invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)

Squashed commits:
[62dd3f1] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[4269e3b] disble protected access in pylint

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[eb32c9a] fixed the python quality issue of accessing protected fields
fixed the failing tests

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[4269e3b] disble protected access in pylint

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+2 squashed commits)
Squashed commits:
[4bfe22b] remove the delete case because there is none in current scenario
[802c259] moved the test case to user profile properties file

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[4269e3b] disble protected access in pylint

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[eb32c9a] fixed the python quality issue of accessing protected fields
fixed the failing tests

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[4269e3b] disble protected access in pylint

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[98d2415] added better log info message

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[62dd3f1] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[4269e3b] disble protected access in pylint

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[eb32c9a] fixed the python quality issue of accessing protected fields
fixed the failing tests

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[4269e3b] disble protected access in pylint

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+2 squashed commits)
Squashed commits:
[4bfe22b] remove the delete case because there is none in current scenario
[802c259] moved the test case to user profile properties file

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[4269e3b] disble protected access in pylint

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[eb32c9a] fixed the python quality issue of accessing protected fields
fixed the failing tests

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[4269e3b] disble protected access in pylint

invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[0246b1b] invalidate UserProfile.country cache when UserProfile is updated (+1 squashed commit)
Squashed commits:
[7c4fecf] invalidate UserProfile.country cache when UserProfile is updated

common/djangoapps/student/models.py

@@ -213,6 +213,8 @@ class UserProfile(models.Model):
     Some of the fields are legacy ones that were captured during the initial
     MITx fall prototype.
     """
+    # cache key format e.g user.<user_id>.profile.country = 'SG'
+    PROFILE_COUNTRY_CACHE_KEY = u"user.{user_id}.profile.country"
 
     class Meta(object):  # pylint: disable=missing-docstring
         db_table = "auth_userprofile"
@@ -368,6 +370,29 @@ class UserProfile(models.Model):
         """ Get the human readable value from an enumerable list of key-value pairs. """
         return dict(enumerables)[enum_value]
 
+    @classmethod
+    def country_cache_key_name(cls, user_id):
+        """Return cache key name to be used to cache current country.
+        Args:
+            user_id(int): Id of user.
+
+        Returns:
+            Unicode cache key
+        """
+        return cls.PROFILE_COUNTRY_CACHE_KEY.format(user_id=user_id)
+
+
+@receiver(models.signals.post_save, sender=UserProfile)
+def invalidate_user_profile_country_cache(sender, instance, **kwargs):  # pylint:   disable=unused-argument, invalid-name
+    """Invalidate the cache of country in UserProfile model. """
+
+    changed_fields = getattr(instance, '_changed_fields', {})
+
+    if 'country' in changed_fields:
+        cache_key = UserProfile.country_cache_key_name(instance.user_id)
+        cache.delete(cache_key)
+        log.info("Country changed in UserProfile for %s, cache deleted", instance.user_id)
+
 
 @receiver(pre_save, sender=UserProfile)
 def user_profile_pre_save_callback(sender, **kwargs):

common/djangoapps/student/tests/test_user_profile_properties.py

@@ -6,6 +6,7 @@ from django.test import TestCase
 
 from student.models import UserProfile
 from student.tests.factories import UserFactory
+from django.core.cache import cache
 
 
 @ddt.ddt
@@ -77,3 +78,22 @@ class UserProfilePropertiesTest(TestCase):
         self._set_gender(None)
 
         self.assertIsNone(self.profile.gender_display)
+
+    def test_invalidate_cache_user_profile_country_updated(self):
+
+        country = 'us'
+        self.profile.country = country
+        self.profile.save()
+
+        cache_key = UserProfile.country_cache_key_name(self.user.id)
+        self.assertIsNone(cache.get(cache_key))
+
+        cache.set(cache_key, self.profile.country)
+        self.assertEqual(cache.get(cache_key), country)
+
+        country = 'bd'
+        self.profile.country = country
+        self.profile.save()
+
+        self.assertNotEqual(cache.get(cache_key), country)
+        self.assertIsNone(cache.get(cache_key))