danott / envflag

Set flags via environment variables.

package envflag

Set flags via environment variables.

Usage

Flags are still defined using the stdlib package "flag". The only change to your code is calling envflag.Parse() in place of flag.Parse().

If your flag wasn't set via command-line argument, an equivalent environment variable will be used.

Precedence is: command-line agrument, environment variable, default.

Example

package main

import (
	"flag"
	"log"

	"github.com/danott/envflag"
)

func main() {
	var i int
	flag.IntVar(&i, "port", 2112, "Run on this port.")
	envflag.Parse()
	log.Printf("port: %v", i)
}

Run your example to see the precedence in action:

go run main.go
go run main.go --port=2113
PORT=2114 go run main.go
PORT=2114 go run main.go --port=2113