connection refused with go&mysql&docker - mysql

Question

I'm trying to connect mysqlDB which is created on Docker from my local go file.
main.go
package main
import (
"database/sql"
"fmt"
_ "github.com/go-sql-driver/mysql"
)
func main() {
fmt.Println("Hello")
// All following 4 codes won't connect to the database.
// "db01" is docker container name. "test" is db name.
// db, err := sql.Open("mysql", "root:password#tcp(localhost:3306)/test")
// db, err := sql.Open("mysql", "root:password#tcp(localhost)/test")
// db, err := sql.Open("mysql", "root:password#tcp(db01)/test")
db, err := sql.Open("mysql", "root:password#tcp(db01:3306)/test")
if err != nil {
fmt.Println(err)
}
defer db.Close()
fmt.Println(db)
err = db.Ping()
if err != nil {
fmt.Println(err)
}
}
docker command
docker run --name db01 -dit -e MYSQL_ROOT_PASSWORD=password mysql:latest
error message
when trying with localhost:3306
dial tcp [::1]:3306: connect: connection refused
when trying with db01
dial tcp: lookup db01: no such host
mysql db is created on docker container without any issue, so I think connection between go file and docker container is not going well.
Do I have to create docker-compose.yml file?
I want to connect without it at now.
Thank you.

Answer 1

You created a docker container and ran MySQL in it. That container will have its own network address. You can publish a port of that container on your localhost by running:
docker run --name db01 -p 3306:3306 -dit -e MYSQL_ROOT_PASSWORD=password mysql:latest
This will publish the port 3306 of the container on localhost:3306. Then you can connect to it.
Alternatively, you can get the IP address of the container running using docker inspect <containerId>, and connect to that address:3306.