dotenv.nim

dotenv implementation for Nim. Loads environment variables from .env

Storing configuration in the environment is one of the tenets of a twelve-factor app. Anything that is likely to change between deployment environments–such as resource handles for databases or credentials for external services–should be extracted from the code into environment variables.

Installation

dotenv can be installed using Nimble:

nimble install dotenv

Or add the following to your .nimble file:

# Dependencies

requires "dotenv >= 2.0.0"

Usage

Create a .env file

Create a .env file in the root of your project (or anywhere else - just be sure to specify the path when loading).

DB_HOST=localhost
DB_USER=root
DB_PASS=""
DB_NAME=test

Variables values are always strings, and can be either wrapped in quotes or left without.

Multiline strings can also be used using the """ syntax:

SOME_LONG_STRING="""This string is very long.

It will span multiple lines.
"""

You can also add comments, using the # symbol:

# Comments can fill a whole line
DB_NAME=test # Or they can follow an assignment

Variable values can reference other variables - either from the same .env file, or from the existing environment variables:

CONFIG_DIR=${HOME}/.config
CONFIG_FILE=${CONFIG_DIR}/config.json

• Variables are referenced either using ${VARIABLE} or as simply $VARIABLE.
• Variables do not need to be defined before usage.
• Unknown variables are replaced with empty strings.

Loading the .env file

You can load the .env file from the current working directory as follows:

import dotenv

load()

Or, you can specify the path to the directory and/or file:

import dotenv, std/os

load("/some/directory/path", "custom_file_name.env")

# You can now access the variables using os.getEnv()

By default, dotenv does not overwrite existing environment variables, though this can be done using overload rather than load:

import dotenv, std/os

overload()

# You can now access the variables using os.getEnv()

Loading from a string

You can also load environment variables directly from a string using std/streams:

import dotenv, std/[streams, os]

load(newStringStream("""hello = world
foo = bar
"""))

assert getEnv("foo") == "bar"