In Django, how do I access request variable when validating password?

In Django I need to create a custom password validator which needs to read from the DB to fetch password policy configuration. To do this I need the client ID which is usually embedded in the request variable but in this case, request it is not available. Is there an alternative method to achieve this?

class MinimumLengthValidator:
    """
    Validate whether the password is of a minimum length.
    """
    def __init__(self, min_length=8):
        self.min_length = min_length
        #get minimum length from client config here, typically request.client.config.password_min_length e.g. value is 10

Short answer: You'll find everything here: Integrating validation

Long answer: <br>
I think the most common way is having a custom User model anyways. Meaning having your "own" User model which is subclassed from AbstractUser. There you can overwrite fields, add fields and methods. Fine. Then it totally makes sense to create a User via a ModelForm off that User model. Therefore, starting from your view, you could pass the client ID to the __init__() method of mentioned ModelForm and "pass it down the chain" as @ybl suggested.

But it seems like your project is running entirely on django.contrib.auth with no modification at all to the User model. Hence you are right at saying that above solution is "a lot" just for adding one validator. (Most likely though you are going to add a custom user model anyways in the future (more info), so consider that option).

Write your custom validator:

class CustomValidator:
    def __init__(self, client_id, pw_config):
        self.client_id = client_id
        self.pw_config = pw_config

    def validate(self, user=None):
        if self.client_id != xx and self.pw_config != xx:
            raise ValidationError(
                "pw not valid", 
                code='clientID_not_pwConfig',
                params={'pw_config': self.pw_config, 'client_id': self.client_id},
            )
        # in case pw is valid return None


    def get_help_text(self):
        return _(
            f"Your {self.client_id} does not match pw_config"
        )

Then in your view (resources linked as "short answer" above):

from django.contrib.auth.password_validation import get_password_validators, validate_password


def your_view(request):
    client_id = get_client_id()
    pw_config = get_pw_config()
    standard_validators = get_password_validators(settings.AUTH_PASSWORD_VALIDATORS)
    custom_validator = CustomValidator(client_id, pw_config)
    all_validators = standard_validators + [custom_validator]
    
    if validate_password(
        password,  # replace to your needs
        user=None,  # replace to your needs
        password_validators=all_validators
    ) is not None:
        # your pw is valid
    else:
        # your pw is not valid