Include timezone write when updating events; Write updated gcal timezone if only event change (#20435)

## Addresses #20431 

https://www.loom.com/share/0d88eceb8fb44ef3bec70d2b0dc7479c?sid=350bb4c2-2abe-4b80-b99f-ef6c8109efac

- Include timezone write when updating events
- Write updated gcal timezone to Fleet events, even if it's the only
change
- Have frontend handle `"UTC"` being set as timezone as if it were `nil`
- Small cleanups
 
- [x] Added/updated tests
- [x] Manual QA for all new/changed functionality

---------

Co-authored-by: Jacob Shandling <jacob@fleetdm.com>

ee/server/calendar/google_calendar.go

@@ -261,7 +261,7 @@ func (c *GoogleCalendar) Configure(userEmail string) error {
 	return nil
 }
 
-func (c *GoogleCalendar) GetAndUpdateEvent(event *fleet.CalendarEvent, genBodyFn func(conflict bool) (body string, ok bool, err error)) (
+func (c *GoogleCalendar) GetAndUpdateEvent(event *fleet.CalendarEvent, genBodyFn func(conflict bool) (body string, updated bool, err error)) (
 	*fleet.CalendarEvent, bool, error,
 ) {
 	// We assume that the Fleet event has not already ended. We will simply return it if it has not been modified.
@@ -269,11 +269,26 @@ func (c *GoogleCalendar) GetAndUpdateEvent(event *fleet.CalendarEvent, genBodyFn
 	if err != nil {
 		return nil, false, err
 	}
+
+	// Set current calendar instance timezone to the latest from google calendar.
+	c.location, err = getTimezone(c)
+	if err != nil {
+		return nil, false, err
+	}
+	tzUpdated := c.location.String() != event.TimeZone
+
 	gEvent, err := c.config.API.GetEvent(details.ID, details.ETag)
+
 	var deleted, channelStopped bool
 	switch {
 	// http.StatusNotModified is returned sometimes, but not always, so we need to check ETag explicitly later
 	case googleapi.IsNotModified(err):
+		if tzUpdated {
+			// this condition occurs when the event itself hasn't been updated, but the calendar timezone
+			// has been, so update the Fleet event's timezone
+			event.TimeZone = c.location.String()
+			return event, true, nil
+		}
 		return event, false, nil
 	// http.StatusNotFound should be very rare -- Google keeps events for a while after they are deleted
 	case isNotFound(err):
@@ -284,6 +299,12 @@ func (c *GoogleCalendar) GetAndUpdateEvent(event *fleet.CalendarEvent, genBodyFn
 	if !deleted && gEvent.Status != "cancelled" {
 		if details.ETag != "" && details.ETag == gEvent.Etag {
 			// Event was not modified
+			if tzUpdated {
+				// this condition occurs when the event itself hasn't been updated, but the calendar timezone
+				// has been, so just update the event's timezone
+				event.TimeZone = c.location.String()
+				return event, true, nil
+			}
 			return event, false, nil
 		}
 		if gEvent.End == nil || (gEvent.End.DateTime == "" && gEvent.End.Date == "") {
@@ -593,12 +614,12 @@ func adjustEventTimes(endTime time.Time, dayEnd time.Time) (eventStart time.Time
 func getTimezone(gCal *GoogleCalendar) (location *time.Location, err error) {
 	config := gCal.config
 	// "The ID of the user’s timezone." https://developers.google.com/calendar/api/v3/reference/settings
-	tz, err := config.API.GetSetting("timezone")
+	gCalTz, err := config.API.GetSetting("timezone")
 	if err != nil {
 		return nil, ctxerr.Wrap(config.Context, err, "retrieving Google calendar timezone")
 	}
 
-	return getLocation(tz.Value, config), nil
+	return getLocation(gCalTz.Value, config), nil
 }
 
 func getLocation(tz string, config *GoogleCalendarConfig) *time.Location {
@@ -616,6 +637,7 @@ func (c *GoogleCalendar) googleEventToFleetEvent(startTime time.Time, endTime ti
 	resourceID string) (
 	*fleet.CalendarEvent, error,
 ) {
+
 	fleetEvent := &fleet.CalendarEvent{}
 	fleetEvent.StartTime = startTime
 	fleetEvent.EndTime = endTime

ee/server/calendar/google_calendar_test.go

@@ -2,16 +2,17 @@ package calendar
 
 import (
 	"context"
+	"net/http"
+	"os"
+	"testing"
+	"time"
+
 	"github.com/fleetdm/fleet/v4/server/fleet"
 	"github.com/go-kit/log"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/api/calendar/v3"
 	"google.golang.org/api/googleapi"
-	"net/http"
-	"os"
-	"testing"
-	"time"
 )
 
 const (
@@ -202,6 +203,8 @@ func TestGoogleCalendar_GetAndUpdateEvent(t *testing.T) {
 	const baseETag = "event-eTag"
 	const baseEventID = "event-id"
 	const baseResourceID = "resource-id"
+	const baseTzName = "America/New_York"
+	baseTzLocation, _ := time.LoadLocation(baseTzName)
 	mockAPI.GetEventFunc = func(id, eTag string) (*calendar.Event, error) {
 		assert.Equal(t, baseEventID, id)
 		assert.Equal(t, baseETag, eTag)
@@ -209,6 +212,9 @@ func TestGoogleCalendar_GetAndUpdateEvent(t *testing.T) {
 			Etag: baseETag, // ETag matches -- no modifications to event
 		}, nil
 	}
+	mockAPI.GetSettingFunc = func(name string) (*calendar.Setting, error) {
+		return &calendar.Setting{Value: baseTzName}, nil
+	}
 	genBodyFn := func(bool) (string, bool, error) {
 		t.Error("genBodyFn should not be called")
 		return "event-body", false, nil
@@ -217,11 +223,12 @@ func TestGoogleCalendar_GetAndUpdateEvent(t *testing.T) {
 	err := cal.Configure(baseUserEmail)
 	assert.NoError(t, err)
 
-	eventStartTime := time.Now().UTC()
+	eventStartTime := time.Now().In(baseTzLocation)
 	event := &fleet.CalendarEvent{
 		StartTime: eventStartTime,
-		EndTime:   time.Now().Add(time.Hour),
+		EndTime:   time.Now().Add(time.Hour).In(baseTzLocation),
 		Data:      []byte(`{"ID":"` + baseEventID + `","ETag":"` + baseETag + `"}`),
+		TimeZone:  baseTzName,
 	}
 
 	// ETag matches
@@ -316,16 +323,19 @@ func TestGoogleCalendar_GetAndUpdateEvent(t *testing.T) {
 	assert.Error(t, err)
 
 	// Event has been modified, with custom timezone.
-	tzId := "Africa/Kinshasa"
-	location, _ := time.LoadLocation(tzId)
-	startTime = time.Now().Add(time.Minute).Truncate(time.Second).In(location)
-	endTime = time.Now().Add(time.Hour).Truncate(time.Second).In(location)
+	newTzName := "Africa/Kinshasa"
+	newTzLocation, _ := time.LoadLocation(newTzName)
+	mockAPI.GetSettingFunc = func(name string) (*calendar.Setting, error) {
+		return &calendar.Setting{Value: newTzName}, nil
+	}
+	startTime = time.Now().Add(time.Minute).Truncate(time.Second).In(newTzLocation)
+	endTime = time.Now().Add(time.Hour).Truncate(time.Second).In(newTzLocation)
 	mockAPI.GetEventFunc = func(id, eTag string) (*calendar.Event, error) {
 		return &calendar.Event{
 			Id:    baseEventID,
 			Etag:  "new-eTag",
-			Start: &calendar.EventDateTime{DateTime: startTime.UTC().Format(time.RFC3339), TimeZone: tzId},
-			End:   &calendar.EventDateTime{DateTime: endTime.Format(time.RFC3339), TimeZone: tzId},
+			Start: &calendar.EventDateTime{DateTime: startTime.UTC().Format(time.RFC3339), TimeZone: newTzName},
+			End:   &calendar.EventDateTime{DateTime: endTime.Format(time.RFC3339), TimeZone: newTzName},
 		}, nil
 	}
 	retrievedEvent, updated, err = cal.GetAndUpdateEvent(event, genBodyFn)
@@ -341,9 +351,6 @@ func TestGoogleCalendar_GetAndUpdateEvent(t *testing.T) {
 	mockAPI.GetEventFunc = func(id, eTag string) (*calendar.Event, error) {
 		return nil, &googleapi.Error{Code: http.StatusNotFound}
 	}
-	mockAPI.GetSettingFunc = func(name string) (*calendar.Setting, error) {
-		return &calendar.Setting{Value: "UTC"}, nil
-	}
 	mockAPI.ListEventsFunc = func(timeMin, timeMax string) (*calendar.Events, error) {
 		return &calendar.Events{}, nil
 	}
@@ -383,7 +390,7 @@ func TestGoogleCalendar_GetAndUpdateEvent(t *testing.T) {
 	assert.Equal(t, uuid, retrievedEvent.UUID)
 	assert.Equal(t, baseUserEmail, retrievedEvent.Email)
 	newEventDate := calculateNewEventDate(eventStartTime)
-	expectedStartTime := time.Date(newEventDate.Year(), newEventDate.Month(), newEventDate.Day(), startHour, 0, 0, 0, time.UTC)
+	expectedStartTime := time.Date(newEventDate.Year(), newEventDate.Month(), newEventDate.Day(), startHour, 0, 0, 0, newTzLocation)
 	assert.Equal(t, expectedStartTime.UTC(), retrievedEvent.StartTime.UTC())
 	assert.Equal(t, expectedStartTime.Add(eventLength).UTC(), retrievedEvent.EndTime.UTC())
 	assert.True(t, eventCreated)

frontend/pages/DashboardPage/DashboardPage.tsx

@@ -660,7 +660,6 @@ const DashboardPage = ({ router, location }: IDashboardProps): JSX.Element => {
         isSoftwareEnabled={isSoftwareEnabled}
         software={software}
         teamId={currentTeamId}
-        pageIndex={softwarePageIndex}
         navTabIndex={softwareNavTabIndex}
         onTabChange={onSoftwareTabChange}
         onQueryChange={onSoftwareQueryChange}

frontend/pages/DashboardPage/cards/Software/Software.tsx

@@ -23,7 +23,6 @@ interface ISoftwareCardProps {
   isSoftwareEnabled?: boolean;
   software?: ISoftwareResponse;
   teamId?: number;
-  pageIndex: number;
   navTabIndex: number;
   onTabChange: (index: number, last: number, event: Event) => boolean | void;
   onQueryChange?:

frontend/pages/hosts/details/cards/HostSummary/HostSummary.tsx

@@ -364,19 +364,20 @@ const HostSummary = ({
       DATE_FNS_FORMAT_STRINGS.dateAtTime
     );
 
-    const tip = timezone ? (
-      <>
-        End user&apos;s time zone:
-        <br />
-        (GMT{starts_at.slice(-6)}) {timezone.replace("_", " ")}
-      </>
-    ) : (
-      <>
-        End user&apos;s timezone unavailable.
-        <br />
-        Displaying in UTC.
-      </>
-    );
+    const tip =
+      timezone && timezone !== "UTC" ? (
+        <>
+          End user&apos;s time zone:
+          <br />
+          (GMT{starts_at.slice(-6)}) {timezone.replace("_", " ")}
+        </>
+      ) : (
+        <>
+          End user&apos;s timezone unavailable.
+          <br />
+          Displaying in UTC.
+        </>
+      );
 
     return (
       <DataSet

server/fleet/hosts.go

@@ -745,7 +745,7 @@ type HostMaintenanceWindow struct {
 	//  StartsAt is the start time of the future maintenance window, retrieved from calendar_events,
 	//  represented as a time.Time in the host's associated google calendar user's timezone, which is represented as a time.Location
 	StartsAt time.Time `json:"starts_at" db:"start_time"`
-	// TimeZone is the IANA timezone of the user's google calendar, retrieved from calendar_evants
+	// TimeZone is the IANA timezone of the user's google calendar, retrieved from calendar_events
 	TimeZone *string `json:"timezone" db:"timezone"`
 }