From 74968de6e3ff6e3756d3cbd1a6f153898054eb8a Mon Sep 17 00:00:00 2001
From: Victor Lyuboslavsky <victor@fleetdm.com>
Date: Mon, 1 Apr 2024 15:54:37 -0500
Subject: [PATCH] Enabling calendar clean up job to delete Google calendar
 events in parallel.

---
 cmd/fleet/calendar_cron.go | 48 +++++++++++++++++++++++++++-----------
 1 file changed, 34 insertions(+), 14 deletions(-)

diff --git a/cmd/fleet/calendar_cron.go b/cmd/fleet/calendar_cron.go
index 953747c602..553fa62c65 100644
--- a/cmd/fleet/calendar_cron.go
+++ b/cmd/fleet/calendar_cron.go
@@ -609,7 +609,7 @@ func cronCalendarEventsCleanup(ctx context.Context, ds fleet.Datastore, logger k
 	// If global setting is disabled, we remove all calendar events from the DB
 	// (we cannot delete the events from the user calendar because there's no configuration anymore).
 	if userCalendar == nil {
-		if err := deleteAllCalendarEvents(ctx, ds, nil, nil); err != nil {
+		if err := deleteAllCalendarEvents(ctx, ds, nil, nil, logger); err != nil {
 			return fmt.Errorf("delete all calendar events: %w", err)
 		}
 		// We've deleted all calendar events, nothing else to do.
@@ -630,7 +630,7 @@ func cronCalendarEventsCleanup(ctx context.Context, ds fleet.Datastore, logger k
 	}
 
 	for _, team := range teams {
-		if err := cleanupTeamCalendarEvents(ctx, ds, userCalendar, *team); err != nil {
+		if err := cleanupTeamCalendarEvents(ctx, ds, userCalendar, *team, logger); err != nil {
 			level.Info(logger).Log("msg", "delete team calendar events", "team_id", team.ID, "err", err)
 		}
 	}
@@ -644,12 +644,7 @@ func cronCalendarEventsCleanup(ctx context.Context, ds fleet.Datastore, logger k
 	if err != nil {
 		return fmt.Errorf("list out of date calendar events: %w", err)
 	}
-	for _, outOfDateCalendarEvent := range outOfDateCalendarEvents {
-		if err := deleteCalendarEvent(ctx, ds, userCalendar, outOfDateCalendarEvent); err != nil {
-			return fmt.Errorf("delete user calendar event: %w", err)
-		}
-	}
-
+	deleteCalendarEventsInParallel(ctx, ds, userCalendar, outOfDateCalendarEvents, logger)
 	return nil
 }
 
@@ -658,24 +653,49 @@ func deleteAllCalendarEvents(
 	ds fleet.Datastore,
 	userCalendar fleet.UserCalendar,
 	teamID *uint,
+	logger kitlog.Logger,
 ) error {
 	calendarEvents, err := ds.ListCalendarEvents(ctx, teamID)
 	if err != nil {
 		return fmt.Errorf("list calendar events: %w", err)
 	}
-	for _, calendarEvent := range calendarEvents {
-		if err := deleteCalendarEvent(ctx, ds, userCalendar, calendarEvent); err != nil {
-			return fmt.Errorf("delete user calendar event: %w", err)
-		}
-	}
+	deleteCalendarEventsInParallel(ctx, ds, userCalendar, calendarEvents, logger)
 	return nil
 }
 
+func deleteCalendarEventsInParallel(
+	ctx context.Context, ds fleet.Datastore, userCalendar fleet.UserCalendar, calendarEvents []*fleet.CalendarEvent, logger kitlog.Logger,
+) {
+	if len(calendarEvents) > 0 {
+		const consumers = 20
+		calendarEventCh := make(chan *fleet.CalendarEvent)
+		var wg sync.WaitGroup
+		for i := 0; i < consumers; i++ {
+			wg.Add(+1)
+			go func() {
+				defer wg.Done()
+				for calEvent := range calendarEventCh {
+					if err := deleteCalendarEvent(ctx, ds, userCalendar, calEvent); err != nil {
+						level.Error(logger).Log("msg", "delete user calendar event", "err", err)
+						continue
+					}
+				}
+			}()
+		}
+		for _, outOfDateCalendarEvent := range calendarEvents {
+			calendarEventCh <- outOfDateCalendarEvent
+		}
+		close(calendarEventCh)
+		wg.Wait()
+	}
+}
+
 func cleanupTeamCalendarEvents(
 	ctx context.Context,
 	ds fleet.Datastore,
 	userCalendar fleet.UserCalendar,
 	team fleet.Team,
+	logger kitlog.Logger,
 ) error {
 	teamFeatureEnabled := team.Config.Integrations.GoogleCalendar != nil && team.Config.Integrations.GoogleCalendar.Enable
 
@@ -692,7 +712,7 @@ func cleanupTeamCalendarEvents(
 		// so we want to cleanup all calendar events for the team.
 	}
 
-	return deleteAllCalendarEvents(ctx, ds, userCalendar, &team.ID)
+	return deleteAllCalendarEvents(ctx, ds, userCalendar, &team.ID, logger)
 }
 
 func deleteCalendarEvent(ctx context.Context, ds fleet.Datastore, userCalendar fleet.UserCalendar, calendarEvent *fleet.CalendarEvent) error {