毒蛇，无法获取函数外部初始化的值

I have a problem using a viper, I have assigned variable by viper method, so when I try to get value inside any function I have a null value. Does anybody have any idea why does it happen so? Any other variables initialization works fine, but not viper GetString method.

Structure: main.go

    package main

    import (
        "project/Model"
        "github.com/spf13/viper"
        ...
    )

    func main() {
        //Config handling
        viper.SetConfigName("main")
        viper.AddConfigPath("/config/")
        err = viper.ReadInConfig()
        ...
    }

Package Model

    package Model

    import ("github.com/spf13/viper"
        ...
    )

    var sqlhost = viper.GetString("db.host")

    func foo() {
        log.Println(sqlhost)
    }    

I suspect that doing package variable initialization as you show will lead to the viper configuration not being complete before performing the GetString(), and therefore the zero (empty) string value is what is returned. Without seeing how you initialize your viper config, I'm guessing that it's not in an init() function, but is in a main() function that hasn't run yet when the package variable is assigned.

You should probably retrieve the viper.GetString("db.host") inside the highest level function that needs it rather than during package initialization.