Values not working in DATABASES dictionary and values.Value returning Value instance type instead of a str

[eduardo-boutiquenumerique]

I'm using the lastest pypi version 2.5.

I'm trying to configure my db with separate variables in .env.
I have the following:
DJANGO_DB_NAME=dbname
DJANGO_DB_USER=dbuser
DJANGO_DB_PASSWORD=dbpassword

First of all, if I define them in the DATABASES dictionary they are all None

DATABASES = {
    'default': {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": values.Value(environ_name="DB_NAME"),
        "USER": values.Value(environ_name="DB_USER"),
        "PASSWORD": values.SecretValue(environ_name="DB_PASSWORD"),
        "HOST": "",
        "PORT": "",
    }
}

I get an error saying "ValueError: Value 'DB_PASSWORD' is required to be set as the environment variable 'DJANGO_DB_PASSWORD'" although it's well defined. I have debuging to see if the .env file is loaded and at the end of the "load_dotenv" method is configurations/base.py all the variables are in os.environ.

Also, when I checked the values of NAME and USER, they are "None" instead of correct values.

Second, if I move the values outside of the dictionary as follows:

DB_NAME = values.Value()
DB_USER = values.Value()
DB_PASSWORD = values.SecretValue()

DATABASES = {
    'default': {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": DB_NAME,
        "USER": DB_USER,
        "PASSWORD": DB_PASSWORD,
        "HOST": values.Value(environ_name="DB_HOST", environ_prefix=None),
        "PORT": values.Value(default="5432", environ_name="DB_PORT", environ_prefix=None),
        "OPTIONS": values.DictValue(environ_name="DB_OPTIONS", environ_prefix=None),
    }
}

I get an error in "File "django/db/backends/postgresql/base.py", line 200, in get_connection_params" saying
"TypeError: object of type 'Value' has no len()"
The line in question is "if len(settings_dict["NAME"] or "") > self.ops.max_name_length():"

Again, debugging it, I can verify that type(settings_dict["NAME"]) is "configurations.Value"
The DB_USER and DB_PASSWORD don't seem to cause any issue.

For some unexplained reason, converting it to string as str(DB_NAME) does't work, since it gives me the string "none" as "NAME" in the dictionary.

Third, I tried using the DatabaseURLValue and it works, but when I try to add the "OPTIONS" key to the db dict in order to add the schema info, I get an error saying "*** TypeError: 'DatabaseURLValue' object is not subscriptable"

Here is the code :
DATABASES = values.DatabaseURLValue()
DATABASES["default"]["OPTIONS"] = values.DictValue(environ_name="DB_OPTIONS", environ_prefix=None)

Can you explain all the 3 issues I'm having ?

[eduardo-boutiquenumerique]

BTW, I'm using successfully the 1st approach, where I define the variables in the dictionary itself, in a project in python 2.7, django 1.11.29 and django-configraitons 1.0

EDIT: I actually found a difference that in my project where I'm using the 1st approach. I'm not defining an attribute DATABASES, but a property as in

@property
def DATABASES(self):
    return {"default": ...}

Why is it ?