无法在Google App Engine中使用MySQL Go驱动程序

I am trying to get my app to connect to local MySQL db. I am importing the necessary packages in a file that defines a function to initialize the connection

import (
    "database/sql"
    _ "github.com/go-sql-driver/mysql"
)

The github.com/go-sql-driver/mysql is only imported once in the project and I believe that means its init is only called once. However, whenever I start my app with goapp serve I keep getting

Register called twice for driver mysql

I do not know what's causing this. I know where the offending line is but I am not sure how the Register() method gets called twice. My suspicion is that, because goapp refreshes your app when there is changes, it calls init() again and again causing the Register() to get called twice.

Anyone has ever seen this behavior before?

Your code may be importing two different mysql packages. Are you sure you aren't pulling in some package from elsewhere?