MetaSetup

A package for configuring settings and initializing objects.

Summary

With metasetup, there are no configuration files, just python modules which import and modify settings. This means, that these modules can be used as a "meta" layer on top of normal configuration files, or to programatically configure the settings themselves. To access the settings for a particular module, one need only import it with metasetup as a prefix (e.g. from metasetup.my_package import my_module) and use its attributes.

Installation and Testing

Install metasetup using pip:

pip install metasetup

Run the tests with pytest:

py.test metasetup

For a developer's installation:

1. clone this github repository
2. cd into the parent directory
3. run $ pip install -e .

Basic Usage

For demonstration purposes, we can create a contrived scenario in which the python module configuring settings and the one being configured are the same. Consider the python file which is run by python main.py and has the following contents:

# Import the settings we wish to configure

from metasetup.__main__ import MyClass as MyClassSettings

# and modify the settings as we please

MyClassSettings.x = 1
print(MyClassSettings)

# We then define the Configurable class we want to initialize

from metasetup import Configurable

class MyClass(Configurable):
    """The class whose instances we are about to configure"""
    pass

# Finally, we can create an instance of our class and configure it

mc = MyClass()
mc.configure()
print(mc.x)

# Vualá! The instances of our class can be configured.

Under The Hood

In order to import settings, a SettingsImporter is appended to Python's meta path. Every time a name not defined in metasetup/__init__.py is requested, the importer creates a SettingsModule. The attributes of these modules contain Settings which can be modified, and used to initialize Configurable instances. All Settings are stored globally, and accessible via metapath.import_settings().