To load from your local environment, use the load function to return an EnvDict instance.:

>>> from sysenv import load
>>> env = load()

By default it loads from the system environment, but you can also include values from a .env or similar file.:

>>> from sysenv import load
>>> env = load('.env')


The load function returns a new EnvDict instance and also updates the system environment with values in the provided file so that later calles to os.environ will pick up on these new variables or values.

The EnvDict instance can be accessed like a normal Python dictionary.:

>>> env['DEBUG']
>>> env.get('DEBUG', False)

Of course your environment variables are strings, so you’ll want to cast the return value to a boolean.:

>>> env.get('DEBUG', False, cast=bool)

Type schemas

Alternatively you can define a schema when you initialize your EnvDict. For example, to ensure that the value for DEBUG is rendered internally as a boolean value and CACHE_COUNT is rendred as an integer:

>>> env = EnvDict(schema={'DEBUG': bool, 'CACHE_COUNT': int})
>>> env.get('DEBUG')
>>> env['DEBUG']
>>> env = load(schema={'DEBUG': bool, 'CACHE_COUNT': int})
>>> env.get('CACHE_COUNT')
>>> env['CACHE_COUNT']

The schema should be provided as a dictionary of key names with the cast identifier given as the value in the schema.

Type casting

By default an EnvDict instance can cast to these types:

  • str (default)
  • bool
  • int
  • float
  • Decimal
  • list
  • dict

Each type can be cast using a built-in dictionary that uses the type (by type object or name) as the key and the type constructor or other passable function as the value.

All built-in types are cast using the type as the casting dictionary key, e.g.:

env.get('MY_VAR', cast=list)

Non-built in types should be referenced by lowercased string name, e.g.:

env.get('MY_VAR', cast='decimal')

bool conversion

Booleans are cast by comparing the lowercased input against a tuple of “true” values:

  • true
  • on
  • yes
  • 1

True is returned if the filtered input is in the tuple, otherwise False.

list converstion

The list conversion produces a list of strings based on the input, e.g. it will turn:



>>> env.get('MYVAR', cast=list)
['1', '2', '3', '4']

dictionary conversion

The dictionary conversion produces a dictionary of string keys and values based on the input, e.g. it will turn:



>>> env.get('MYVAR', cast=dict)
{'a': '1', 'b': '2', 'c': '3', 'd': '4'}

Extending type casting

You can replace or add type casting methods. Simply pass a dictionary using the casts keyword when creating an EnvDict instance.:

>>> MY_TRUE_VALUES = ('true', 'for sure')
>>> env = EnvDict({'DEBUG': 'For SURE'}, casts={bool: lambda x: x.lower in MY_TRUE_VALUES})
>>> env.get('DEBUG', cast=bool)

The same dictionary can be based when loading the environment.:

>>> MY_TRUE_VALUES = ('true', 'for sure')
>>> env = load(casts={bool: lambda x: x.lower in MY_TRUE_VALUES})
>>> env.get('DEBUG', cast=bool)

Using with Django

To use SysEnv in your Django project add it to the top of your file and pull in setting values from the env variable (or whatever you call it).:

from sysenv import load
env = load('.env')
DEBUG = env.get('DEBUG', False, cast=bool)

Note that SysEnv does not offer functionality for configuring database or working with file paths. There are already libraries that do those things.

You can configure your database(s) using DJ-Database-URL.:

DATABASES = {'default': dj_database_url.config(default='postgres://localhost')}

Got search? You can use DJ-Search-URL.:

HAYSTACK_CONNECTIONS = {"default": dj_search_url.conf("elasticsearch://..")}

If you want to make working with file paths simpler you should take a look at

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