Createnv

A simple CLI to create .env files.

Motivation

I use .env file to decouple configuration from application in many projects, and I see that many newcomers might struggle in creating this file.

Thus, I created this package to offer a better user interface for creating configuration files in the format of .env.

Example

Using the sample .env.sample in this repository:

You can now experiment by yourself, or try more advanced .env.sample such as the tests/.env.sample or [Bot Followers's .env.sample]

Install

Createnv requires Python 3.7 or newer:

$ pip install createnv

Usage

To use the default values (reads the sample from .env.sample and write the result into .env):

$ createnv

Options

Option	Default	Description
--target	.env	File to write the result
--source	.env.sample	File to use as a sample
--overwrite and --no-overwrite	--no-overwrite	Whether to ask before overwriting files
--use-default or --no-use-default	--no-use-default	Whether to ask for input on fields that have a default value set
--chars-for-random-string	All ASCII letters, numbers and a few extra characters (!@#$%^&*(-_=+))	Characters used to create random strings

Format of sample files

Createnv reads the sample file and separate lines in blocks, splitting at empty lines. It follows a few rules:

1. The first line is required to be a title
2. The second line might be a description or a variable
3. The remaining lines should be variables

Title

The first line of the block should start with a # character, followed by a space. The title value is the remaining text after the # and space.

Example

# Hell Yeah!

In this case, the title is Hell yeah! (not # Hell yeah!).

Description (optional)

If the second line follows the syntax of a title line, it's text (without the # ) is considered a description and is used to give more information to the user about the variables from this block.

Variables

There are three types of variables:

Regular

Each block might one or more variable lines. The syntax requires a name of variable using only capital letters, numbers, or underscore, followed by an equal sign.

What comes after the equal sign is optional. This text is considered the default value of this variable.

The human description of this variable is also optional. You can create one by placing a comment at the end of the line. That is to say, any text after a sequence of two spaces, followed by the # sign and one extra space, is the human description of that variable.

Example

NAME=

This is a valid variable line. It has a name (NAME), no default value, and no human description. We can add a default value:

NAME=Cuducos

This is still a valid variable line. It has a name(NAME), and a default value (Cuducos). Yet, we can add a human description:

NAME=Cuducos  # What is your name?

Now it's a complete variable with a name (NAME), a default value (Cuducos), and a human description (What is your name?)

Random values

If you want to have a variable with a random value, you can set its default value to <random> and Createnv will take care of it. Optionally you can specify how long this variable should be with :int.

You can use the --chars-for-random-string option to specify which characters to be used in the random value.

Example

SECRET_KEY=<random>
TOKEN=<random:32>

The first line will create a SECRET_VALUE with random characters and random length between 64 and 128 chars.

The second line will create a TOKEN with random value and with exactly 32 characters.

Auto generated

Finally, you can combine existing variables within the same block to create a new variable (without prompting your user to combine them), the syntax is similar to f-strings in Python..

Example

NAME=  # What is your name?
PERIOD=  # Is it morning, afternoon, or evening?
GREETING=Good {PERIOD}, {NAME}!

In this case, Createnv only asks the user for NAME and PERIOD, and creates GREETING automagically.