Can disable rate limiting for enrollment API end-points using model-based configuration.

common/djangoapps/enrollment/views.py

@@ -12,6 +12,7 @@ from rest_framework.views import APIView
 from enrollment import api
 from enrollment.errors import CourseNotFoundError, CourseEnrollmentError, CourseModeNotFoundError
 from util.authentication import SessionAuthenticationAllowInactiveUser
+from util.disable_rate_limit import can_disable_rate_limit
 
 
 class EnrollmentUserThrottle(UserRateThrottle):
@@ -20,6 +21,7 @@ class EnrollmentUserThrottle(UserRateThrottle):
     rate = '50/second'
 
 
+@can_disable_rate_limit
 class EnrollmentView(APIView):
     """
         **Use Cases**
@@ -101,6 +103,7 @@ class EnrollmentView(APIView):
             )
 
 
+@can_disable_rate_limit
 class EnrollmentCourseDetailView(APIView):
     """
         **Use Cases**
@@ -169,6 +172,7 @@ class EnrollmentCourseDetailView(APIView):
             )
 
 
+@can_disable_rate_limit
 class EnrollmentListView(APIView):
     """
         **Use Cases**

common/djangoapps/util/admin.py

@@ -0,0 +1,7 @@
+"""Admin interface for the util app. """
+
+from ratelimitbackend import admin
+from util.models import RateLimitConfiguration
+
+
+admin.site.register(RateLimitConfiguration)

common/djangoapps/util/disable_rate_limit.py

@@ -0,0 +1,86 @@
+"""Utilities for disabling Django Rest Framework rate limiting.
+
+This is useful for performance tests in which we need to generate
+a lot of traffic from a particular IP address.  By default,
+Django Rest Framework uses the IP address to throttle traffic
+for users who are not authenticated.
+
+To disable rate limiting:
+
+1) Decorate the Django Rest Framework APIView with `@can_disable_rate_limit`
+2) In Django's admin interface, set `RateLimitConfiguration.enabled` to False.
+
+Note: You should NEVER disable rate limiting in production.
+
+"""
+from functools import wraps
+import logging
+from rest_framework.views import APIView
+from util.models import RateLimitConfiguration
+
+
+LOGGER = logging.getLogger(__name__)
+
+
+def _check_throttles_decorator(func):
+    """Decorator for `APIView.check_throttles`.
+
+    The decorated function will first check model-based config
+    to see if rate limiting is disabled; if so, it skips
+    the throttle check.  Otherwise, it calls the original
+    function to enforce rate-limiting.
+
+    Arguments:
+        func (function): The function to decorate.
+
+    Returns:
+        The decorated function.
+
+    """
+    @wraps(func)
+    def _decorated(*args, **kwargs):
+        # Skip the throttle check entirely if we've disabled rate limiting.
+        # Otherwise, perform the checks (as usual)
+        if RateLimitConfiguration.current().enabled:
+            return func(*args, **kwargs)
+        else:
+            msg = "Rate limiting is disabled because `RateLimitConfiguration` is not enabled."
+            LOGGER.info(msg)
+            return
+
+    return _decorated
+
+
+def can_disable_rate_limit(clz):
+    """Class decorator that allows rate limiting to be disabled.
+
+    Arguments:
+        clz (class): The APIView subclass to decorate.
+
+    Returns:
+        class: the decorated class.
+
+    Example Usage:
+        >>> from rest_framework.views import APIView
+        >>> @can_disable_rate_limit
+        >>> class MyApiView(APIView):
+        >>>     pass
+
+    """
+    # No-op if the class isn't a Django Rest Framework view.
+    if not issubclass(clz, APIView):
+        msg = (
+            u"{clz} is not a Django Rest Framework APIView subclass."
+        ).format(clz=clz)
+        LOGGER.warning(msg)
+        return clz
+
+    # If we ARE explicitly disabling rate limiting,
+    # modify the class to always allow requests.
+    # Note that this overrides both rate limiting applied
+    # for the particular view, as well as global rate limits
+    # configured in Django settings.
+    if hasattr(clz, 'check_throttles'):
+        clz.check_throttles = _check_throttles_decorator(clz.check_throttles)
+
+    return clz

common/djangoapps/util/migrations/0001_initial.py

@@ -0,0 +1,72 @@
+# -*- coding: utf-8 -*-
+import datetime
+from south.db import db
+from south.v2 import SchemaMigration
+from django.db import models
+
+
+class Migration(SchemaMigration):
+
+    def forwards(self, orm):
+        # Adding model 'RateLimitConfiguration'
+        db.create_table('util_ratelimitconfiguration', (
+            ('id', self.gf('django.db.models.fields.AutoField')(primary_key=True)),
+            ('change_date', self.gf('django.db.models.fields.DateTimeField')(auto_now_add=True, blank=True)),
+            ('changed_by', self.gf('django.db.models.fields.related.ForeignKey')(to=orm['auth.User'], null=True, on_delete=models.PROTECT)),
+            ('enabled', self.gf('django.db.models.fields.BooleanField')(default=False)),
+        ))
+        db.send_create_signal('util', ['RateLimitConfiguration'])
+
+
+    def backwards(self, orm):
+        # Deleting model 'RateLimitConfiguration'
+        db.delete_table('util_ratelimitconfiguration')
+
+
+    models = {
+        'auth.group': {
+            'Meta': {'object_name': 'Group'},
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'name': ('django.db.models.fields.CharField', [], {'unique': 'True', 'max_length': '80'}),
+            'permissions': ('django.db.models.fields.related.ManyToManyField', [], {'to': "orm['auth.Permission']", 'symmetrical': 'False', 'blank': 'True'})
+        },
+        'auth.permission': {
+            'Meta': {'ordering': "('content_type__app_label', 'content_type__model', 'codename')", 'unique_together': "(('content_type', 'codename'),)", 'object_name': 'Permission'},
+            'codename': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
+            'content_type': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['contenttypes.ContentType']"}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'name': ('django.db.models.fields.CharField', [], {'max_length': '50'})
+        },
+        'auth.user': {
+            'Meta': {'object_name': 'User'},
+            'date_joined': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now'}),
+            'email': ('django.db.models.fields.EmailField', [], {'max_length': '75', 'blank': 'True'}),
+            'first_name': ('django.db.models.fields.CharField', [], {'max_length': '30', 'blank': 'True'}),
+            'groups': ('django.db.models.fields.related.ManyToManyField', [], {'to': "orm['auth.Group']", 'symmetrical': 'False', 'blank': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'is_active': ('django.db.models.fields.BooleanField', [], {'default': 'True'}),
+            'is_staff': ('django.db.models.fields.BooleanField', [], {'default': 'False'}),
+            'is_superuser': ('django.db.models.fields.BooleanField', [], {'default': 'False'}),
+            'last_login': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now'}),
+            'last_name': ('django.db.models.fields.CharField', [], {'max_length': '30', 'blank': 'True'}),
+            'password': ('django.db.models.fields.CharField', [], {'max_length': '128'}),
+            'user_permissions': ('django.db.models.fields.related.ManyToManyField', [], {'to': "orm['auth.Permission']", 'symmetrical': 'False', 'blank': 'True'}),
+            'username': ('django.db.models.fields.CharField', [], {'unique': 'True', 'max_length': '30'})
+        },
+        'contenttypes.contenttype': {
+            'Meta': {'ordering': "('name',)", 'unique_together': "(('app_label', 'model'),)", 'object_name': 'ContentType', 'db_table': "'django_content_type'"},
+            'app_label': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'model': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
+            'name': ('django.db.models.fields.CharField', [], {'max_length': '100'})
+        },
+        'util.ratelimitconfiguration': {
+            'Meta': {'object_name': 'RateLimitConfiguration'},
+            'change_date': ('django.db.models.fields.DateTimeField', [], {'auto_now_add': 'True', 'blank': 'True'}),
+            'changed_by': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['auth.User']", 'null': 'True', 'on_delete': 'models.PROTECT'}),
+            'enabled': ('django.db.models.fields.BooleanField', [], {'default': 'False'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'})
+        }
+    }
+
+    complete_apps = ['util']

common/djangoapps/util/migrations/0002_default_rate_limit_config.py

@@ -0,0 +1,64 @@
+# -*- coding: utf-8 -*-
+import datetime
+from south.db import db
+from south.v2 import DataMigration
+from django.db import models
+
+
+class Migration(DataMigration):
+
+    def forwards(self, orm):
+        """Ensure that rate limiting is enabled by default. """
+        orm['util.RateLimitConfiguration'].objects.create(enabled=True)
+
+    def backwards(self, orm):
+        pass
+
+    models = {
+        'auth.group': {
+            'Meta': {'object_name': 'Group'},
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'name': ('django.db.models.fields.CharField', [], {'unique': 'True', 'max_length': '80'}),
+            'permissions': ('django.db.models.fields.related.ManyToManyField', [], {'to': "orm['auth.Permission']", 'symmetrical': 'False', 'blank': 'True'})
+        },
+        'auth.permission': {
+            'Meta': {'ordering': "('content_type__app_label', 'content_type__model', 'codename')", 'unique_together': "(('content_type', 'codename'),)", 'object_name': 'Permission'},
+            'codename': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
+            'content_type': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['contenttypes.ContentType']"}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'name': ('django.db.models.fields.CharField', [], {'max_length': '50'})
+        },
+        'auth.user': {
+            'Meta': {'object_name': 'User'},
+            'date_joined': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now'}),
+            'email': ('django.db.models.fields.EmailField', [], {'max_length': '75', 'blank': 'True'}),
+            'first_name': ('django.db.models.fields.CharField', [], {'max_length': '30', 'blank': 'True'}),
+            'groups': ('django.db.models.fields.related.ManyToManyField', [], {'to': "orm['auth.Group']", 'symmetrical': 'False', 'blank': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'is_active': ('django.db.models.fields.BooleanField', [], {'default': 'True'}),
+            'is_staff': ('django.db.models.fields.BooleanField', [], {'default': 'False'}),
+            'is_superuser': ('django.db.models.fields.BooleanField', [], {'default': 'False'}),
+            'last_login': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now'}),
+            'last_name': ('django.db.models.fields.CharField', [], {'max_length': '30', 'blank': 'True'}),
+            'password': ('django.db.models.fields.CharField', [], {'max_length': '128'}),
+            'user_permissions': ('django.db.models.fields.related.ManyToManyField', [], {'to': "orm['auth.Permission']", 'symmetrical': 'False', 'blank': 'True'}),
+            'username': ('django.db.models.fields.CharField', [], {'unique': 'True', 'max_length': '30'})
+        },
+        'contenttypes.contenttype': {
+            'Meta': {'ordering': "('name',)", 'unique_together': "(('app_label', 'model'),)", 'object_name': 'ContentType', 'db_table': "'django_content_type'"},
+            'app_label': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'model': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
+            'name': ('django.db.models.fields.CharField', [], {'max_length': '100'})
+        },
+        'util.ratelimitconfiguration': {
+            'Meta': {'object_name': 'RateLimitConfiguration'},
+            'change_date': ('django.db.models.fields.DateTimeField', [], {'auto_now_add': 'True', 'blank': 'True'}),
+            'changed_by': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['auth.User']", 'null': 'True', 'on_delete': 'models.PROTECT'}),
+            'enabled': ('django.db.models.fields.BooleanField', [], {'default': 'False'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'})
+        }
+    }
+
+    complete_apps = ['util']
+    symmetrical = True

common/djangoapps/util/models.py

@@ -1 +1,14 @@
-# Create your models here.
+"""Models for the util app. """
+from config_models.models import ConfigurationModel
+
+
+class RateLimitConfiguration(ConfigurationModel):
+    """Configuration flag to enable/disable rate limiting.
+
+    Applies to Django Rest Framework views.
+
+    This is useful for disabling rate limiting for performance tests.
+    When enabled, it will disable rate limiting on any view decorated
+    with the `can_disable_rate_limit` class decorator.
+    """
+    pass

common/djangoapps/util/tests/test_disable_rate_limit.py

@@ -0,0 +1,55 @@
+"""Tests for disabling rate limiting. """
+import unittest
+from django.test import TestCase
+from django.core.cache import cache
+from django.conf import settings
+import mock
+
+from rest_framework.views import APIView
+from rest_framework.throttling import BaseThrottle
+from rest_framework.exceptions import Throttled
+
+from util.disable_rate_limit import can_disable_rate_limit
+from util.models import RateLimitConfiguration
+
+
+class FakeThrottle(BaseThrottle):
+    def allow_request(self, request, view):
+        return False
+
+
+@can_disable_rate_limit
+class FakeApiView(APIView):
+    authentication_classes = []
+    permission_classes = []
+    throttle_classes = [FakeThrottle]
+
+
+@unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
+class DisableRateLimitTest(TestCase):
+    """Check that we can disable rate limiting for perf testing. """
+
+    def setUp(self):
+        cache.clear()
+        self.view = FakeApiView()
+
+    def test_enable_rate_limit(self):
+        # Enable rate limiting using model-based config
+        RateLimitConfiguration.objects.create(enabled=True)
+
+        # By default, should enforce rate limiting
+        # Since our fake throttle always rejects requests,
+        # we should expect the request to be rejected.
+        request = mock.Mock()
+        with self.assertRaises(Throttled):
+            self.view.check_throttles(request)
+
+    def test_disable_rate_limit(self):
+        # Disable rate limiting using model-based config
+        RateLimitConfiguration.objects.create(enabled=False)
+
+        # With rate-limiting disabled, the request
+        # should get through.  The `check_throttles()` call
+        # should return without raising an exception.
+        request = mock.Mock()
+        self.view.check_throttles(request)