Expand interfaces for components used during backup (#1731)

## Description

Expand interfaces for `GraphConnector.DataCollections` and `kopia.Wrapper.BackupCollections` to include parameters that will be needed during incremental backups. This patch only expands the interfaces, it does not add any extra functionality and the passed parameters are currently ignored.

In the future, passing nil for any of the new parameters should result in the current "full backup" behavior that Corso has. Passing values in these parameters should enable delta token-based incremental backups (assuming all the required data is there for the incremental backup)

## Type of change

- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 💻 CI/Deployment
- [x] 🐹 Trivial/Minor

## Issue(s)

* closes #1700 

## Test Plan

- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E

src/internal/connector/data_collections.go

@@ -24,8 +24,16 @@ import (
 // Data Collections
 // ---------------------------------------------------------------------------
 
-// DataCollections utility function to launch backup operations for exchange and onedrive
+// DataCollections utility function to launch backup operations for exchange and
-func (gc *GraphConnector) DataCollections(ctx context.Context, sels selectors.Selector) ([]data.Collection, error) {
+// onedrive. metadataCols contains any collections with metadata files that may
+// be useful for the current backup. Metadata can include things like delta
+// tokens or the previous backup's folder hierarchy. The absence of metadataCols
+// results in all data being pulled.
+func (gc *GraphConnector) DataCollections(
+	ctx context.Context,
+	sels selectors.Selector,
+	metadataCols []data.Collection,
+) ([]data.Collection, error) {
 	ctx, end := D.Span(ctx, "gc:dataCollections", D.Index("service", sels.Service.String()))
 	defer end()
 

src/internal/connector/data_collections_test.go

@@ -157,7 +157,7 @@ func (suite *ConnectorDataCollectionIntegrationSuite) TestInvalidUserForDataColl
 
 	for _, test := range tests {
 		suite.T().Run(test.name, func(t *testing.T) {
-			collections, err := connector.DataCollections(ctx, test.getSelector(t))
+			collections, err := connector.DataCollections(ctx, test.getSelector(t), nil)
 			assert.Error(t, err)
 			assert.Empty(t, collections)
 		})
@@ -542,6 +542,6 @@ func (suite *ConnectorCreateSharePointCollectionIntegrationSuite) TestCreateShar
 		selectors.PrefixMatch(),
 	))
 
-	_, err := gc.DataCollections(ctx, sel.Selector)
+	_, err := gc.DataCollections(ctx, sel.Selector, nil)
 	require.NoError(t, err)
 }

src/internal/connector/graph_connector_test.go

@@ -387,7 +387,7 @@ func runRestoreBackupTest(
 	t.Logf("Selective backup of %s\n", backupSel)
 
 	start = time.Now()
-	dcs, err := backupGC.DataCollections(ctx, backupSel)
+	dcs, err := backupGC.DataCollections(ctx, backupSel, nil)
 	require.NoError(t, err)
 
 	t.Logf("Backup enumeration complete in %v\n", time.Since(start))
@@ -855,7 +855,7 @@ func (suite *GraphConnectorIntegrationSuite) TestMultiFolderBackupDifferentNames
 			backupSel := backupSelectorForExpected(t, test.service, expectedDests)
 			t.Log("Selective backup of", backupSel)
 
-			dcs, err := backupGC.DataCollections(ctx, backupSel)
+			dcs, err := backupGC.DataCollections(ctx, backupSel, nil)
 			require.NoError(t, err)
 
 			t.Log("Backup enumeration complete")

src/internal/kopia/wrapper.go

@@ -493,8 +493,17 @@ func inflateDirTree(
 	return res, ownerCats, nil
 }
 
+// BackupCollections takes a set of collections and creates a kopia snapshot
+// with the data that they contain. previousSnapshots is used for incremental
+// backups and should represent the base snapshot from which metadata is sourced
+// from as well as any incomplete snapshot checkpoints that may contain more
+// recent data than the base snapshot. The absence of previousSnapshots causes a
+// complete backup of all data.
+//
+// TODO(ashmrtn): Use previousSnapshots parameter.
 func (w Wrapper) BackupCollections(
 	ctx context.Context,
+	previousSnapshots []*snapshot.Manifest,
 	collections []data.Collection,
 	service path.ServiceType,
 ) (*BackupStats, *details.Details, error) {

src/internal/kopia/wrapper_test.go

@@ -882,7 +882,12 @@ func (suite *KopiaIntegrationSuite) TestBackupCollections() {
 
 	for _, test := range table {
 		suite.T().Run(test.name, func(t *testing.T) {
-			stats, deets, err := suite.w.BackupCollections(suite.ctx, collections, path.ExchangeService)
+			stats, deets, err := suite.w.BackupCollections(
+				suite.ctx,
+				nil,
+				collections,
+				path.ExchangeService,
+			)
 			assert.NoError(t, err)
 
 			assert.Equal(t, test.expectedUploadedFiles, stats.TotalFileCount, "total files")
@@ -933,7 +938,12 @@ func (suite *KopiaIntegrationSuite) TestRestoreAfterCompressionChange() {
 	fp2, err := suite.testPath2.Append(dc2.Names[0], true)
 	require.NoError(t, err)
 
-	stats, deets, err := w.BackupCollections(ctx, []data.Collection{dc1, dc2}, path.ExchangeService)
+	stats, deets, err := w.BackupCollections(
+		ctx,
+		nil,
+		[]data.Collection{dc1, dc2},
+		path.ExchangeService,
+	)
 	require.NoError(t, err)
 	assert.Equal(t, path.ExchangeService.String(), deets.Tags[model.ServiceTag])
 
@@ -999,7 +1009,12 @@ func (suite *KopiaIntegrationSuite) TestBackupCollections_ReaderError() {
 		},
 	}
 
-	stats, deets, err := suite.w.BackupCollections(suite.ctx, collections, path.ExchangeService)
+	stats, deets, err := suite.w.BackupCollections(
+		suite.ctx,
+		nil,
+		collections,
+		path.ExchangeService,
+	)
 	require.NoError(t, err)
 
 	assert.Equal(t, 0, stats.ErrorCount)
@@ -1038,7 +1053,12 @@ func (suite *KopiaIntegrationSuite) TestBackupCollectionsHandlesNoCollections()
 			ctx, flush := tester.NewContext()
 			defer flush()
 
-			s, d, err := suite.w.BackupCollections(ctx, test.collections, path.UnknownService)
+			s, d, err := suite.w.BackupCollections(
+				ctx,
+				nil,
+				test.collections,
+				path.UnknownService,
+			)
 			require.NoError(t, err)
 
 			assert.Equal(t, BackupStats{}, *s)
@@ -1184,7 +1204,12 @@ func (suite *KopiaSimpleRepoIntegrationSuite) SetupTest() {
 		collections = append(collections, collection)
 	}
 
-	stats, deets, err := suite.w.BackupCollections(suite.ctx, collections, path.ExchangeService)
+	stats, deets, err := suite.w.BackupCollections(
+		suite.ctx,
+		nil,
+		collections,
+		path.ExchangeService,
+	)
 	require.NoError(t, err)
 	require.Equal(t, stats.ErrorCount, 0)
 	require.Equal(t, stats.TotalFileCount, expectedFiles)

src/internal/operations/backup.go

@@ -147,7 +147,7 @@ func (op *BackupOperation) Run(ctx context.Context) (err error) {
 	defer closer()
 	defer close(discoverCh)
 
-	cs, err := gc.DataCollections(ctx, op.Selectors)
+	cs, err := gc.DataCollections(ctx, op.Selectors, nil)
 	if err != nil {
 		err = errors.Wrap(err, "retrieving service data")
 		opStats.readErr = err
@@ -164,7 +164,7 @@ func (op *BackupOperation) Run(ctx context.Context) (err error) {
 	defer close(backupCh)
 
 	// hand the results to the consumer
-	opStats.k, backupDetails, err = op.kopia.BackupCollections(ctx, cs, op.Selectors.PathService())
+	opStats.k, backupDetails, err = op.kopia.BackupCollections(ctx, nil, cs, op.Selectors.PathService())
 	if err != nil {
 		err = errors.Wrap(err, "backing up service data")
 		opStats.writeErr = err