I would like to make a memo for the time studying the Go language.

This memo is about the environment construction, but I think that I will be good enough to be able to make the development of API server in Go language later.

Why we make in Docker

Building an environment with Docker offers many benefits.

• You can easily build an environment with any OS
• Firmly secure because host OS and development application are isolated
• Easier deployment and testing
• Less software installed on host OS
• Docker is the best.

What is Docker in the first place?

A platform for handling container-type virtual environments.

You can create, distribute, and run something like a lightweight, fast-running virtual machine called a container.

Installing Docker

Windows and Mac can download the installer on the official page of docker hub.

• windows
• mac

Linux systems can be installed using apt-get or yum.

Environment construction

First, create a working directory on the terminal and move to there.

mkdir work
cd work

Make settings of Docker container

Docker can create container instances based on Docker images distributed at docker hub.

This time, instead of using the distributed Docker image as it is, I created a customized image using Dockerfile.

In addition, by using the tool called docker-compose, I can describe the settings from container build to integration in the file base of yml format (docker-compose.yml) and automate it.

Create Dockerfile and docker-compose.yml in the working directory.

Open the created file with your favorite editor and edit it.

• Dockerfile

FROM golang:latest
RUN mkdir /go/src/work
WORKDIR /go/src/work
ADD . /go/src/work

• docker-compose.yml

version: '3' 
services:
  app: 
    build: . 
    tty: true 
    volumes:
      - .:/go/src/work 

build

Create a container using the docker-compose command.

Run the following command in the working directory with Dockerfile, docker-compose

docker-compose build

Then, begin to create the Docker image composed of Docker file by docker-compose

If it completes successfully, an image file will be prepared and the Docker container can be launched.

You can check the prepared image file by the following command.

docker-compose images

Start Docker container

If we run the following command, will launch docker in the same directory

docker-compose up -d

It will be started in background by adding -d option.

You can check the container status with the following command.

docker-compose ps

Try implement

Let's write Hello, World! With Go and actually make it works

Create main.go file in host work and write the following code.

• main.go

package main

import "fmt"

func main () {
    fmt.Println ("Hello, World!")
}

The host's work directory is mounted on the container's work directory, so the created main.go can be accessed from the container.

You can execute main.go in the container environment by the following command.

docker-compose exec app go run main.go We can actually make an Herro, World!

It is also possible to enter and execute a container shell.

docker-compose exec app /bin/bash
go run main.go

Environment construction is complete!

If you share the source directory directly on Github, anyone with Docker can also easily build the environment.