Load configuration from multiple sources in Go
Go
Latest commit d41df09 Dec 5, 2016 @cihangir cihangir committed on GitHub Merge pull request #55 from rjeczalik/flag-value
multiconfig: add partial support for flag.Value

README.md

Multiconfig GoDoc Build Status

Load configuration from multiple sources. Multiconfig makes loading/parsing from different configuration sources an easy task. The problem with any app is that with time there are many options how to populate a set of configs. Multiconfig makes it easy by dynamically creating all necessary options. Checkout the example below to see it in action.

Features

Multiconfig is able to read configuration automatically based on the given struct's field names from the following sources:

  • Struct tags
  • TOML file
  • JSON file
  • Environment variables
  • Flags

Install

go get github.com/koding/multiconfig

Usage and Examples

Lets define and struct that defines our configuration

type Server struct {
    Name    string `required:"true"`
    Port    int    `default:"6060"`
    Enabled bool
    Users   []string
}

Load the configuration into multiconfig:

// Create a new DefaultLoader without or with an initial config file
m := multiconfig.New()
m := multiconfig.NewWithPath("config.toml") // supports TOML and JSON

// Get an empty struct for your configuration
serverConf := new(Server)

// Populated the serverConf struct
err := m.Load(serverConf) // Check for error
m.MustLoad(serverConf)    // Panic's if there is any error

// Access now populated fields
serverConf.Port // by default 6060
serverConf.Name // "koding"

Run your app:

# Sets default values first which are defined in each field tag value. 
# Starts to load from config.toml
$ app

# Override any config easily with environment variables, environment variables
# are automatically generated in the form of STRUCTNAME_FIELDNAME
$ SERVER_PORT=4000 SERVER_NAME="koding" app

# Or pass via flag. Flags are also automatically generated based on the field
# name
$ app -port 4000 -users "gopher,koding"

# Print dynamically generated flags and environment variables:
$ app -help
Usage of app:
  -enabled=true: Change value of Enabled.
  -name=Koding: Change value of Name.
  -port=6060: Change value of Port.
  -users=[ankara istanbul]: Change value of Users.

Generated environment variables:
   SERVER_NAME
   SERVER_PORT
   SERVER_ENABLED
   SERVER_USERS

License

The MIT License (MIT) - see LICENSE for more details