https://github.com/antham/envh

Go helpers to manage environment variables
https://github.com/antham/envh

configuration-management environment golang tree

Last synced: 14 days ago
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Go helpers to manage environment variables

• Host: GitHub
• URL: https://github.com/antham/envh
• Owner: antham
• License: mit
• Created: 2017-01-12T11:25:48.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2024-11-26T06:59:22.000Z (5 months ago)
• Last Synced: 2025-03-29T03:11:20.869Z (21 days ago)
• Topics: configuration-management, environment, golang, tree
• Language: Go
• Homepage:
• Size: 113 KB
• Stars: 100
• Watchers: 4
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
# Envh [![codecov](https://codecov.io/gh/antham/envh/branch/master/graph/badge.svg)](https://codecov.io/gh/antham/envh) [![Go Report Card](https://goreportcard.com/badge/github.com/antham/envh)](https://goreportcard.com/report/github.com/antham/envh) [![GoDoc](https://godoc.org/github.com/antham/envh?status.svg)](http://godoc.org/github.com/antham/envh) [![GitHub tag](https://img.shields.io/github/tag/antham/envh.svg)]()

This library is made up of two parts :

- Env object : it wraps your environments variables in an object and provides convenient helpers.

- Env tree object : it manages environment variables through a tree structure to store a config the same way as in a yaml file or whatever format allows to store a config hierarchically

## Install

    go get github.com/antham/envh

## How it works

Check [the godoc](http://godoc.org/github.com/antham/envh), there are many examples provided.

## Example with a tree dumped in a config struct

```go

package envh

import (

	"encoding/json"

	"fmt"

	"os"

	"strings"

)

type CONFIG2 struct {

	DB struct {

		USERNAME   string

		PASSWORD   string

		HOST       string

		NAME       string

		PORT       int

		URL        string

		USAGELIMIT float32

	}

	MAILER struct {

		HOST     string

		USERNAME string

		PASSWORD string

		ENABLED  bool

	}

	MAP map[string]string

}

func (c *CONFIG2) Walk(tree *EnvTree, keyChain []string) (bool, error) {

	if setter, ok := map[string]func(*EnvTree, []string) error{

		"CONFIG2_DB_URL": c.setURL,

		"CONFIG2_MAP":    c.setMap,

	}[strings.Join(keyChain, "_")]; ok {

		return true, setter(tree, keyChain)

	}

	return false, nil

}

func (c *CONFIG2) setMap(tree *EnvTree, keyChain []string) error {

	datas := map[string]string{}

	keys, err := tree.FindChildrenKeys(keyChain...)

	if err != nil {

		return err

	}

	for _, key := range keys {

		value, err := tree.FindString(append(keyChain, key)...)

		if err != nil {

			return err

		}

		datas[key] = value

	}

	c.MAP = datas

	return nil

}

func (c *CONFIG2) setURL(tree *EnvTree, keyChain []string) error {

	datas := map[string]string{}

	for _, key := range []string{"USERNAME", "PASSWORD", "HOST", "NAME"} {

		value, err := tree.FindString("CONFIG2", "DB", key)

		if err != nil {

			return err

		}

		datas[key] = value

	}

	port, err := tree.FindInt("CONFIG2", "DB", "PORT")

	if err != nil {

		return err

	}

	c.DB.URL = fmt.Sprintf("jdbc:mysql://%s:%d/%s?user=%s&password=%s", datas["HOST"], port, datas["NAME"], datas["USERNAME"], datas["PASSWORD"])

	return nil

}

func ExampleStructWalker_customFieldSet() {

	os.Clearenv()

	setEnv("CONFIG2_DB_USERNAME", "foo")

	setEnv("CONFIG2_DB_PASSWORD", "bar")

	setEnv("CONFIG2_DB_HOST", "localhost")

	setEnv("CONFIG2_DB_NAME", "my-db")

	setEnv("CONFIG2_DB_PORT", "3306")

	setEnv("CONFIG2_DB_USAGELIMIT", "95.6")

	setEnv("CONFIG2_MAILER_HOST", "127.0.0.1")

	setEnv("CONFIG2_MAILER_USERNAME", "foo")

	setEnv("CONFIG2_MAILER_PASSWORD", "bar")

	setEnv("CONFIG2_MAILER_ENABLED", "true")

	setEnv("CONFIG2_MAP_KEY1", "value1")

	setEnv("CONFIG2_MAP_KEY2", "value2")

	setEnv("CONFIG2_MAP_KEY3", "value3")

	env, err := NewEnvTree("^CONFIG2", "_")

	if err != nil {

		return

	}

	s := CONFIG2{}

	err = env.PopulateStruct(&s)

	if err != nil {

		return

	}

	b, err := json.Marshal(s)

	if err != nil {

		return

	}

	fmt.Println(string(b))

	// Output:

	// {"DB":{"USERNAME":"foo","PASSWORD":"bar","HOST":"localhost","NAME":"my-db","PORT":3306,"URL":"jdbc:mysql://localhost:3306/my-db?user=foo\u0026password=bar","USAGELIMIT":95.6},"MAILER":{"HOST":"127.0.0.1","USERNAME":"foo","PASSWORD":"bar","ENABLED":true},"MAP":{"KEY1":"value1","KEY2":"value2","KEY3":"value3"}}

}

```