Well, Now we're getting complicated. Hardcoded values for a database are kinda useless right? Lets load some JSON configs.

app.go

var config *Configuration // A global we'll reuse for the application

// Defining the structure of the JSON as we'll expect it
type Configuration struct { 
  Port        int     // Port the app is served on
  Db_Type     string
  Db_Username string
  Db_Password string
  Db_Host     string
  DB          string
}

// Loads configurations from a JSON file in a config directory relative to the app
func loadConfig() {
  file, err := ioutil.ReadFile("config/config.json")
  if err != nil {
    log.Fatal("unable to open config: ", err)
  }
  
  temp := new(Configuration) // Get a pointer to an instance with new keyword
  // Unmarshal is going to decode and store into temp
  if err := json.Unmarshal(file, temp); err != nil { 
    log.Fatal("unable to marshal JSON: ", err)
  }
  
  config = temp
}