goenv

README

goenv

The goenv is used to map environment variables to go struct.

Installation

go get -u github.com/proproto/goenv

Example

type MySQLConfig struct {
	Host     string        `env:"MYSQL_HOST,default=localhost:3306"`
	User     string        `env:"MYSQL_USER,default=root"`
	Password string        `env:"MYSQL_PASSWORD"`
	Database string        `env:"MYSQL_DATABASE,required"`
	Timeout  time.Duration `env:"MYSQL_TIMEOUT,default=10s"`
	TLS      bool          `env:"MYSQL_TLS_ENABLED"`
	MaxConns int           `env:"MYSQL_MAX_CONNS"`
}

os.Clearenv()
os.Setenv("MYSQL_PASSWORD", "db_password")
os.Setenv("MYSQL_DATABASE", "db_name")
os.Setenv("MYSQL_TLS_ENABLED", "true")
os.Setenv("MYSQL_MAX_CONNS", "32")

config := MySQLConfig{}
goenv.MustBind(&config)

fmt.Printf("Host: %s\n", config.Host)
fmt.Printf("User: %s\n", config.User)
fmt.Printf("Password: %s\n", config.Password)
fmt.Printf("Database: %s\n", config.Database)
fmt.Printf("Timeout: %v\n", config.Timeout.String())
fmt.Printf("TLS: %v\n", config.TLS)
fmt.Printf("MaxConns: %v\n", config.MaxConns)
// Output:
// Host: localhost:3306
// User: root
// Password: db_password
// Database: db_name
// Timeout: 10s
// TLS: true
// MaxConns: 32

Documentation

Index

• Variables
• func Bind(dst interface{}) error
• func MustBind(dst interface{})
• type Binder
  • func (b *Binder) Bind(dst interface{}) error

Examples

• Bind
• Bind (Error)
• MustBind

Variables

var DefaultBinder = &Binder{TagKey: "env"}

DefaultBinder uses `env` as TagKey

Functions

func Bind

func Bind(dst interface{}) error

Bind binds environment variables to dst by DefaultBinder

Example

package main

import (
	"fmt"
	"os"
	"time"

	"github.com/proproto/goenv"
)

func main() {
	type config struct {
		Host         string        `env:"HOST,required"`
		Skip         string        `env:"-"`
		ReadTimeout  time.Duration `env:""`
		WriteTimeout time.Duration
	}

	os.Clearenv()
	os.Setenv("HOST", "0.0.0.0")
	os.Setenv("SKIP", "SHOULD_NOT_PRESENT")
	os.Setenv("READ_TIMEOUT", "1s")
	os.Setenv("WRITE_TIMEOUT", "2s")

	c := config{}
	err := goenv.Bind(&c)

	fmt.Println("err:", err)
	fmt.Println("Host:", c.Host)
	fmt.Printf("Skip: '%s'\n", c.Skip)
	fmt.Println("ReadTimeout:", c.ReadTimeout.String())
	fmt.Println("WriteTimeout:", c.WriteTimeout.String())
}

Output:
err: <nil>
Host: 0.0.0.0
Skip: ''
ReadTimeout: 1s
WriteTimeout: 2s

Example (Error)

package main

import (
	"fmt"
	"os"

	"github.com/proproto/goenv"
)

func main() {
	type config struct {
		Host string `env:"HOST,required"`
	}

	os.Clearenv()

	c := config{}
	err := goenv.Bind(&c)

	fmt.Println(err)
}

Output:
goenv: HOST not set

func MustBind

func MustBind(dst interface{})

MustBind binds environment variables to dst by DefaultBinder if fails, it would panic

Example

package main

import (
	"fmt"
	"os"
	"time"

	"github.com/proproto/goenv"
)

func main() {
	type MySQLConfig struct {
		Host     string        `env:"MYSQL_HOST,default=localhost:3306"`
		User     string        `env:"MYSQL_USER,default=root"`
		Password string        `env:"MYSQL_PASSWORD"`
		Database string        `env:"MYSQL_DATABASE,required"`
		Timeout  time.Duration `env:"MYSQL_TIMEOUT,default=10s"`
		TLS      bool          `env:"MYSQL_TLS_ENABLED"`
		MaxConns int           `env:"MYSQL_MAX_CONNS"`
	}

	config := MySQLConfig{}

	os.Clearenv()
	os.Setenv("MYSQL_PASSWORD", "db_password")
	os.Setenv("MYSQL_DATABASE", "db_name")
	os.Setenv("MYSQL_TLS_ENABLED", "true")
	os.Setenv("MYSQL_MAX_CONNS", "32")

	goenv.MustBind(&config)

	fmt.Printf("Host: %s\n", config.Host)
	fmt.Printf("User: %s\n", config.User)
	fmt.Printf("Password: %s\n", config.Password)
	fmt.Printf("Database: %s\n", config.Database)
	fmt.Printf("Timeout: %v\n", config.Timeout.String())
	fmt.Printf("TLS: %v\n", config.TLS)
	fmt.Printf("MaxConns: %v\n", config.MaxConns)
}

Output:
Host: localhost:3306
User: root
Password: db_password
Database: db_name
Timeout: 10s
TLS: true
MaxConns: 32

Types

type Binder

type Binder struct {
	// TagKey specifies the tag key while calling reflect.Field.Tag.Lookup(string)
	TagKey string
}

Binder struct

func (*Binder) Bind

func (b *Binder) Bind(dst interface{}) error

Bind binds environment variables to dst