MDIA vDOTENV

A small library for reading and loading environment variables.

IMPORTANT: Make sure any environment files with sensitive information is added to your .gitignore. Never check-in these files

Quick start

Create a .env file in your project root with the following contents

PULUMI_ACCESS_TOKEN=topsecret
PULUMI_BACKEND_URL=s3://your-pulumi-state-bucket

In your application import the library and call vdotenv.load_env_default() to load the .env file.

module main

import os
import mdia.vdotenv

fn main() {
	vdotenv.load_env_default() or { panic(err) }

	println(os.getenv('PULUMI_ACCESS_TOKEN'))
	println(os.getenv('PULUMI_BACKEND_URL'))
}

Running the above code will print the following in your terminal

topsecret
s3://your-pulumi-state-bucket

Defining Environment Variables

This library tries to be as flexible as sh when handling environment variable declarations. Therefore, you can define your environment variables as you would in your shellscripts.

Below are some examples of supported environment variable declarations:

• export PULUMI_ACCESS_TOKEN=topsecret
• readonly PULUMI_BACKEND_URL=s3://your-pulumi-state-bucket
• readonly export METAL_AUTH_TOKEN='top-secret'
• METAL_PROJECT_ID=af7eff2b-2a0f-4a8a-bd1d-4cc0a909d786
• METAL_EXT_ASSET_PATH="${PULUMI_BACKEND_URL}/${METAL_PROJECT_ID}"

Important

Only variables in "double quoted" declaration values will be expanded. Variables found in single quoted or unquoted declaration values will be parsed as is.

Example

M3O_API_CMD='m3o --api-key="${M3O_API_TOKEN}" explore'

will return the literal

m3o --api-key="${M3O_API_TOKEN}" explore

Loading Environment Variables

Environment files can be loaded using vdotenv.load_env_default() and vdotenv.load_env

vdotenv.load_env_default() uses default configurations to load your environment file which must be in the current directory and be name .env

vdotenv.load_env allows custom configurations on how your environment files are loaded.

module main

import os
import mdia.vdotenv

fn main() {
	vdotenv.load_env(
		paths: ['.env', '.winry'],
		strict: false,
		required_keys: ['PULUMI_ACCESS_TOKEN', 'PULUMI_BACKEND_URL']
	) or { panic(err) }

	println(os.getenv('PULUMI_ACCESS_TOKEN'))
	println(os.getenv('PULUMI_BACKEND_URL'))
}

Config Name	Type	Default	Notes
paths	[]string	[]	Optional relative or absolute paths to environment files
override	bool	false	Override existing environment variables
strict	bool	true	Returns an error if a referenced variable is not set
required_keys	[]string	[]	Optional set of required keys. An error will be returned if any required key is not set, whether in strict mode or not.

Accessing Environment Variables

Once loaded you can access the environment variables using os.getenv and os.getenv_opt.

vdotenv.load_env_default() and vdotenv.load_env return a map of all the loaded environment variables. This can be handy as you do not have to keep calling os.getenv* to access your variables.

module main

import os
import mdia.vdotenv

fn main() {
	env := vdotenv.load_env(
		paths: ['.env', '.winry'],
		strict: false,
		required_keys: ['PULUMI_ACCESS_TOKEN', 'PULUMI_BACKEND_URL']
	) or { panic(err) }

	println(env['PULUMI_ACCESS_TOKEN'])
	println(env['PULUMI_BACKEND_URL'])
}

For best results I recommend using this with strict: true and passing required_keys

The library comes with 2 convenience functions vdotenv.env and vdotenv.env_or_default.

• vdotenv.env - Returns an error if the requested variable it not set.
• vdotenv.env_or_default - If the requested variable is not set use the given default.