Example project to get the hang of the Go language, Docker containers, continuous integration with CircleCI.

This is built on Ubuntu Xenial (16.04). On Windows/Mac some tweaks probably needed.

Build status:

Core Todo

• Docker hello world
• Hello http server
• Unit test case
• Development workflow with code reload/compile
• Make a HTTP-request
• Parse JSON
• CircleCI integration
• Production deployment
• Contiuous deployment

More Todo

• Use a goroutine
• Use a channel
• Use an HTML template
• Serve static files
• docker-compose.yml

Usage

Development

Assuming you have docker installed, clone this repo, cd to the project directory, build and run:

• $ docker build -t hello-golang .
• $ docker run --volume=$PWD:/go/src/app -p 8080:3000 --rm --name my-running-app hello-golang

You should see "Starting server..." in the console, and "Hello world" in your browser if you navigate to localhost:8080

build -t tags the container with the given name --volume mounts the current directory to the docker container for code reloading -p binds your host port to docker port --rm removes the container after exit --name assigns a name

If you modify the source code, you should see the changes when refreshing your browser window.

Deployment

To deploy the project using the image in Docker Hub registry

• install Docker on your server
• docker pull ahalla/golang-docker-circleci-example
• docker run -d -p 8080:3000 --rm --name golang-docker-circleci-example ahalla/golang-docker-circleci-example

This will run the container as a background job, listening to the OS port 8080. The container will be removed automatically when killed.

Contiuous deployment

To automatically update the running application, you can do something along the lines of:

#/bin/bash
echo "Pulling the latest version from registry"
docker pull ahalla/golang-docker-circleci-example
echo "Killing the running container"
docker kill golang-docker-circleci-example
echo "Preparing to run.."
docker run -d -p 8080:3000 --rm --name golang-docker-circleci-example ahalla/golang-docker-circleci-example

Here we give the container a name so we can kill it later. This script can be either triggered from the CI or run in cron for periodical updates (you should probably add a check whether a new version was actually pulled or not).

This is a naive solution, but probably enough to start with.

Technology links

• The Go Programming Language https://golang.org/
• Docker https://www.docker.com/
• CircleCI https://circleci.com/
• golang docker image https://hub.docker.com/_/golang/
• gin for code reloading https://github.com/codegangsta/gin

Tutorials

• Install Docker on Ubuntu 16.04 https://www.digitalocean.com/community/tutorials/how-to-install-and-use-docker-on-ubuntu-16-04
• Development with Go and Docker https://medium.com/developers-writing/docker-powered-development-environment-for-your-go-app-6185d043ea35