go - Sharing a globally defined db conn with multiple packages

Question

I've read a few StackOverflow answers on how we handling the db connection. Since it's a pool, we can define it globally and use it in multiple goroutines and it's safe.

The issue I'm having is that I have split my REST API into multiple packages. Each of these packages require a db connection, so I open a database connection in the startup. But even if I define the connection globally, it's only at the package level. What can I do to potentially share it among multiple packages?

For some context I'm using the PostgreSQL driver and gin-gonic in my application.

question from:https://stackoverflow.com/questions/31218008/sharing-a-globally-defined-db-conn-with-multiple-packages

Answer 1

There is also the option of creating another package to hold your database connection-related settings. It can then have a package level global, which can be initialized in main and used in any package that is importing it.

This way, you can explicitly see that the database package is being imported. Here is some sample code.

package database

var (
    // DBCon is the connection handle
    // for the database
    DBCon *sql.DB
)

---

package main

import "myApp/database"

func main() {

    var err error
    database.DBCon, err = sql.Open("postgres", "user=myname dbname=dbname sslmode=disable")

}

---

package user

import "myApp/database"

func Index() {
    // database handle is available here
    database.DBCon

    ...
}