Purpose of this repository

Know how to create a Go application, deploy to Heroku (automatically) and configure your domain to point the domain provided by Heroku.

Things you will learn

• Use Git and GitHub
• Create a simple Go backend server
• Use Docker
• Use Heroku platform
• DNS configuration

Requirements

• Go
• Heroku CLI
• Git
• Docker
• Domain (optional)

---

Instructions

Create a project in GitHub

1. Go to www.github.com and click "New"
2. Check Add README and Add .gitignore and select Go from the list

Configure your SSH keys for GitHub

Clone the repository

git clone git@github.com:<YOUR_USERNAME>/<YOUR_APP>.git

Write the code

We will write a simple server with single endpoint. The endpoint will be GET /ping and it will response a 200 OK status code and the message "pong". The folder structure will be:

|-cmd
| |-main.go         // Contains the entry point
|
|-internal
| |-router
|   |-router.go     // Contains the router initialization
|   |-endpoints.go  // Contains all the endpoints
|
|-defines
| |-paths.go        // Contains the paths of each endpoint

1. Init the module

   go mod init <YOUR_APP>
   

2. Download gin-gonic library

   go get -u github.com/gin-gonic/gin
   

Create the Dockerfile

1. Create a file with name Dockerfile in the root of the project with the following content

   # Use alpine (very lightweight linux distro) with Go installed as a base image
   FROM golang:rc-alpine3.14 AS builder
   
   # Create a folder called build
   RUN mkdir /build
   # Change the working directory to the new folder
   WORKDIR /build
   # Copy all the contents to the new folder
   COPY . .
   # Build binary
   RUN go build -o output ./cmd/main.go
   
   # Use alpine as a base image
   FROM alpine
   # Create a user
   RUN adduser -S -D -H -h /app appuser
   # Change current user
   USER appuser
   # Copy the binary created before to a new folder
   COPY --from=builder /build/output /app/
   # Change the working directory to the new folder
   WORKDIR /app
   # Execute the binary
   CMD ["./output"]

2. Build docker image

docker build -t <YOUR_APP> .

3. Run the image

docker run --rm -p 8080:8080 <YOUR_APP>

Create the project in Heroku

1. Go to Heroku Dashboard and click on New > New app
2. Go to Deploy tab > Deployment method > Github
3. Login with GitHub and search for <YOUR_APP>
4. Click on Connect
5. Click Enable Automatic Deploys

Configure your app to use containers

1. Login in Heroku CLI

   heroku login
   

2. Set stack to container

   heroku stack:set container --app <YOUR_APP>
   

Create the heroku.yml

1. Create a file with name heroku.yml in the root of the project with the following content

   build:
     docker:
       web: Dockerfile

Push your local changes

git add .
git commit -m "Initial version"
git push

Configure your app to point to your domain

---

Links