## Compose sample application
### Go server with an Nginx proxy and a MySQL database

Project structure:
```
.
├── backend
│   ├── Dockerfile
│   ├── go.mod
│   └── main.go
├── db
│   └── password.txt
├── docker-compose.yaml
├── proxy
│   ├── conf
│   └── Dockerfile
└── README.md
```

[_docker-compose.yaml_](docker-compose.yaml)
```
services:
  backend:
    build: backend
    ...
  db:
    image: mysql:5.7
    ...
  proxy:
    build: proxy
    ports:
    - 80:80
    ...
```
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.

## Deploy with docker-compose

```
$ docker-compose up -d
Creating network "nginx-golang-mysql_default" with the default driver
Building backend
Step 1/8 : FROM golang:1.13-alpine AS build
1.13-alpine: Pulling from library/golang
...
Successfully built 5f7c899f9b49
Successfully tagged nginx-golang-mysql_proxy:latest
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-golang-mysql_db_1 ... done
Creating nginx-golang-mysql_backend_1 ... done
Creating nginx-golang-mysql_proxy_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
8906b14c5ad1        nginx-golang-mysql_proxy     "nginx -g 'daemon of…"   2 minutes ago       Up 2 minutes        0.0.0.0:80->80/tcp    nginx-golang-mysq
l_proxy_1
13e0e0a7715a        nginx-golang-mysql_backend   "/server"                2 minutes ago       Up 2 minutes        8000/tcp              nginx-golang-mysq
l_backend_1
ca8c5975d205        mysql:5.7                    "docker-entrypoint.s…"   2 minutes ago       Up 2 minutes        3306/tcp, 33060/tcp   nginx-golang-mysq
l_db_1
```

After the application starts, navigate to `http://localhost:80` in your web browser or run:
```
$ curl localhost:80
["Blog post #0","Blog post #1","Blog post #2","Blog post #3","Blog post #4"]
```

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