        _______ .__   __. ____    ____
       |   ____||  \ |  | \   \  /   /
       |  |__   |   \|  |  \   \/   /
       |   __|  |  . `  |   \      /
    __ |  |____ |  |\   |    \    /
   (__)|_______||__| \__|     \__/

python-dotenv |

Reads the key-value pair from .env file and adds them to environment variable. It is great for managing app settings during development and in production using 12-factor principles.

Do one thing, do it well!

Usages

The easiest and most common usage consists on calling load_dotenv when the application starts, which will load environment variables from a file named .env in the current directory or any of its parents or from the path specificied; after that, you can just call the environment-related method you need as provided by os.getenv.

.env looks like this:

# a comment that will be ignored.
REDIS_ADDRESS=localhost:6379
MEANING_OF_LIFE=42
MULTILINE_VAR="hello\nworld"

You can optionally prefix each line with the word export, which is totally ignored by this library, but might allow you to source the file in bash.

export S3_BUCKET=YOURS3BUCKET
export SECRET_KEY=YOURSECRETKEYGOESHERE

Python-dotenv can interpolate variables using POSIX variable expansion.

The value of a variable is the first of the values defined in the following list:

Value of that variable in the .env file.
Value of that variable in the environment.
Default value, if provided.
Empty string.

Ensure that variables are surrounded with {} like ${HOME} as bare variables such as $HOME are not expanded.

CONFIG_PATH=${HOME}/.config/foo
DOMAIN=example.org
EMAIL=admin@${DOMAIN}
DEBUG=${DEBUG:-false}

Getting started

Install the latest version with:

pip install -U python-dotenv

Assuming you have created the .env file along-side your settings module.

.
├── .env
└── settings.py

Add the following code to your settings.py:

# settings.py
from dotenv import load_dotenv
load_dotenv()

# OR, the same with increased verbosity
load_dotenv(verbose=True)

# OR, explicitly providing path to '.env'
from pathlib import Path  # Python 3.6+ only
env_path = Path('.') / '.env'
load_dotenv(dotenv_path=env_path)

At this point, parsed key/value from the .env file is now present as system environment variable and they can be conveniently accessed via os.getenv():

# settings.py
import os
SECRET_KEY = os.getenv("EMAIL")
DATABASE_PASSWORD = os.getenv("DATABASE_PASSWORD")

load_dotenv does not override existing System environment variables. To override, pass override=True to load_dotenv().

load_dotenv also accepts encoding parameter to open the .env file. The default encoding is platform dependent (whatever locale.getpreferredencoding() returns), but any encoding supported by Python can be used. See the codecs module for the list of supported encodings.

You can use find_dotenv() method that will try to find a .env file by (a) guessing where to start using __file__ or the working directory -- allowing this to work in non-file contexts such as IPython notebooks and the REPL, and then (b) walking up the directory tree looking for the specified file -- called .env by default.

from dotenv import load_dotenv, find_dotenv
load_dotenv(find_dotenv())

In-memory filelikes

It is possible to not rely on the filesystem to parse filelikes from other sources (e.g. from a network storage). load_dotenv and dotenv_values accepts a filelike stream. Just be sure to rewind it before passing.

>>> from io import StringIO     # Python2: from StringIO import StringIO
>>> from dotenv import dotenv_values
>>> filelike = StringIO('SPAM=EGGS\n')
>>> filelike.seek(0)
>>> parsed = dotenv_values(stream=filelike)
>>> parsed['SPAM']
'EGGS'

The returned value is dictionary with key-value pairs.

dotenv_values could be useful if you need to consume the envfile but not apply it directly into the system environment.

Django

If you are using Django, you should add the above loader script at the top of wsgi.py and manage.py.

IPython Support

You can use dotenv with IPython. You can either let the dotenv search for .env with %dotenv or provide the path to the .env file explicitly; see below for usages.

%load_ext dotenv

# Use find_dotenv to locate the file
%dotenv

# Specify a particular file
%dotenv relative/or/absolute/path/to/.env

# Use '-o' to indicate override of existing variables
%dotenv -o

# Use '-v' to turn verbose mode on
%dotenv -v

Command-line Interface

For command-line support, use the CLI option during installation:

pip install -U "python-dotenv[cli]"

A CLI interface dotenv is also included, which helps you manipulate the .env file without manually opening it. The same CLI installed on remote machine combined with fabric (discussed later) will enable you to update your settings on a remote server; handy, isn't it!

Usage: dotenv [OPTIONS] COMMAND [ARGS]...

  This script is used to set, get or unset values from a .env file.

Options:
  -f, --file PATH                 Location of the .env file, defaults to .env
                                  file in current working directory.

  -q, --quote [always|never|auto]
                                  Whether to quote or not the variable values.
                                  Default mode is always. This does not affect
                                  parsing.

  -e, --export BOOLEAN
                                  Whether to write the dot file as an
                                  executable bash script.

  --version                       Show the version and exit.
  --help                          Show this message and exit.

Commands:
  get    Retrieve the value for the given key.
  list   Display all the stored key/value.
  run    Run command with environment variables present.
  set    Store the given key/value.
  unset  Removes the given key.

Setting config on Remote Servers

We make use of excellent Fabric to accomplish this. Add a config task to your local fabfile; dotenv_path is the location of the absolute path of .env file on the remote server.

# fabfile.py

import dotenv
from fabric.api import task, run, env

# absolute path to the location of .env on remote server.
env.dotenv_path = '/opt/myapp/.env'

@task
def config(action=None, key=None, value=None):
    '''Manage project configuration via .env

    e.g: fab config:set,<key>,<value>
         fab config:get,<key>
         fab config:unset,<key>
         fab config:list
    '''
    run('touch %(dotenv_path)s' % env)
    command = dotenv.get_cli_string(env.dotenv_path, action, key, value)
    run(command)

Usage is designed to mirror the Heroku config API very closely.

Get all your remote config info with fab config:

$ fab config
foo="bar"

Set remote config variables with fab config:set,<key>,<value>:

$ fab config:set,hello,world

Get a single remote config variables with fab config:get,<key>:

$ fab config:get,hello

Delete a remote config variables with fab config:unset,<key>:

$ fab config:unset,hello

Thanks entirely to fabric and not one bit to this project, you can chain commands like so: fab config:set,<key1>,<value1> config:set,<key2>,<value2>

$ fab config:set,hello,world config:set,foo,bar config:set,fizz=buzz

Related Projects

Honcho - For managing Procfile-based applications.
django-dotenv
django-environ
django-configuration
dump-env
environs
dynaconf

Acknowledgements

This project is currently maintained by Saurabh Kumar and Bertrand Bonnefoy-Claudet and would not have been possible without the support of these awesome people.

peymanslh/python-dotenv