Golang viper, I can't get fields after MergeConfigMap

Question

I'm working on Go project where I need to set up some configurations and for that I am using Viper. When I merge map with viper object I can't get individual config fields after, however when I do viper.AllSettings() I do get all the settings, for example:

package main

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

type config map[string]interface{}

func defaultConfig() config {
    return config{
        "prod": false,
        "amqp": config{
            "url":      "url",
            "workers":  2,
        },
        "log": config{
            "filename": "viperConfig",
        },
    }
}

func init() {
    conf := defaultConfig()
    if err := viper.MergeConfigMap(conf); err != nil {
        panic(err)
    }
    fmt.Println(viper.AllSettings())
    fmt.Println(viper.GetString("log.filename"))
}

func main() {
    // Some code here...
}

Output:

map[amqp:map[url:url workers:2] log:map[filename:viperConfig] prod:false]
// viperConfig is not printed out

Answer 1

Field "log" is a map in your config. You should be able to access its entries through GetStringMapString.

func init() {
    conf := defaultConfig()
    if err := viper.MergeConfigMap(conf); err != nil {
        panic(err)
    }
    fmt.Println(viper.AllSettings())
    fmt.Println(viper.GetStringMapString("log")["filename"])
}