Handle more kinds of bad data in segment events.

common/djangoapps/track/views/segmentio.py

@@ -123,16 +123,16 @@ def track_segmentio_event(request):  # pylint: disable=too-many-statements
     full_segment_event = request.json
 
     # We mostly care about the properties
-    segment_properties = full_segment_event.get('properties', {})
+    segment_properties = _get_dict_value_with_default(full_segment_event, 'properties', {})
 
     # Start with the context provided by Segment in the "client" field if it exists
     # We should tightly control which fields actually get included in the event emitted.
-    segment_context = full_segment_event.get('context', {})
+    segment_context = _get_dict_value_with_default(full_segment_event, 'context', {})
 
     # Build up the event context by parsing fields out of the event received from Segment
     context = {}
 
-    library_name = segment_context.get('library', {}).get('name')
+    library_name = _get_dict_value_with_default(segment_context, 'library', {}).get('name')
     source_map = getattr(settings, 'TRACKING_SEGMENTIO_SOURCE_MAP', {})
     event_source = source_map.get(library_name)
     if not event_source:
@@ -268,3 +268,12 @@ def _get_segmentio_event_name(event_properties):
 def parse_iso8601_timestamp(timestamp):
     """Parse a particular type of ISO8601 formatted timestamp"""
     return parser.parse(timestamp)
+
+
+def _get_dict_value_with_default(dict_object, key, default):
+    """
+    Returns default if the dict doesn't have the key or if the value is Falsey.
+    Otherwise, returns the dict's value for the key.
+    """
+    value = dict_object.get(key, None)
+    return value if value else default

common/djangoapps/track/views/tests/base.py

@@ -60,6 +60,14 @@ def post_segmentio_event(self, **kwargs):
         )
         segmentio.track_segmentio_event(request)
 
+    def post_modified_segmentio_event(self, event):
+        """Post an externally-defined fake Segment event to the view that processes it"""
+        request = self.create_request(
+            data=json.dumps(event),
+            content_type='application/json'
+        )
+        segmentio.track_segmentio_event(request)
+
     def create_segmentio_event(self, **kwargs):
         """Populate a fake Segment event with data of interest"""
         action = kwargs.get('action', 'Track')

common/djangoapps/track/views/tests/test_segmentio.py

@@ -68,10 +68,46 @@ def test_segmentio_ignore_actions(self, action):
         self.post_segmentio_event(action=action)
         self.assert_no_events_emitted()
 
+    def test_segmentio_ignore_missing_context_entry(self):
+        sample_event_raw = self.create_segmentio_event()
+        del sample_event_raw['context']
+        self.post_modified_segmentio_event(sample_event_raw)
+        self.assert_no_events_emitted()
+
+    def test_segmentio_ignore_null_context_entry(self):
+        sample_event_raw = self.create_segmentio_event()
+        sample_event_raw['context'] = None
+        self.post_modified_segmentio_event(sample_event_raw)
+        self.assert_no_events_emitted()
+
+    def test_segmentio_ignore_missing_library_entry(self):
+        sample_event_raw = self.create_segmentio_event()
+        del sample_event_raw['context']['library']
+        self.post_modified_segmentio_event(sample_event_raw)
+        self.assert_no_events_emitted()
+
+    def test_segmentio_ignore_null_library_entry(self):
+        sample_event_raw = self.create_segmentio_event()
+        sample_event_raw['context']['library'] = None
+        self.post_modified_segmentio_event(sample_event_raw)
+        self.assert_no_events_emitted()
+
     def test_segmentio_ignore_unknown_libraries(self):
         self.post_segmentio_event(library_name='foo')
         self.assert_no_events_emitted()
 
+    @expect_failure_with_message(segmentio.ERROR_MISSING_NAME)
+    def test_segmentio_ignore_missing_properties_entry(self):
+        sample_event_raw = self.create_segmentio_event()
+        del sample_event_raw['properties']
+        self.post_modified_segmentio_event(sample_event_raw)
+
+    @expect_failure_with_message(segmentio.ERROR_MISSING_NAME)
+    def test_segmentio_ignore_null_properties_entry(self):
+        sample_event_raw = self.create_segmentio_event()
+        sample_event_raw['properties'] = None
+        self.post_modified_segmentio_event(sample_event_raw)
+
     @expect_failure_with_message(segmentio.ERROR_USER_NOT_EXIST)
     def test_no_user_for_user_id(self):
         self.post_segmentio_event(user_id=40)
@@ -148,43 +184,23 @@ def test_invalid_course_id(self):
     def test_missing_name(self):
         sample_event_raw = self.create_segmentio_event()
         del sample_event_raw['properties']['name']
-        request = self.create_request(
-            data=json.dumps(sample_event_raw),
-            content_type='application/json'
-        )
-
-        segmentio.track_segmentio_event(request)
+        self.post_modified_segmentio_event(sample_event_raw)
 
     @expect_failure_with_message(segmentio.ERROR_MISSING_DATA)
     def test_missing_data(self):
         sample_event_raw = self.create_segmentio_event()
         del sample_event_raw['properties']['data']
-        request = self.create_request(
-            data=json.dumps(sample_event_raw),
-            content_type='application/json'
-        )
-
-        segmentio.track_segmentio_event(request)
+        self.post_modified_segmentio_event(sample_event_raw)
 
     @expect_failure_with_message(segmentio.ERROR_MISSING_TIMESTAMP)
     def test_missing_timestamp(self):
         sample_event_raw = self.create_event_without_fields('timestamp')
-        request = self.create_request(
-            data=json.dumps(sample_event_raw),
-            content_type='application/json'
-        )
-
-        segmentio.track_segmentio_event(request)
+        self.post_modified_segmentio_event(sample_event_raw)
 
     @expect_failure_with_message(segmentio.ERROR_MISSING_RECEIVED_AT)
     def test_missing_received_at(self):
         sample_event_raw = self.create_event_without_fields('receivedAt')
-        request = self.create_request(
-            data=json.dumps(sample_event_raw),
-            content_type='application/json'
-        )
-
-        segmentio.track_segmentio_event(request)
+        self.post_modified_segmentio_event(sample_event_raw)
 
     def create_event_without_fields(self, *fields):
         """Create a fake event and remove some fields from it"""