5432
    environment:
      - POSTGRES_PASSWORD=postgres
      - POSTGRES_ROOT_PASSWORD=postgres
      - POSTGRES_USER=postgres
      - POSTGRES_DB=esi2023
    #volumes:
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"] #checking the connection status of a PostgreSQL database server
      interval: 10s
      timeout: 5s
      retries: 5

Running Spring Boot Application and PostgreSQL Database Using Docker Compose

Now we have our docker-compose setup for this application.

1. Clean up your project by deleting /target folder. In the explorer bar of VSCode, expand Maven, expand the project, under lifecycle, run clean.

2. Converts our .java source code into a .jar and puts it into the /target folder. In the explorer bar of VSCode, expand Maven, expand the project, under lifecycle, run package.

3. Use the following command to build images in the docker-compose. yml file.

$ docker-compose build

4. Check how many containers are running now by using the following command

$ docker ps

5. Use the following command to run the whole setup using docker-compose, which will capture the docker-compose.yml and start running using the instructions given on that file.

$ docker-compose up

6. Check how many images there are (there should be 2 images) by using the following command

$ docker image ls 

7. Check again how many containers are running now by using the following command

$ docker ps

8. Test your application by sending some HTTP requests, everything should be working as expected

7. You can use the following command to stop docker-compose.

$ docker-compose down