Sleep schedule: store 'next check' timestamp in UTC

SQLite doesn't parse the timezone info, so timestamps should always be in
UTC.

internal/manager/persistence/worker_sleep_schedule.go

@@ -63,6 +63,11 @@ func (db *DB) SetWorkerSleepSchedule(ctx context.Context, workerUUID string, sch
 	schedule.WorkerID = worker.ID
 	schedule.Worker = worker
 
+	// Only store timestamps in UTC.
+	if schedule.NextCheck.Location() != time.UTC {
+		schedule.NextCheck = schedule.NextCheck.UTC()
+	}
+
 	tx := db.gormDB.WithContext(ctx).
 		Clauses(clause.OnConflict{
 			Columns:   []clause.Column{{Name: "worker_id"}},
@@ -73,6 +78,11 @@ func (db *DB) SetWorkerSleepSchedule(ctx context.Context, workerUUID string, sch
 }
 
 func (db *DB) SetWorkerSleepScheduleNextCheck(ctx context.Context, schedule *SleepSchedule) error {
+	// Only store timestamps in UTC.
+	if schedule.NextCheck.Location() != time.UTC {
+		schedule.NextCheck = schedule.NextCheck.UTC()
+	}
+
 	tx := db.gormDB.WithContext(ctx).
 		Select("next_check").
 		Updates(schedule)
@@ -92,10 +102,12 @@ func (db *DB) FetchSleepScheduleWorker(ctx context.Context, schedule *SleepSched
 
 // FetchSleepSchedulesToCheck returns the sleep schedules that are due for a check.
 func (db *DB) FetchSleepSchedulesToCheck(ctx context.Context) ([]*SleepSchedule, error) {
-	log.Trace().Msg("fetching sleep schedules that need checking")
-
 	now := db.gormDB.NowFunc()
 
+	log.Debug().
+		Str("timeout", now.String()).
+		Msg("fetching sleep schedules that need checking")
+
 	schedules := []*SleepSchedule{}
 	tx := db.gormDB.WithContext(ctx).
 		Model(&SleepSchedule{}).

internal/manager/persistence/worker_sleep_schedule_test.go

@@ -243,7 +243,7 @@ func TestFetchSleepSchedulesToCheck(t *testing.T) {
 	ctx, finish, db := persistenceTestFixtures(t, 1*time.Second)
 	defer finish()
 
-	mockedNow := mustParseTime("2022-06-07T11:14:47+02:00")
+	mockedNow := mustParseTime("2022-06-07T11:14:47+02:00").UTC()
 	mockedPast := mockedNow.Add(-10 * time.Second)
 	mockedFuture := mockedNow.Add(10 * time.Second)
 

internal/manager/sleep_scheduler/calculations.go

@@ -69,7 +69,7 @@ func calculateNextCheck(now time.Time, schedule *persistence.SleepSchedule) time
 
 	nextChecks := []time.Time{
 		// Always check at the end of the day.
-		calcNext(persistence.TimeOfDay{Hour: 24, Minute: 0}),
+		endOfDay(now),
 	}
 
 	// No start time means "start of the day", which is already covered by
@@ -96,3 +96,8 @@ func earliestTime(timestamps []time.Time) time.Time {
 	}
 	return earliest
 }
+
+// endOfDay returns the next midnight at UTC.
+func endOfDay(now time.Time) time.Time {
+	return time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.UTC).AddDate(0, 0, 1)
+}

internal/manager/sleep_scheduler/sleep_scheduler_test.go

@@ -232,12 +232,11 @@ type TestMocks struct {
 func (m *TestMocks) todayAt(hour, minute int) time.Time {
 	now := m.clock.Now()
 	return time.Date(now.Year(), now.Month(), now.Day(), hour, minute, 0, 0, now.Location())
-
 }
 
 // endOfDay returns midnight of the day after whatever the mocked clock's "now" is set to.
 func (m *TestMocks) endOfDay() time.Time {
-	now := m.clock.Now()
+	now := m.clock.Now().UTC()
 	return time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location()).AddDate(0, 0, 1)
 }