Configuring using class-based settings

An interesting way of laying out configurations for different deployment modes, such as production, testing, staging, and so on, can be cleanly done using the inheritance pattern of classes. As your project gets bigger, you can have different deployment modes, such as development, staging, production, and so on, where each mode can have several different configuration settings, or some settings that will remain the same. In this recipe, we will learn how to use class-based settings to achieve such a pattern.

How to do it...

We can have a default setting base class, and other classes can inherit that base class and override or add deployment-specific configuration variables to it, as shown in the following example:

class BaseConfig(object): 
    'Base config class' 
    SECRET_KEY = 'A random secret key' 
    DEBUG = True 
    TESTING = False 
    NEW_CONFIG_VARIABLE = 'my value' 
 
class ProductionConfig(BaseConfig): 
    'Production specific config' 
    DEBUG = False 
    SECRET_KEY = open('/path/to/secret/file').read() 
 
class StagingConfig(BaseConfig): 
    'Staging specific config' 
    DEBUG = True 
 
class DevelopmentConfig(BaseConfig): 
    'Development environment specific config' 
    DEBUG = True 
    TESTING = True 
 
    SECRET_KEY = 'Another random secret key' 

The secret key is stored in a separate file because, for security reasons, it should not be a part of your version-control system. This should be kept in the local filesystem on the machine itself, whether it is your personal machine or a server.

How it works...

Now we can use any of the preceding classes while loading the application's configuration via from_object(). Let's say that we save the preceding class-based configuration in a file named configuration.py, as follows:

app.config.from_object('configuration.DevelopmentConfig') 

Overall, this makes the management of configurations for different deployment environments more flexible and easy.