use delta queries for calendar events (#2154)

## Description

Hacks the beta version call into the events api
when iterating through items, allowing us to run
delta-based queries for calendar events.

## Does this PR need a docs update or release note?

- [x] ⛔ No 

## Type of change

- [x] 🌻 Feature

## Issue(s)

* #2022

## Test Plan

- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/connector/data_collections_test.go

@@ -68,7 +68,7 @@ func (suite *ConnectorDataCollectionIntegrationSuite) TestExchangeDataCollection
 		getSelector func(t *testing.T) selectors.Selector
 	}{
 		{
-			name: suite.user + " Email",
+			name: "Email",
 			getSelector: func(t *testing.T) selectors.Selector {
 				sel := selectors.NewExchangeBackup(selUsers)
 				sel.Include(sel.MailFolders([]string{exchange.DefaultMailFolder}, selectors.PrefixMatch()))
@@ -77,7 +77,7 @@ func (suite *ConnectorDataCollectionIntegrationSuite) TestExchangeDataCollection
 			},
 		},
 		{
-			name: suite.user + " Contacts",
+			name: "Contacts",
 			getSelector: func(t *testing.T) selectors.Selector {
 				sel := selectors.NewExchangeBackup(selUsers)
 				sel.Include(sel.ContactFolders([]string{exchange.DefaultContactFolder}, selectors.PrefixMatch()))
@@ -86,7 +86,7 @@ func (suite *ConnectorDataCollectionIntegrationSuite) TestExchangeDataCollection
 			},
 		},
 		// {
-		// 	name: suite.user + " Events",
+		// 	name: "Events",
 		// 	getSelector: func(t *testing.T) selectors.Selector {
 		// 		sel := selectors.NewExchangeBackup(selUsers)
 		// 		sel.Include(sel.EventCalendars([]string{exchange.DefaultCalendar}, selectors.PrefixMatch()))

src/internal/connector/exchange/api/events.go

@@ -144,29 +144,25 @@ func (c Events) EnumerateContainers(
 // item pager
 // ---------------------------------------------------------------------------
 
-type eventWrapper struct {
-	models.EventCollectionResponseable
-}
-
-func (ew eventWrapper) GetOdataDeltaLink() *string {
-	return nil
-}
-
 var _ itemPager = &eventPager{}
 
+const (
+	eventBetaDeltaURLTemplate = "https://graph.microsoft.com/beta/users/%s/calendars/%s/events/delta"
+)
+
 type eventPager struct {
 	gs      graph.Servicer
-	builder *users.ItemCalendarsItemEventsRequestBuilder
-	options *users.ItemCalendarsItemEventsRequestBuilderGetRequestConfiguration
+	builder *users.ItemCalendarsItemEventsDeltaRequestBuilder
+	options *users.ItemCalendarsItemEventsDeltaRequestBuilderGetRequestConfiguration
 }
 
 func (p *eventPager) getPage(ctx context.Context) (pageLinker, error) {
 	resp, err := p.builder.Get(ctx, p.options)
-	return eventWrapper{resp}, err
+	return resp, err
 }
 
 func (p *eventPager) setNext(nextLink string) {
-	p.builder = users.NewItemCalendarsItemEventsRequestBuilder(nextLink, p.gs.Adapter())
+	p.builder = users.NewItemCalendarsItemEventsDeltaRequestBuilder(nextLink, p.gs.Adapter())
 }
 
 func (p *eventPager) valuesIn(pl pageLinker) ([]getIDAndAddtler, error) {
@@ -182,23 +178,54 @@ func (c Events) GetAddedAndRemovedItemIDs(
 		return nil, nil, DeltaUpdate{}, err
 	}
 
-	var errs *multierror.Error
+	var (
+		resetDelta bool
+		errs       *multierror.Error
+	)
 
-	options, err := optionsForEventsByCalendar([]string{"id"})
+	options, err := optionsForEventsByCalendarDelta([]string{"id"})
 	if err != nil {
 		return nil, nil, DeltaUpdate{}, err
 	}
 
-	builder := service.Client().UsersById(user).CalendarsById(calendarID).Events()
+	if len(oldDelta) > 0 {
+		builder := users.NewItemCalendarsItemEventsDeltaRequestBuilder(oldDelta, service.Adapter())
+		pgr := &eventPager{service, builder, options}
+
+		added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+		// note: happy path, not the error condition
+		if err == nil {
+			return added, removed, DeltaUpdate{deltaURL, false}, errs.ErrorOrNil()
+		}
+		// only return on error if it is NOT a delta issue.
+		// on bad deltas we retry the call with the regular builder
+		if graph.IsErrInvalidDelta(err) == nil {
+			return nil, nil, DeltaUpdate{}, err
+		}
+
+		resetDelta = true
+		errs = nil
+	}
+
+	// Graph SDK only supports delta queries against events on the beta version, so we're
+	// manufacturing use of the beta version url to make the call instead.
+	// See: https://learn.microsoft.com/ko-kr/graph/api/event-delta?view=graph-rest-beta&tabs=http
+	// Note that the delta item body is skeletal compared to the actual event struct.  Lucky
+	// for us, we only need the item ID.  As a result, even though we hacked the version, the
+	// response body parses properly into the v1.0 structs and complies with our wanted interfaces.
+	// Likewise, the NextLink and DeltaLink odata tags carry our hack forward, so the rest of the code
+	// works as intended (until, at least, we want to _not_ call the beta anymore).
+	rawURL := fmt.Sprintf(eventBetaDeltaURLTemplate, user, calendarID)
+	builder := users.NewItemCalendarsItemEventsDeltaRequestBuilder(rawURL, service.Adapter())
 	pgr := &eventPager{service, builder, options}
 
-	added, _, _, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
 	if err != nil {
 		return nil, nil, DeltaUpdate{}, err
 	}
 
 	// Events don't have a delta endpoint so just return an empty string.
-	return added, nil, DeltaUpdate{}, errs.ErrorOrNil()
+	return added, removed, DeltaUpdate{deltaURL, resetDelta}, errs.ErrorOrNil()
 }
 
 // ---------------------------------------------------------------------------

src/internal/connector/exchange/api/options.go

@@ -214,19 +214,19 @@ func optionsForContactFoldersItemDelta(
 }
 
 // optionsForEvents ensures a valid option inputs for `exchange.Events` when selected from within a Calendar
-func optionsForEventsByCalendar(
+func optionsForEventsByCalendarDelta(
 	moreOps []string,
-) (*users.ItemCalendarsItemEventsRequestBuilderGetRequestConfiguration, error) {
+) (*users.ItemCalendarsItemEventsDeltaRequestBuilderGetRequestConfiguration, error) {
 	selecting, err := buildOptions(moreOps, fieldsForEvents)
 	if err != nil {
 		return nil, err
 	}
 
-	requestParameters := &users.ItemCalendarsItemEventsRequestBuilderGetQueryParameters{
+	requestParameters := &users.ItemCalendarsItemEventsDeltaRequestBuilderGetQueryParameters{
 		Select: selecting,
 	}
 
-	options := &users.ItemCalendarsItemEventsRequestBuilderGetRequestConfiguration{
+	options := &users.ItemCalendarsItemEventsDeltaRequestBuilderGetRequestConfiguration{
 		QueryParameters: requestParameters,
 	}
 

src/internal/connector/exchange/data_collections_test.go

@@ -313,6 +313,13 @@ func (suite *DataCollectionsIntegrationSuite) TestDelta() {
 				selectors.PrefixMatch(),
 			)[0],
 		},
+		{
+			name: "Events",
+			scope: selectors.NewExchangeBackup(users).EventCalendars(
+				[]string{DefaultCalendar},
+				selectors.PrefixMatch(),
+			)[0],
+		},
 	}
 	for _, test := range tests {
 		suite.T().Run(test.name, func(t *testing.T) {

src/internal/operations/backup_integration_test.go

@@ -7,7 +7,7 @@ import (
 	"time"
 
 	"github.com/google/uuid"
-	msuser "github.com/microsoftgraph/msgraph-sdk-go/users"
+	"github.com/microsoftgraph/msgraph-sdk-go/users"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -507,7 +507,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchange() {
 	ctx, flush := tester.NewContext()
 	defer flush()
 
-	users := []string{suite.user}
+	owners := []string{suite.user}
 
 	tests := []struct {
 		name           string
@@ -520,7 +520,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchange() {
 		{
 			name: "Mail",
 			selector: func() *selectors.ExchangeBackup {
-				sel := selectors.NewExchangeBackup(users)
+				sel := selectors.NewExchangeBackup(owners)
 				sel.Include(sel.MailFolders([]string{exchange.DefaultMailFolder}, selectors.PrefixMatch()))
 				sel.DiscreteOwner = suite.user
 
@@ -534,7 +534,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchange() {
 		{
 			name: "Contacts",
 			selector: func() *selectors.ExchangeBackup {
-				sel := selectors.NewExchangeBackup(users)
+				sel := selectors.NewExchangeBackup(owners)
 				sel.Include(sel.ContactFolders([]string{exchange.DefaultContactFolder}, selectors.PrefixMatch()))
 				return sel
 			},
@@ -546,7 +546,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchange() {
 		{
 			name: "Calendar Events",
 			selector: func() *selectors.ExchangeBackup {
-				sel := selectors.NewExchangeBackup(users)
+				sel := selectors.NewExchangeBackup(owners)
 				sel.Include(sel.EventCalendars([]string{exchange.DefaultCalendar}, selectors.PrefixMatch()))
 				return sel
 			},
@@ -639,10 +639,12 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 		ffs        = control.Toggles{}
 		mb         = evmock.NewBus()
 		now        = common.Now()
-		users      = []string{suite.user}
+		owners     = []string{suite.user}
 		categories = map[path.CategoryType][]string{
 			path.EmailCategory:    exchange.MetadataFileNames(path.EmailCategory),
 			path.ContactsCategory: exchange.MetadataFileNames(path.ContactsCategory),
+			// TODO: not currently functioning; cannot retrieve generated calendars
+			// path.EventsCategory:   exchange.MetadataFileNames(path.EventsCategory),
 		}
 		container1      = fmt.Sprintf("%s%d_%s", incrementalsDestContainerPrefix, 1, now)
 		container2      = fmt.Sprintf("%s%d_%s", incrementalsDestContainerPrefix, 2, now)
@@ -688,6 +690,13 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 		)
 	}
 
+	eventDBF := func(id, timeStamp, subject, body string) []byte {
+		return mockconnector.GetMockEventWith(
+			suite.user, subject, body, body,
+			now, now, false)
+	}
+
+	// test data set
 	dataset := map[path.CategoryType]struct {
 		dbf   dataBuilderFunc
 		dests map[string]contDeets
@@ -706,8 +715,17 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 				container2: {},
 			},
 		},
+		// TODO: not currently functioning; cannot retrieve generated calendars
+		// path.EventsCategory: {
+		// 	dbf: eventDBF,
+		// 	dests: map[string]contDeets{
+		// 		container1: {},
+		// 		container2: {},
+		// 	},
+		// },
 	}
 
+	// populate initial test data
 	for category, gen := range dataset {
 		for destName := range gen.dests {
 			deets := generateContainerOfItems(
@@ -717,7 +735,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 				path.ExchangeService,
 				acct,
 				category,
-				selectors.NewExchangeRestore(users).Selector,
+				selectors.NewExchangeRestore(owners).Selector,
 				m365.AzureTenantID, suite.user, destName,
 				2,
 				gen.dbf)
@@ -726,6 +744,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 		}
 	}
 
+	// verify test data was populated, and track it for comparisons
 	for category, gen := range dataset {
 		qp := graph.QueryParams{
 			Category:      category,
@@ -752,7 +771,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 	// later on during the tests.  Putting their identifiers into the selector
 	// at this point is harmless.
 	containers := []string{container1, container2, container3, containerRename}
-	sel := selectors.NewExchangeBackup(users)
+	sel := selectors.NewExchangeBackup(owners)
 	sel.Include(
 		sel.MailFolders(containers, selectors.PrefixMatch()),
 		sel.ContactFolders(containers, selectors.PrefixMatch()),
@@ -788,7 +807,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 				toContainer := dataset[path.EmailCategory].dests[container1].containerID
 				fromContainer := dataset[path.EmailCategory].dests[container2].containerID
 
-				body := msuser.NewItemMailFoldersItemMovePostRequestBody()
+				body := users.NewItemMailFoldersItemMovePostRequestBody()
 				body.SetDestinationId(&toContainer)
 
 				_, err := gc.Service.
@@ -820,6 +839,11 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 							t,
 							cli.ContactFoldersById(containerID).Delete(ctx, nil),
 							"deleting a contacts folder")
+					case path.EventsCategory:
+						require.NoError(
+							t,
+							cli.CalendarsById(containerID).Delete(ctx, nil),
+							"deleting a calendar")
 					}
 				}
 			},
@@ -837,7 +861,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 						path.ExchangeService,
 						acct,
 						category,
-						selectors.NewExchangeRestore(users).Selector,
+						selectors.NewExchangeRestore(owners).Selector,
 						m365.AzureTenantID, suite.user, container3,
 						2,
 						gen.dbf)
@@ -897,6 +921,16 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 						body.SetDisplayName(&containerRename)
 						_, err = ccf.Patch(ctx, body, nil)
 						require.NoError(t, err, "updating contact folder name")
+
+					case path.EventsCategory:
+						ccf := cli.CalendarsById(containerID)
+
+						body, err := ccf.Get(ctx, nil)
+						require.NoError(t, err, "getting calendar")
+
+						body.SetName(&containerRename)
+						_, err = ccf.Patch(ctx, body, nil)
+						require.NoError(t, err, "updating calendar name")
 					}
 				}
 			},
@@ -926,6 +960,14 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 
 						_, err = cli.ContactFoldersById(containerID).Contacts().Post(ctx, body, nil)
 						require.NoError(t, err, "posting contact item")
+
+					case path.EventsCategory:
+						_, itemData := generateItemData(t, category, suite.user, eventDBF)
+						body, err := support.CreateEventFromBytes(itemData)
+						require.NoError(t, err, "transforming event bytes to eventable")
+
+						_, err = cli.CalendarsById(containerID).Events().Post(ctx, body, nil)
+						require.NoError(t, err, "posting events item")
 					}
 				}
 			},
@@ -955,6 +997,14 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 
 						err = cli.ContactsById(ids[0]).Delete(ctx, nil)
 						require.NoError(t, err, "deleting contact item: %s", support.ConnectorStackErrorTrace(err))
+
+					case path.EventsCategory:
+						ids, _, _, err := ac.Events().GetAddedAndRemovedItemIDs(ctx, suite.user, containerID, "")
+						require.NoError(t, err, "getting event ids")
+						require.NotEmpty(t, ids, "event ids in folder")
+
+						err = cli.CalendarsById(ids[0]).Delete(ctx, nil)
+						require.NoError(t, err, "deleting calendar: %s", support.ConnectorStackErrorTrace(err))
 					}
 				}
 			},

src/internal/operations/restore_test.go

@@ -198,9 +198,9 @@ func (suite *RestoreOpIntegrationSuite) SetupSuite() {
 	require.NotEmpty(t, bo.Results.BackupID)
 
 	suite.backupID = bo.Results.BackupID
-	// Discount metadata files (3 paths, 2 deltas) as
+	// Discount metadata files (3 paths, 3 deltas) as
 	// they are not part of the data restored.
-	suite.numItems = bo.Results.ItemsWritten - 5
+	suite.numItems = bo.Results.ItemsWritten - 6
 }
 
 func (suite *RestoreOpIntegrationSuite) TearDownSuite() {