README.md

Go Config

Package config provides support for configuration of go applications. It supports multiple configuration sources. Configuration variables can be defined only partially in a single source and multiple times in various sources. Value for the same variable will be applied from the source with the highest priority - added as last to the slice of providers.

The following configuration sources are currently provided out of the box:

• yaml
• env

It is possible to customize which internal source should be used for configuration. Additional custom sources can be configured and used with or without internal configuration providers.

YAML

Configuration file is parsed using go-yaml/yaml module. "config.yaml" file must be in the same directory as the application executable.
Struct tags supported by the go-yaml/yaml module can be used.

ENV

Environment variables should be named as uppercase field names, each nested struct name should be inserted with an underscore ("_") prefix and postfix.
Prefix of environment variables can be manually configured when env provider is initialized.
Default configuration overwrites yaml configuration with values from environment.

Usage

Default configuration

package main

import "github.com/tpodg/go-config"

func main() {
	cfg := struct {
		StringField  string
		IntField     int
		NestedStruct struct {
			NestedString string
		}
	}{
		StringField: "string value",
	}

	err := config.Parse(&cfg)
	if err != nil {
		// handle error
	}
}

Custom configuration

package main

import "github.com/tpodg/go-config"

func main() {
	cfg := struct {
		StringField string
		IntField    int
	}{}

	c := config.New()
	c.WithProviders(&pDummy{}, &config.Env{Prefix: "PREF"})

	err := c.Parse(&cfg)
	if err != nil {
		// handle error
	}
}

type pDummy struct{}

func (p *pDummy) Provide(config interface{}) error {
	// implementation
	return nil
}