Viper: Config export

[krzysztofantczak]

Hi,

How can i export loaded config (with ie. override some parts of it using ENV or CLI args) back to original or even different config file?

[cytec]

+1 option for writing config back to a file would be great

[cytec]

Nevermind, i've just wrote a simple function which saves everything to a file:

type config struct {
    DataDir      string
    Debug        bool
    Devel        bool
    ApiKey       string
    SnatchFolder string
    Port         int
    TvdbUrl      string
    TvdbKey      string
    LogJSON      bool
    FirstRun     bool
}

var C config

func saveConfig(cfgpath string) error {

    viper.Marshal(&C)

    b, err := json.MarshalIndent(C, "", "    ")
    if err != nil {
        return err
    }

    f, err := os.Create(cfgpath)
    if err != nil {
        return err
    }

    defer f.Close()

    f.WriteString(string(b))

    return nil
}

[theherk]

I feel like this would be a huge gain for viper. I would love to be able to modify the configuration and save it back. Viper already knows which file type was loaded and how to format that language.

[theherk]

Needing this feature, too, I have opened PR #287. Once complete, writing will be available.

[patrick-motard]

@theherk @spf13 It looks like this issue can be closed now that #287 is complete. Although it would be nice if the functionality was documented. I didn't see anything about it in the README.md.

[theherk]

Excellent point. I'll make sure the documentation for this feature set is ship shape this week.

[patrick-motard]

@theherk Thanks for the work you did on this feature. It saved me time writing my own!!

[koliyo]

Great to see this functionality available. But it is really missing from the main README.md!

[f1mishutka]

There is no viper.Marshal() method at https://github.com/spf13/viper/blob/master/viper.go

What am I doing wrong? :)

[mattouille]

There is no viper.Marshal() method at https://github.com/spf13/viper/blob/master/viper.go

What am I doing wrong? :)

I believe it's actually supposed to be viper.Unmarshal(). The idea being that you save everything to the struct (Unmarshal is a good way of getting the "final" values if you have multiple sources) and then writing it all to JSON.

[cytec]

@f1mishutka since my comment is from 2015 here's a link to the version i was using at the time: https://github.com/spf13/viper/blob/d8f2aa78d42b618f51e668d0b7e05fe203f889de/viper.go#L314 as you might see there are a shitload of changes made since then. I guess it has been renamed to Unmarshal but since WriteConfig has been implemented a while ago, id recommend using this instead ;)