Flag or Env

A simple go module to manage flags and env variables, and get them as needed.

Supports Generics

Features

Get flags and environment variables
Specify default values
Specify a custom struct to fill
Specify preference, whichever value will be used first

Basic Usage

package main

import (
	"fmt"

	"github.com/maxkruse/flagorenv"
)

type ExampleStruct struct {
	StringField string `default:"my default string, as per the tag"`
	IntField    int64
	StrArr      []string
}

func main() {
	c, err := flagorenv.LoadFlagsOrEnv[ExampleStruct](&flagorenv.Config{
		Prefix:     "test",
		PreferFlag: true,
	})

	if err != nil {
		panic(err)
	}

	fmt.Printf("%+v\n", c)
}

And calling the program like such

TEST_INT_FIELD=420 go run example.go -test-int-field 69 -test-str-arr "hi,bye,good"

will result in the following output:

{StringField:my default string, as per the tag IntField:69 StrArr:[hi bye good]}

Installation

go get -u github.com/maxkruse/flagorenv

Behaviour

If you pass both the Environment-Variable and the Flag, the config's PreferFlag determines which value will be used.

If you pass only one of the two, the value will be used.

If you omit the value, the default value will be used. Either using go-default's tags, or Zero-initialized.

Limitations

As of right now, only the following types are supported, any others will log an error:

string
int64
float64
bool
[]string (separated by comma)

Dependencies

go-strcase For converting strings interally to either SNAKE_CASE (env vars) or kebab-case (flags)