env

README

What is it?

The env package is to simplify reading environment variables with e.g. the flag package.

Example:

In our main, we often allow users to initialize our programs via flags. When users leave out the flags, we want to fall back to environment variables. The env package simplifies this scenario.

import (
    "flag"
    "fmt"
)

func main() {
	var (
		// Parse addr from flag, use HTTP_ADDR and ADDR env vars as fallback
		addr = flag.String("addr", env.String("127.0.0.1:3000", "HTTP_ADDR", "ADDR"), "Bind to this address")
	)
	flag.Parse()

	fmt.Println(*addr)
	// Output: 127.0.0.1:3000
}

License

MIT. See LICENSE file.

Documentation

Overview

Package env simplifies reading values from environment variables.

It is typically used in the main function to initialize variables from the flag package, then fallback to using environment variables.

Example

package main

import (
	"flag"
	"fmt"

	"github.com/olivere/env"
)

func main() {
	var (
		// Parse addr from flag, use HTTP_ADDR and ADDR env vars as fallback
		addr = flag.String("addr", env.String("127.0.0.1:3000", "HTTP_ADDR", "ADDR"), "Bind to this address")
	)
	flag.Parse()

	fmt.Println(*addr)
}

Output:

127.0.0.1:3000

Index

• func Bool(defaultValue bool, envvars ...string) bool
• func Duration(defaultValue time.Duration, envvars ...string) time.Duration
• func Float32(defaultValue float32, envvars ...string) float32
• func Float64(defaultValue float64, envvars ...string) float64
• func Int(defaultValue int, envvars ...string) int
• func Int64(defaultValue int64, envvars ...string) int64
• func String(defaultValue string, envvars ...string) string
• func Time(defaultValue time.Time, layout string, envvars ...string) time.Time

Examples

• Package

Functions

func Bool

func Bool(defaultValue bool, envvars ...string) bool

Bool inspects the environment variables specified in envvars. If all of these environment variables are empty, it returns defaultValue.

func Duration

func Duration(defaultValue time.Duration, envvars ...string) time.Duration

Duration inspects the environment variables specified in envvars. If all of these environment variables are empty, it returns defaultValue.

func Float32

func Float32(defaultValue float32, envvars ...string) float32

Float32 inspects the environment variables specified in envvars. If all of these environment variables are empty, it returns defaultValue.

func Float64

func Float64(defaultValue float64, envvars ...string) float64

Float64 inspects the environment variables specified in envvars. If all of these environment variables are empty, it returns defaultValue.

func Int

func Int(defaultValue int, envvars ...string) int

Int inspects the environment variables specified in envvars. If all of these environment variables are empty, it returns defaultValue.

func Int64

func Int64(defaultValue int64, envvars ...string) int64

Int64 inspects the environment variables specified in envvars. If all of these environment variables are empty, it returns defaultValue.

func String

func String(defaultValue string, envvars ...string) string

String inspects the environment variables specified in envvars. If all of these environment variables are empty, it returns defaultValue.

func Time

func Time(defaultValue time.Time, layout string, envvars ...string) time.Time

Time inspects the environment variables specified in envvars. If all of these environment variables are empty, it returns defaultValue.