environconfig 1.2.0

Application configuration from environment variables made easy

Application configuration from environment variables made easy

from environconfig import EnvironConfig
from environconfig import StringVar, IntVar
from environconfig import VarUnsetError

class AppConfig(EnvironConfig):
    __varprefix__ = 'MYAPP_'

    DB_NAME = StringVar(default='mydatabase')
    DB_HOSTNAME = StringVar(default='localhost')
    DB_PORT = IntVar(default=3306)
    DB_USERNAME = StringVar()
    DB_PASSWORD = StringVar()

    @CustomVar
    def DB_CONFIG(env):
        return {"hostname": env.DB_HOSTNAME,
                "port": env.DB_PORT,
                "user": env.DB_USERNAME,
                "password": env.DB_PASSWORD,
                "database": env.DB_NAME,
                "encoding": "utf-8"}

# Any environment variable defined will be retrieved and casted to
# the python value.
os.environ['MYAPP_DB_NAME'] = 'mydbname'
assert AppConfig.DB_NAME == 'mydbname'

try:
    user = AppConfig.DB_USERNAME
except VarUnsetError:
    # If the environment variable is not set and neither the default
    # value, this exception will be raised when the attribute is
    # accessed.
    pass

# Of course if you provide a default it will be available as a
# fallback.
assert AppConfig.DB_HOSTNAME == 'localhost'

os.environ['MYAPP_DB_PORT'] = 'this is not a valid integer'
try:
    port = AppConfig.DB_PORT
except VarTypeCastError:
    # Verification is made in access time.
    pass

# But you can verify the whole config
AppConfig.verify()  # Return `True` if all attributes have a value
                    # (or a default)

# Or a specific value
AppConfig.verify('DB_PORT')  # Return `True` if a value or a default is
                             # provided for DB_PORT.