## Compose sample application ### Java application with Spring framework and a Postgres database Project structure: ``` . ├── backend │   ├── Dockerfile │   └── ... ├── db │   └── password.txt ├── compose.yaml └── README.md ``` [_compose.yaml_](compose.yaml) ``` services: backend: build: backend ports: - 8080:8080 db: image: postgres ... ``` The compose file defines an application with two services `backend` and `db`. When deploying the application, docker compose maps port 8080 of the backend service container to port 8080 of the host as specified in the file. Make sure port 8080 on the host is not already being in use. ## Deploy with docker compose ``` $ docker compose up -d Creating network "spring-postgres_default" with the default driver Building backend Step 1/11 : FROM maven:3.5-jdk-9 AS build 3.5-jdk-9: Pulling from library/maven ... Successfully tagged spring-postgres_backend:latest WARNING: Image for service backend was built because it did not already exist. To rebuild this image you must use `docker-compose build` or `docker-compose up --build`. Creating spring-postgres_backend_1 ... done Creating spring-postgres_db_1 ... done ``` ## Expected result Listing containers must show two containers running and the port mapping as below: ``` $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 56236f640eaa postgres "docker-entrypoint.s…" 29 seconds ago Up 28 seconds 5432/tcp spring-postgres_db_1 6e69472dc2c0 spring-postgres_backend "java -Djava.securit…" 29 seconds ago Up 28 seconds 0.0.0.0:8080->8080/tcp spring-postgres_backend_1 ``` After the application starts, navigate to `http://localhost:8080` in your web browse or run: ``` $ curl localhost:8080 Getting Started: Serving Web Content

Hello from Docker!

``` Stop and remove the containers ``` $ docker compose down Stopping spring-postgres_db_1 ... done Stopping spring-postgres_backend_1 ... done Removing spring-postgres_db_1 ... done Removing spring-postgres_backend_1 ... done Removing network spring-postgres_default ```