envutil

README

envutil - A utility library for environment variables

envutil is a tiny Golang library with some utility functions for dealing with environment variables. It basically exists because I kept copying the same utility code into my Golang libraries and applications and wanted to lib-ify this stuff instead of duplicating it.

WithDefault Functions

There are a number of functions named WithDefault{Type}() which accept the key of an environment variable and a default value. The function checks to see if the environs contains the key and, if not, returns the default value. If the environs does contain the key, then the value of the environment variable with that key is transformed from a string to the {Type} mentioned in the function name.

The functions and their signatures are as follows:

• WithDefault(key string, def string) string: If key isn't found in the environ, returns def

• WithDefaultInt(key string, def int) int: If key isn't found in the environ, returns def. If key is found, converts the environment variable value to an int. If the conversion fails, returns def.

• WithDefaultBool(key string, def bool) bool: If key isn't found in the environ, returns def. If key is found, converts the environment variable value to an bool. If the conversion fails, returns def.

package main

import (
    "fmt"
    "os"

    "github.com/jaypipes/envutil"
)

func main() {
    fmt.Println("Testing envutil...")
    val, ok := os.LookupEnv("SOME_RANDOM_ENV_KEY")
    if !ok {
        fmt.Println(" SOME_RANDOM_ENV_KEY does not exist in environs.")
    } else {
        fmt.Printf(" SOME_RANDOM_ENV_KEY exists in environs with value %s\n", val)
    }
    strval := envutil.WithDefault("SOME_RANDOM_ENV_KEY", "my default str")
    fmt.Printf(" WithDefault(\"SOME_RANDOM_ENV_KEY\", \"my default str\") returned '%s'\n", strval)
    intval := envutil.WithDefaultInt("SOME_RANDOM_ENV_KEY", 42)
    fmt.Printf(" WithDefaultInt(\"SOME_RANDOM_ENV_KEY\", 42) returned %d\n", intval)

    fmt.Println(" Setting SOME_RANDOM_ENV_KEY to 'random str'.")
    os.Setenv("SOME_RANDOM_ENV_KEY", "random str")
    defer os.Unsetenv("SOME_RANDOM_ENV_KEY")
    intval = envutil.WithDefaultInt("SOME_RANDOM_ENV_KEY", 42)
    fmt.Printf(" WithDefaultInt(\"SOME_RANDOM_ENV_KEY\", 42) returned %d\n", intval)

    fmt.Println(" Setting SOME_RANDOM_ENV_KEY to '12'.")
    os.Setenv("SOME_RANDOM_ENV_KEY", "12")
    intval = envutil.WithDefaultInt("SOME_RANDOM_ENV_KEY", 42)
    fmt.Printf(" WithDefaultInt(\"SOME_RANDOM_ENV_KEY\", 42) returned %d\n", intval)

    fmt.Println(" Setting SOME_RANDOM_ENV_KEY to 'falsy'.")
    os.Setenv("SOME_RANDOM_ENV_KEY", "falsy")
    boolval := envutil.WithDefaultBool("SOME_RANDOM_ENV_KEY", true)
    fmt.Printf(" WithDefaultBool(\"SOME_RANDOM_ENV_KEY\", true) returned %v\n", boolval)

    fmt.Println(" Setting SOME_RANDOM_ENV_KEY to 'false'.")
    os.Setenv("SOME_RANDOM_ENV_KEY", "false")
    boolval = envutil.WithDefaultBool("SOME_RANDOM_ENV_KEY", true)
    fmt.Printf(" WithDefaultBool(\"SOME_RANDOM_ENV_KEY\", true) returned %v\n", boolval)
}

Developers

Contributions to envutil are welcomed! Fork the repo on GitHub and submit a pull request with your proposed changes. Or, feel free to log an issue for a feature request or bug report.

Documentation

Index

• func WithDefault(key string, def string) string
• func WithDefaultBool(key string, def bool) bool
• func WithDefaultInt(key string, def int) int

Functions

func WithDefault

func WithDefault(key string, def string) string

Returns the string value of the supplied environ variable or, if not present, the supplied default value

func WithDefaultBool

func WithDefaultBool(key string, def bool) bool

Returns the boolvalue of the supplied environ variable or, if not present, the supplied default value. If the conversion fails, returns the default

func WithDefaultInt

func WithDefaultInt(key string, def int) int

Returns the int value of the supplied environ variable or, if not present, the supplied default value. If the int conversion fails, returns the default