Goal

To create an environment for Golang and MySQL, and getting data from database via go application.

Directory Structure

on_your_computer

Docker/
　├ Go/
　│　└ Dockerfile
　└ MySQL/
　 　└ Dockefile
　　 └ test.sql

Create files

docker-compose.yml

version: '3'
services:
  db:
    build:
      context: ./MySQL
    environment:
      MYSQL_ROOT_PASSWORD: root
      MYSQL_DATABASE: test_db
      MYSQL_USER: docker
      MYSQL_PASSWORD: docker
    container_name: golang_db
    ports:
      - "3306:3306"
    tty: true
  app:
    build:
      context: ./Go
    volumes:
      - "./Go:/go"
    container_name: golang_app
    ports:
      - "8080:8080"
    tty: true
    depends_on:
      - db

Go/Dockerfile

FROM golang:latest

RUN apt-get update
RUN apt-get install vim -y
RUN go get "github.com/go-sql-driver/mysql"

MySQL/Dockerfile

FROM mysql:5.6
COPY test.sql /docker-entrypoint-initdb.d/test.sql

MySQL/test.sql

Use test_db;

Create table `test_tb` (id int, name varchar(20));

Insert into test_tb (id, name) values (1, 'test-user');

Then run command below

docker-compose up --build

How to use

You can edit main.go at local or docker container (golang_app)

get_into_docker_container

docker exec -it golang_app bash

main.go

package main
  
import(
        _ "github.com/go-sql-driver/mysql"
        "database/sql"
        "fmt"
        "log"
)

func main() {
        cnn, err := sql.Open("mysql", "docker:docker@tcp(db:3306)/test_db")
        if err != nil {
                log.Fatal(err)
        }

        id := 1
        var name string

        if err := cnn.QueryRow("SELECT name FROM test_tb WHERE id = ? LIMIT 1", id).Scan(&name); err != nil {
                log.Fatal(err)
        }

        fmt.Println(id, name)
}

Build & Run

on_golang_app_container

go run main.go

or

on_your_computer

docker exec -it golang_app bash -c "go run main.go"

you can get line below

1 test-user

Refs

https://github.com/docker-library/mysql/issues/129#issuecomment-178265632
https://hub.docker.com/_/mysql/