Feature idea: optional value

[kazet]

so that e.g. I could write MAX_RETRIES = decouple.config("MAX_RETRIES", cast=Optional(int), default=None), which will be None if MAX_RETRIES is not set and int value if it is.

Currently such configuration produces:

TypeError: int() argument must be a string, a bytes-like object or a real number, not 'NoneType'

[lucasrcezimbra]

You can create a custom cast function.

MAX_RETRIES = decouple.config("MAX_RETRIES", cast=lambda v: int(v) if v else None, default=None)

[henriquebastos]

You can also achieve this with something like:

class Optional:
    def __init__(self, type):
        self.type = type

    def __call__(self, value):
        try:
            return self.type(value)
        except:
            return None

MAX_RETRIES = decouple.config("MAX_RETRIES", cast=Optional(int), default=None)