farsightsec / go-config

Useful golang types for JSON, YAML config files.

Minimalist Go Config Library

The config package contains types useful for validating, parsing, and loading values of some useful types in config files. The config types generally embed a corresponding standard library type, and provide Unmarshaler and Marshaler support for loading configs from and saving configs to JSON and YAML formats.

The types in this package also implement flag.Value for use in command line arguments.

Types include:

• net/url.URL
• time.Duration
• net.{UDP,TCP,Unix}Addr
• crypto/tls.Config

All of these Unmarshal from and Marshal to their natural string representations, with the exception of tls.Config, which is represented in the configuration as a dictionary of filenames and other settings.

An additional utility String type holds a string value which can optionally be read from the environment or from a named file.

Example

import (
        "encoding/json"
        "github.com/farsightsec/go-config"
)

type Config struct {
        Server   config.URL
        Timeout  config.Duration
        Username config.String
        Key      config.String
}

// cfg.Server.URL = net/url.URL of Server.
// cfg.Timeout.Duration = time.Duration of Timeout.
var cfg Config

var serverURL config.URL

func init() {
        configText := `
        {
                "Server": "https://example.com:8080/api/",
                "Timeout": "90s",
                "Username": "$USER",
                "Key": "/etc/app/apikey"
        }`
        if err := json.Unmarshal([]byte(configText)); err != nil {
                panic(err)
        }

        flag.Var(&serverURL, "server", "URL for server")
}