README for Autobind

[](https://godoc.org/github.com/hierynomus/autobind)

Autobind is a library that can use Golang struct annotations to automatically bind Viper and Cobra flags to struct fields.

It is inspired by the excellent work of @spf13 on Viper and Cobra.

Installation

Installing Autobind is as simple as running:

go get github.com/hierynomus/autobind

Usage

    package main

    import (
        "github.com/hierynomus/autobind"
        "github.com/spf13/cobra"
        "github.com/spf13/viper"
    )

    type Config struct {
        Host string `cobra:"host" env:"HOST" viper:"host" default:"localhost"`
        Port int    `cobra:"port" env:"PORT" viper:"port" default:"8080"`
    }

    func main() {
        var config Config

        vp := viper.New()
        vp.SetConfigName("config")
        vp.AddConfigPath(".")
        vp.SetConfigType("yaml")
        if err := vp.ReadInConfig(); err != nil {
            if _, ok := err.(viper.ConfigFileNotFoundError); ok {
                logger.Warn().Msg("No config file found... Continuing with defaults")
                // Config file not found; ignore error if desired
            } else {
                fmt.Printf("%s", err)
                os.Exit(1)
            }
        }

        cmd := &cobra.Command{
            Run: func(cmd *cobra.Command, args []string) {
                // Do something with config
            },
        }

        binder := &autobind.Autobinder{
            ConfigObject: &config,
            Viper: vp,
            EnvPrefix: "MYAPP",
        }

        binder.Bind(context.Background(), cmd, []string{})

        cmd.Execute()
    }

Configuration

The following items can be set on the Autobind struct:

Name	Description
ConfigObject	The (pointer to the) struct that should be bound to the flags and environment variables.
Viper	The instantiated Viper instace.
UseNesting	Whether to use nested keys in Viper if encountering a sub-struct in the config object.
EnvPrefix	The prefix to use for environment variables.
SetDefaults	Whether to set the default values on config object.
Casters	A map of custom cast functions to use for specific types.