Getting error [password authentication failed for user] while encrypt DB credential in Django

Question

Hi Everyone i am working on django framework my credential store in config.ini file but when i encrypt my db password and run server getting 500 error in log showing password authentication failed for user this will happen when i encrypt db password and store in same config.ini file bt i store new config.ini file it will work but i need to store db password encryption in existing config.ini file please help me out.

settings.py

from cryptography.fernet import Fernet

key = Fernet.generate_key()
with open('key.key', 'wb') as key_file:
    key_file.write(key)


# Define encrypt 
def encrypt(value):
    with open('key.key', 'rb') as key_file:
        key = key_file.read()
    f = Fernet(key)
    return f.encrypt(value.encode()).decode()

#Define decrypt functions
def decrypt(value):
    with open('key.key', 'rb') as key_file:
        key = key_file.read()
    f = Fernet(key)
    return f.decrypt(value.encode()).decode()
    
# Read config file:------------------------------------------------------------
config = RawConfigParser()
config.read(os.path.join(config_path, 'config.ini'))

DB_PASSWORD = config['db_setting']['DB_PASSWORD']

encrypt_db_password=encrypt(DB_PASSWORD)

# update  config.ini file with encrypt_db_password
config.set('db_setting','DB_PASSWORD', encrypt_db_password)
with open('utility\config.ini', 'w') as config_file:
    config.write(config_file)

#decrypt db_password
decrypted_db_password = decrypt(encrypt_db_password)

DATABASES = {
        'default': {
                'ENGINE': 'django.db.backends.postgresql_psycopg2',
                'NAME': 'db',
                'USER': DB_USER,
                'PASSWORD': decrypted_db_password,
                'HOST': DB_HOST,
                'PORT': DB_PORT,
                'CONN_MAX_AGE': MAX_CONNECTION_AGE,
                'OPTIONS': {'options': '-c search_path=' + SCHEMA + ',public'}
        }

try to encrypt decrypt db password i will work when db credential store new config.ini file but i need to store my credential with encyption in existing config.ini file. as per me this line generate issue

1- this will not work

update config.ini file with encrypt_db_password

config.set('db_setting','DB_PASSWORD', encrypt_db_password)
with open('utility\config.ini', 'w') as config_file:
    config.write(config_file)

**2- this will work **

creating config.ini file with encrypt_db_password

config.set('db_setting','DB_PASSWORD', encrypt_db_password)
with open('config.ini', 'w') as config_file:
    config.write(config_file)