Part two

inbox/events/abstract.py

@@ -1,6 +1,6 @@
 import abc
 import datetime
-from typing import Dict, List, Optional
+from typing import Dict, Iterable, List, Optional
 
 from inbox.events.util import CalendarSyncResponse
 from inbox.logging import get_logger
@@ -39,7 +39,7 @@ def sync_calendars(self) -> CalendarSyncResponse:
     @abc.abstractmethod
     def sync_events(
         self, calendar_uid: str, sync_from_time: Optional[datetime.datetime] = None
-    ) -> List[Event]:
+    ) -> Iterable[Event]:
         """
         Fetch event data for an individual calendar.
 
@@ -49,7 +49,7 @@ def sync_events(
                     changed since this time.
 
         Returns:
-            A list of uncommited Event instances
+            An iterable of uncommited Event instances
         """
         raise NotImplementedError()
 

inbox/events/google.py

@@ -73,7 +73,7 @@ def sync_calendars(self) -> CalendarSyncResponse:
 
     def sync_events(
         self, calendar_uid: str, sync_from_time: Optional[datetime.datetime] = None
-    ) -> List[Event]:
+    ) -> Iterable[Event]:
         """
         Fetch event data for an individual calendar.
 
@@ -88,22 +88,18 @@ def sync_events(
                 all event data.
 
         Returns:
-            A list of uncommited Event instances
+            A generator of uncommited Event instances
         """
-        updates = []
         raw_events = self._get_raw_events(calendar_uid, sync_from_time)
         read_only_calendar = self.calendars_table.get(calendar_uid, True)
         for raw_event in iterate_and_periodically_switch_to_gevent(raw_events):
             try:
-                parsed = parse_event_response(raw_event, read_only_calendar)
-                updates.append(parsed)
+                yield parse_event_response(raw_event, read_only_calendar)
             except (arrow.parser.ParserError, ValueError):
                 self.log.warning(
                     "Skipping unparseable event", exc_info=True, raw=raw_event
                 )
 
-        return updates
-
     def _get_raw_calendars(self) -> Iterable[Dict[str, Any]]:
         """Gets raw data for the user's calendars."""
         return self._get_resource_list(CALENDARS_URL)

inbox/events/microsoft/events_provider.py

@@ -110,7 +110,7 @@ def sync_calendars(self) -> CalendarSyncResponse:
 
     def sync_events(
         self, calendar_uid: str, sync_from_time: Optional[datetime.datetime] = None
-    ) -> List[Event]:
+    ) -> Iterable[Event]:
         """
         Fetch event data for an individual calendar.
 
@@ -120,15 +120,14 @@ def sync_events(
                     changed since this time.
 
         Returns:
-            A list of uncommited Event instances
+            An iterator of uncommited Event instances
         """
         if sync_from_time:
             # this got here from the database, we store them as naive
             # UTC in the database. The code downstream is timezone aware so
             # we attach timezone here.
             sync_from_time = sync_from_time.replace(tzinfo=pytz.UTC)
 
-        updates = []
         raw_events = cast(
             Iterable[MsGraphEvent],
             self.client.iter_events(
@@ -142,16 +141,14 @@ def sync_events(
                 continue
 
             event = parse_event(raw_event, read_only=read_only)
-            updates.append(event)
+            yield event
 
             if isinstance(event, RecurringEvent):
                 exceptions, cancellations = self._get_event_overrides(
                     raw_event, event, read_only=read_only
                 )
-                updates.extend(exceptions)
-                updates.extend(cancellations)
-
-        return updates
+                yield from exceptions
+                yield from cancellations
 
     def _get_event_overrides(
         self, raw_master_event: MsGraphEvent, master_event: RecurringEvent, *, read_only

inbox/events/remote_sync.py

@@ -1,5 +1,5 @@
 from datetime import datetime, timedelta
-from typing import Any, List, Tuple, Type
+from typing import Any, Iterable, List, Tuple, Type
 
 import more_itertools
 from requests.exceptions import HTTPError
@@ -167,7 +167,11 @@ def handle_calendar_updates(
 
 
 def handle_event_updates(
-    namespace_id: int, calendar_id: int, events: List[Event], log: Any, db_session: Any
+    namespace_id: int,
+    calendar_id: int,
+    events: Iterable[Event],
+    log: Any,
+    db_session: Any,
 ) -> None:
     """Persists new or updated Event objects to the database."""
     added_count = 0

tests/events/test_google_events.py

@@ -265,7 +265,7 @@ def test_event_parsing():
     provider = GoogleEventsProvider(1, 1)
     provider.calendars_table = {"uid": False}
     provider._get_raw_events = mock.MagicMock(return_value=raw_response)
-    updates = provider.sync_events("uid", 1)
+    updates = list(provider.sync_events("uid", 1))
 
     # deleted events are actually only marked as
     # cancelled. Look for them in the updates stream.
@@ -317,7 +317,7 @@ def test_event_parsing():
     # This is a read-only calendar
     provider.calendars_table = {"uid": True}
     provider._get_raw_events = mock.MagicMock(return_value=raw_response)
-    updates = provider.sync_events("uid", 1)
+    updates = list(provider.sync_events("uid", 1))
     assert len(updates) == 1
     assert updates[0].read_only is True
 
@@ -508,7 +508,7 @@ def test_handle_unparseable_dates():
     )
     provider = GoogleEventsProvider(1, 1)
     provider._get_raw_events = mock.MagicMock(return_value=raw_response)
-    updates = provider.sync_events("uid", 1)
+    updates = list(provider.sync_events("uid", 1))
     assert len(updates) == 0
 
 
@@ -856,5 +856,5 @@ def test_cancelled_override_creation():
 
     provider = GoogleEventsProvider(1, 1)
     provider._get_raw_events = mock.MagicMock(return_value=raw_response)
-    updates = provider.sync_events("uid", 1)
+    updates = list(provider.sync_events("uid", 1))
     assert updates[0].cancelled is True

tests/events/test_sync.py

@@ -71,7 +71,7 @@ def calendar_response_with_delete():
 
 def event_response(calendar_uid, sync_from_time):
     if calendar_uid == "first_calendar_uid":
-        return [
+        yield from [
             Event.create(
                 uid="first_event_uid", title="Plotting Meeting", **default_params
             ),
@@ -83,7 +83,7 @@ def event_response(calendar_uid, sync_from_time):
             ),
         ]
     else:
-        return [
+        yield from [
             Event.create(
                 uid="second_event_uid", title="Plotting Meeting", **default_params
             ),
@@ -95,7 +95,7 @@ def event_response(calendar_uid, sync_from_time):
 
 def event_response_with_update(calendar_uid, sync_from_time):
     if calendar_uid == "first_calendar_uid":
-        return [
+        yield from [
             Event.create(
                 uid="first_event_uid",
                 title="Top Secret Plotting Meeting",
@@ -110,12 +110,12 @@ def event_response_with_participants_update(calendar_uid, sync_from_time):
         new_events[0].participants = [
             {"name": "Johnny Thunders", "email": "[email protected]"}
         ]
-        return new_events
+        yield from new_events
 
 
 def event_response_with_delete(calendar_uid, sync_from_time):
     if calendar_uid == "first_calendar_uid":
-        return [
+        yield from [
             Event.create(uid="first_event_uid", status="cancelled", **default_params)
         ]