global var out out init.go in revel

(EDITING to fix capitalization and add context)

In revel's init.go, I have a global var: DB.

package app

import (
 "database/sql"
 "fmt"

 _ "github.com/go-sql-driver/mysql"
 "github.com/revel/revel"
)
var DB *sql.DB

func InitDB() {
 
 connstring := fmt.Sprintf("revel:revel@tcp(localhost:3336)/revel")

 var err error
 DB, err = sql.Open("mysql", connstring)
 if err != nil {
	revel.INFO.Println("DB Error", err)
 }

}

How do I get that db variable in the rest of the app? Specifically, I was going to use this var in the models.

To start, how would I get it to work in this controller?
controllers/app.go

package controller

func (c App) Index() revel.Result {
 rows, err := app.DB.Exec("SELECT * FROM test_table")
 //do something with rows
 return c.Render()
}

Revel makes you "roll your own db" so it's up to you where connections are made and how to implement them.

Your InitDB() function must setup a public variable, e.g. DB (meaning its name is capitalized) which you will then access via the package that it lives in.

So notice your app/init.go is inside of package app:

package app

var DB *sql.DB

func InitDB() { DB = .... }

In Go, when your application is running each package acts as a sort of "singleton" so that anywhere else in the application where you access:

app.DB

This will look for the variable called DB in the app package. And if you have already run InitDB() to connect to the database, then app.DB will allow all other packages to use the database.