Python-dotenv reads key-value pairs from a .env file and can set them as environment
variables. It helps in the development of applications following the
12-factor principles.
- Getting Started
- Other Use Cases
- Command-line Interface
- File format
- Related Projects
- Acknowledgements
pip install python-dotenvIf your application takes its configuration from environment variables, like a 12-factor application, launching it in development is not very practical because you have to set those environment variables yourself.
To help you with that, you can add Python-dotenv to your application to make it load the
configuration from a .env file when it is present (e.g. in development) while remaining
configurable via the environment:
from dotenv import load_dotenv
load_dotenv() # take environment variables from .env.
# Code of your application, which uses environment variables (e.g. from `os.environ` or
# `os.getenv`) as if they came from the actual environment.By default, load_dotenv doesn't override existing environment variables.
To configure the development environment, add a .env in the root directory of your
project:
.
├── .env
└── foo.py
The syntax of .env files supported by python-dotenv is similar to that of Bash:
# Development settings
DOMAIN=example.org
ADMIN_EMAIL=admin@${DOMAIN}
ROOT_URL=${DOMAIN}/appIf you use variables in values, ensure they are surrounded with { and }, like
${DOMAIN}, as bare variables such as $DOMAIN are not expanded.
You will probably want to add .env to your .gitignore, especially if it contains
secrets like a password.
See the section "File format" below for more information about what you can write in a
.env file.
The function dotenv_values works more or less the same way as load_dotenv, except it
doesn't touch the environment, it just returns a dict with the values parsed from the
.env file.
from dotenv import dotenv_values
config = dotenv_values(".env") # config = {"USER": "foo", "EMAIL": "[email protected]"}This notably enables advanced configuration management:
import os
from dotenv import dotenv_values
config = {
**dotenv_values(".env.shared"), # load shared development variables
**dotenv_values(".env.secret"), # load sensitive variables
**os.environ, # override loaded values with environment variables
}load_dotenv and dotenv_values accept streams via their stream
argument. It is thus possible to load the variables from sources other than the
filesystem (e.g. the network).
from io import StringIO
from dotenv import load_dotenv
config = StringIO("USER=foo\n[email protected]")
load_dotenv(stream=config)You can use dotenv in IPython. By default, it will use find_dotenv to search for a
.env file:
%load_ext dotenv
%dotenvYou can also specify a path:
%dotenv relative/or/absolute/path/to/.envOptional flags:
-oto override existing variables.-vfor increased verbosity.
A CLI interface dotenv is also included, which helps you manipulate the .env file
without manually opening it.
$ pip install "python-dotenv[cli]"
$ dotenv set USER foo
$ dotenv set EMAIL [email protected]
$ dotenv list
USER=foo
[email protected]
$ dotenv list --format=json
{
"USER": "foo",
"EMAIL": "[email protected]"
}
$ dotenv run -- python foo.pyRun dotenv --help for more information about the options and subcommands.
The format is not formally specified and still improves over time. That being said,
.env files should mostly look like Bash files.
Keys can be unquoted or single-quoted. Values can be unquoted, single- or double-quoted.
Spaces before and after keys, equal signs, and values are ignored. Values can be followed
by a comment. Lines can start with the export directive, which does not affect their
interpretation.
Allowed escape sequences:
- in single-quoted values:
\\,\' - in double-quoted values:
\\,\',\",\a,\b,\f,\n,\r,\t,\v
It is possible for single- or double-quoted values to span multiple lines. The following examples are equivalent:
FOO="first line
second line"FOO="first line\nsecond line"A variable can have no value:
FOOIt results in dotenv_values associating that variable name with the value None (e.g.
{"FOO": None}. load_dotenv, on the other hand, simply ignores such variables.
This shouldn't be confused with FOO=, in which case the variable is associated with the
empty string.
Python-dotenv can interpolate variables using POSIX variable expansion.
With load_dotenv(override=True) or dotenv_values(), the value of a variable is the
first of the values defined in the following list:
- Value of that variable in the
.envfile. - Value of that variable in the environment.
- Default value, if provided.
- Empty string.
With load_dotenv(override=False), the value of a variable is the first of the values
defined in the following list:
- Value of that variable in the environment.
- Value of that variable in the
.envfile. - Default value, if provided.
- Empty string.
- Honcho - For managing Procfile-based applications.
- django-dotenv
- django-environ
- django-environ-2
- django-configuration
- dump-env
- environs
- dynaconf
- parse_it
- python-decouple
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.
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