## Compose sample application
### Python/Flask with Nginx proxy and MySQL database

Project structure:
```
.
├── compose.yaml
├── flask
│   ├── Dockerfile
│   ├── requirements.txt
│   └── server.py
└── nginx
    └── nginx.conf

```

[_compose.yaml_](compose.yaml)
```
services:
  backend:
    build:
      context: backend
      target: builder
    ...
  db:
    # We use a mariadb image which supports both amd64 & arm64 architecture
    image: mariadb:10-focal
    # If you really want to use MySQL, uncomment the following line
    #image: mysql:8
    ...
  proxy:
    build: proxy
    ...
```
The compose file defines an application with three services `proxy`, `backend` and `db`.
When deploying the application, docker compose maps port 80 of the proxy service container to port 80 of the host as specified in the file.
Make sure port 80 on the host is not already being in use.

> ℹ️ **_INFO_**  
> For compatibility purpose between `AMD64` and `ARM64` architecture, we use a MariaDB as database instead of MySQL.  
> You still can use the MySQL image by uncommenting the following line in the Compose file   
> `#image: mysql:8`

## Deploy with docker compose

```
$ docker compose up -d
Creating network "nginx-flask-mysql_default" with the default driver
Pulling db (mysql:8.0.19)...
5.7: Pulling from library/mysql
...
...
WARNING: Image for service proxy was built because it did not already exist. To rebuild this image you must use `docker-compose build` or `docker-compose up --build`.
Creating nginx-flask-mysql_db_1 ... done
Creating nginx-flask-mysql_backend_1 ... done
Creating nginx-flask-mysql_proxy_1   ... done
```

## Expected result

Listing containers should show three containers running and the port mapping as below:
```
$ docker compose ps
NAME                          COMMAND                  SERVICE             STATUS              PORTS
nginx-flask-mysql-backend-1   "flask run"              backend             running             0.0.0.0:8000->8000/tcp
nginx-flask-mysql-db-1        "docker-entrypoint.s…"   db                  running (healthy)   3306/tcp, 33060/tcp
nginx-flask-mysql-proxy-1     "nginx -g 'daemon of…"   proxy               running             0.0.0.0:80->80/tcp
```

After the application starts, navigate to `http://localhost:80` in your web browser or run:
```
$ curl localhost:80
<div>Blog post #1</div><div>Blog post #2</div><div>Blog post #3</div><div>Blog post #4</div>
```

Stop and remove the containers
```
$ docker compose down
```

## Use with Docker Development Environments

You can use this sample with the Dev Environments feature of Docker Desktop.

![Screenshot of creating a Dev Environment in Docker Desktop](../dev-envs.png)

To develop directly on the services inside containers, use the HTTPS Git url of the sample:
```
https://github.com/docker/awesome-compose/tree/master/nginx-flask-mysql
```