Add new XBlock runtime service 'MilestonesService'

milestones/services.py

+"""
+A wrapper class around requested methods exposed in api.py
+"""
+
+import types
+
+from milestones import api as milestones_api
+
+
+class MilestonesService(object):  # pylint: disable=too-few-public-methods
+    """
+    An xBlock service for xBlocks to talk to the Milestones subsystem.
+
+    NOTE: This is a Singleton class. We should only have one instance of it!
+    """
+
+    _instance = None
+
+    REQUESTED_FUNCTIONS = [
+        'get_course_content_milestones',
+    ]
+
+    def __new__(cls, *args, **kwargs):
+        """
+        This is the class factory to make sure this is a Singleton
+        """
+        if not cls._instance:
+            cls._instance = super(MilestonesService, cls).__new__(cls, *args, **kwargs)
+        return cls._instance
+
+    def __init__(self):
+        """
+        Class initializer, which just inspects the libraries and exposes the same functions
+        listed in REQUESTED_FUNCTIONS
+        """
+        self._bind_to_requested_functions()
+
+    def _bind_to_requested_functions(self):
+        """
+        bind module functions. Since we use underscores to mean private methods, let's exclude those.
+        """
+        for attr_name in self.REQUESTED_FUNCTIONS:
+            attr = getattr(milestones_api, attr_name, None)
+            if isinstance(attr, types.FunctionType) and not attr_name.startswith('_'):
+                if not hasattr(self, attr_name):
+                    setattr(self, attr_name, attr)

milestones/tests/test_services.py

+"""
+Test for the xBlock service
+"""
+
+import unittest
+import types
+
+from milestones.services import MilestonesService
+from milestones import api as milestones_api
+
+
+class TestMilestonesService(unittest.TestCase):  # pylint: disable=too-many-public-methods
+    """
+    Tests for MilestonesService
+    """
+    def test_basic(self):
+        """
+        See if the MilestonesService exposes the expected methods
+        """
+
+        service = MilestonesService()
+
+        for attr_name in dir(milestones_api):
+            attr = getattr(milestones_api, attr_name, None)
+            if isinstance(attr, types.FunctionType) and not attr_name.startswith('_'):
+                if attr_name in MilestonesService.REQUESTED_FUNCTIONS:
+                    self.assertTrue(hasattr(service, attr_name))
+                else:
+                    self.assertFalse(hasattr(service, attr_name))
+
+    def test_singleton(self):
+        """
+        Test to make sure the MilestonesService is a singleton.
+        """
+        service1 = MilestonesService()
+        service2 = MilestonesService()
+        self.assertIs(service1, service2)

setup.py

@@ -4,7 +4,7 @@ from setuptools import setup, find_packages
 
 setup(
     name='edx-milestones',
-    version='0.1.8',
+    version='0.1.9',
     description='Significant events module for Open edX',
     long_description=open('README.md').read(),
     author='edX',