defaultenv

Environment and config file reader for python3. Warrning: slightly magic inside. This module magically read and use environment value both from '.env' file and environment itself.

Since version 0.0.6 .env file will be rereaded on the fly on next env call, so now your environment is always up to date.

$ echo "MY_VAL='test'" > .env
$ python
>>> from defaultenv import env
>>> env('PATH')
'/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin'
>>> env('TEST')
>>> env('MY_VAL')
'test'
>>> import os; os.environ['MY_VAL']
'test'

env method may be used to check the value of variable. If variable is not defined env method will return None. If both environment variable and corresponding .env record is exist then .env have a priority. And yes, you can use os.environ instead of env(), all records from .env will be exported immidiately.

For additional convinience you can use env() with default argument, for example:

>>> from defaultenv import env
>>> env('TEST', 'no test')
'no test'
>>> env('UID')
'1000'
>>> env('UID', int)
1000
>>> env('HOME', pathlib.Path)
PosixPath("/home/bobuk")
>>> env('PATH', lambda x: [pathlib.Path(_) for _ in x.split(':')])
[PosixPath('/usr/local/sbin'), PosixPath('/usr/local/bin'), PosixPath('/usr/sbin'), PosixPath('/usr/bin'),
 PosixPath('/sbin'), PosixPath('/bin')]

If default argument for env() is not empty, and key what you looking for is not exists env() will return you value of default. But if default is callable (like object, lambda or function) then instead value of key from environment will be passed to this callable. My favorite is to send just int because it's the easiest way to convert your default to integer.

Since version 0.0.2 for more convinience two classes (ENV and ENVC) was added. You can use your environment variable name without method calling.

$ python
>>> from defaultenv import ENV
>>> ENV.PATH
'/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin'

ENV usage removing unnesesery typing of perenthesis and quotes. In this example i've save 4 keystrokes for you. But it's not very convinient to type uppercased name everytime. Let's imagine what my pinky finger is killing me.

$ python
>>> from defaultenv import ENVC as env
>>> env.shell
'/usr/local/bin/zsh'
>>> env.home
'/home/bobuk'

As you can see ENVC convert your variable name to uppercase. For both ENVC and ENV there's a method defaults to add default values of callables (as for env above).

>>> from defaultenv import ENVC as env
>>> env.defaults(test = 1, path = lambda x: x.split(':'), pid=int)
>>> env.test
1
>>> env.path
['/usr/local/sbin', '/usr/local/bin', '/usr/sbin', '/usr/bin', '/sbin', '/bin']

What the difference between os.environ.get('PATH', None) and env.path? It's easy to calculate and the result is 21 (which is half of 42).

Since version 0.0.9 you can use even more authomated ENVCD which is ENVC but with predefined defaults. Every path (or colon-separated paths list) will be defaulted to PosixPath, every digital value converted to int.

>>> from defaultenv import ENVCD as env
>>> env.path
[PosixPath('/usr/local/bin'), PosixPath('/usr/local/bin'), PosixPath('/usr/bin'), PosixPath('/bin'), PosixPath('/usr/sbin')]