jaypipes / envutil

Tiny library with some environment variable utility functions

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.