fix(unified-storage): use continue token containing both formats for dualwriter (#106525)

pkg/setting/setting.go

@@ -551,6 +551,7 @@ type Cfg struct {
 
 	// Unified Storage
 	UnifiedStorage                             map[string]UnifiedStorageConfig
+	MaxPageSizeBytes                           int
 	IndexPath                                  string
 	IndexWorkers                               int
 	IndexMaxBatchSize                          int

pkg/setting/setting_unified_storage.go

@@ -51,6 +51,7 @@ func (cfg *Cfg) setUnifiedStorageConfig() {
 
 	// Set indexer config for unified storaae
 	section := cfg.Raw.Section("unified_storage")
+	cfg.MaxPageSizeBytes = section.Key("max_page_size_bytes").MustInt(0)
 	cfg.IndexPath = section.Key("index_path").String()
 	cfg.IndexWorkers = section.Key("index_workers").MustInt(10)
 	cfg.IndexMaxBatchSize = section.Key("index_max_batch_size").MustInt(100)

pkg/storage/legacysql/dualwrite/dualwriter.go

@@ -67,31 +67,106 @@ func (d *dualWriter) Get(ctx context.Context, name string, options *metav1.GetOp
 }
 
 func (d *dualWriter) List(ctx context.Context, options *metainternalversion.ListOptions) (runtime.Object, error) {
-	// If we read from unified, we can just do that and return.
-	if d.readUnified {
-		return d.unified.List(ctx, options)
-	}
-	// If legacy is still the main store, lets first read from it.
-	legacyList, err := d.legacy.List(ctx, options)
+	// Always work on *copies* so we never mutate the caller's ListOptions.
+	var (
+		legacyOptions  = options.DeepCopy()
+		unifiedOptions = options.DeepCopy()
+		log            = logging.FromContext(ctx).With("method", "List")
+	)
+
+	legacyToken, unifiedToken, err := parseContinueTokens(options.Continue)
 	if err != nil {
 		return nil, err
 	}
-	// Once we have successfully listed from legacy, we can check if we want to fail on a unified list.
-	// If we allow the unified list to fail, we can do it in the background and return.
-	if d.errorIsOK {
-		go func(ctxBg context.Context, cancel context.CancelFunc) {
-			defer cancel()
-			if _, err := d.unified.List(ctxBg, options); err != nil {
-				log := logging.FromContext(ctxBg).With("method", "List")
-				log.Error("failed background LIST to unified", "err", err)
-			}
-		}(context.WithTimeout(context.WithoutCancel(ctx), backgroundReqTimeout))
-		return legacyList, nil
-	}
-	// If it's not okay to fail, we have to check it in the foreground.
-	if _, err := d.unified.List(ctx, options); err != nil {
+
+	legacyOptions.Continue = legacyToken
+	unifiedOptions.Continue = unifiedToken
+
+	// If we read from unified, we can just do that and return.
+	if d.readUnified {
+		unifiedList, err := d.unified.List(ctx, unifiedOptions)
+		if err != nil {
 			return nil, err
 		}
+		unifiedMeta, err := meta.ListAccessor(unifiedList)
+		if err != nil {
+			return nil, fmt.Errorf("failed to access legacy List MetaData: %w", err)
+		}
+		unifiedMeta.SetContinue(buildContinueToken("", unifiedMeta.GetContinue()))
+		return unifiedList, nil
+	}
+
+	// In some cases, the unified token might be there but legacy token is empty (i.e. finished iteration).
+	// This can happen, as unified storage iteration is doing paging not only based on the provided limit,
+	// but also based on the response size. This check prevents starting the new iteration again.
+	if options.Continue != "" && legacyToken == "" {
+		return nil, nil
+	}
+
+	// In some cases, where the stores are not in sync yet, the unified storage continue token might already
+	// be empty, while the legacy one is not, as it has more data. In that case we don't want to issue a new
+	// request with an empty continue token, resulting in getting the first page again.
+	// nolint:staticcheck
+	shouldDoUnifiedRequest := true
+	if options.Continue != "" && unifiedToken == "" {
+		shouldDoUnifiedRequest = false
+	}
+
+	// If legacy is still the main store, lets first read from it.
+	legacyList, err := d.legacy.List(ctx, legacyOptions)
+	if err != nil {
+		return nil, err
+	}
+	legacyMeta, err := meta.ListAccessor(legacyList)
+	if err != nil {
+		return nil, fmt.Errorf("failed to access legacy List MetaData: %w", err)
+	}
+	legacyToken = legacyMeta.GetContinue()
+
+	// Once we have successfully listed from legacy, we can check if we want to fail on a unified list.
+	// If we allow the unified list to fail, we can do it in the background and return.
+	if d.errorIsOK && shouldDoUnifiedRequest {
+		// We would like to get continue token from unified storage, but
+		// don't want to wait for unified storage too long, since we're calling
+		// unified-storage asynchronously.
+		out := make(chan string, 1)
+		go func(ctxBg context.Context, cancel context.CancelFunc) {
+			defer cancel()
+			defer close(out)
+			unifiedList, err := d.unified.List(ctxBg, unifiedOptions)
+			if err != nil {
+				log.Error("failed background LIST to unified", "err", err)
+				return
+			}
+			unifiedMeta, err := meta.ListAccessor(unifiedList)
+			if err != nil {
+				log.Error("failed background LIST to unified", "err",
+					fmt.Errorf("failed to access unified List MetaData: %w", err))
+			}
+			out <- unifiedMeta.GetContinue()
+		}(context.WithTimeout(context.WithoutCancel(ctx), backgroundReqTimeout))
+		select {
+		case unifiedToken = <-out:
+		case <-time.After(300 * time.Millisecond):
+			log.Warn("timeout while waiting on the unified storage continue token")
+			break
+		}
+		legacyMeta.SetContinue(buildContinueToken(legacyToken, unifiedToken))
+		return legacyList, nil
+	}
+	if shouldDoUnifiedRequest {
+		// If it's not okay to fail, we have to check it in the foreground.
+		unifiedList, err := d.unified.List(ctx, unifiedOptions)
+		if err != nil {
+			return nil, err
+		}
+		unifiedMeta, err := meta.ListAccessor(unifiedList)
+		if err != nil {
+			return nil, fmt.Errorf("failed to access unified List MetaData: %w", err)
+		}
+		unifiedToken = unifiedMeta.GetContinue()
+	}
+	legacyMeta.SetContinue(buildContinueToken(legacyToken, unifiedToken))
 	return legacyList, nil
 }
 

pkg/storage/legacysql/dualwrite/dualwriter_continue_token.go

@@ -0,0 +1,33 @@
+package dualwrite
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strings"
+)
+
+// parseContinueTokens splits a dualwriter continue token (legacy, unified) if we received one.
+// If we receive a single token not separated by a comma, we return the token as-is as a legacy
+// token and an empty unified token. This is to ensure a smooth transition to the new token format.
+func parseContinueTokens(token string) (string, string, error) {
+	if token == "" {
+		return "", "", nil
+	}
+	decodedToken, err := base64.StdEncoding.DecodeString(token)
+	if err != nil {
+		return "", "", fmt.Errorf("failed to decode dualwriter continue token: %w", err)
+	}
+	decodedTokens := strings.Split(string(decodedToken), ",")
+	if len(decodedTokens) > 1 {
+		return decodedTokens[0], decodedTokens[1], nil
+	}
+	return token, "", nil
+}
+
+func buildContinueToken(legacyToken, unifiedToken string) string {
+	if legacyToken == "" && unifiedToken == "" {
+		return ""
+	}
+	return base64.StdEncoding.EncodeToString([]byte(
+		strings.Join([]string{legacyToken, unifiedToken}, ",")))
+}

pkg/storage/legacysql/dualwrite/dualwriter_continue_token_test.go

@@ -0,0 +1,98 @@
+package dualwrite
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseContinueTokens(t *testing.T) {
+	tcs := []struct {
+		name         string
+		token        string
+		legacyToken  string
+		unifiedToken string
+	}{
+		{
+			name:         "Should handle empty token",
+			token:        "",
+			legacyToken:  "",
+			unifiedToken: "",
+		},
+		{
+			name:         "Should handle legacy token",
+			token:        "MXwy",
+			legacyToken:  "MXwy",
+			unifiedToken: "",
+		},
+		{
+			name: "Should handle new token format",
+			// both slots taken 'MXwy,eyJvIjoxLCJ2IjoxNzQ5NTY1NTU4MDc4OTkwLCJzIjpmYWxzZX0='
+			token:        "TVh3eSxleUp2SWpveExDSjJJam94TnpRNU5UWTFOVFU0TURjNE9Ua3dMQ0p6SWpwbVlXeHpaWDA9",
+			legacyToken:  "MXwy",
+			unifiedToken: "eyJvIjoxLCJ2IjoxNzQ5NTY1NTU4MDc4OTkwLCJzIjpmYWxzZX0=",
+		},
+		{
+			name: "Should handle new token with only unified token (mode >= 3)",
+			// first slot empty ',eyJvIjoxLCJ2IjoxNzQ5NTY1NTU4MDc4OTkwLCJzIjpmYWxzZX0='
+			token:        "LGV5SnZJam94TENKMklqb3hOelE1TlRZMU5UVTRNRGM0T1Rrd0xDSnpJanBtWVd4elpYMD0=",
+			legacyToken:  "",
+			unifiedToken: "eyJvIjoxLCJ2IjoxNzQ5NTY1NTU4MDc4OTkwLCJzIjpmYWxzZX0=",
+		},
+	}
+
+	for _, tc := range tcs {
+		t.Run(tc.name, func(t *testing.T) {
+			legacyToken, unifiedToken, err := parseContinueTokens(tc.token)
+			require.NoError(t, err)
+			require.Equal(t, legacyToken, tc.legacyToken)
+			require.Equal(t, unifiedToken, tc.unifiedToken)
+		})
+	}
+}
+
+func TestBuildContinueToken(t *testing.T) {
+	tcs := []struct {
+		name          string
+		legacyToken   string
+		unifiedToken  string
+		shouldBeEmpty bool
+	}{
+		{
+			name:         "Should handle both tokens",
+			legacyToken:  "abc",
+			unifiedToken: "xyz",
+		},
+		{
+			name:        "Should handle legacy token standalone",
+			legacyToken: "abc",
+		},
+		{
+			name:         "Should handle unified token standalone",
+			unifiedToken: "xyz",
+		},
+		{
+			name:          "Should handle both tokens empty",
+			shouldBeEmpty: true,
+		},
+	}
+	for _, tc := range tcs {
+		t.Run(tc.name, func(t *testing.T) {
+			token := buildContinueToken(tc.legacyToken, tc.unifiedToken)
+			legacyToken, unifiedToken, err := parseContinueTokens(token)
+			require.NoError(t, err)
+			require.Equal(t, legacyToken, tc.legacyToken)
+			require.Equal(t, unifiedToken, tc.unifiedToken)
+			if tc.shouldBeEmpty {
+				require.Equal(t, "", token)
+			}
+		})
+	}
+}
+
+func TestInvalidToken(t *testing.T) {
+	// nolint: gosec
+	invalidToken := "325232ff4fF->"
+	_, _, err := parseContinueTokens(invalidToken)
+	require.Error(t, err)
+}

pkg/storage/unified/resource/server.go

@@ -198,6 +198,8 @@ type ResourceServerOptions struct {
 	storageMetrics *StorageMetrics
 
 	IndexMetrics *BleveIndexMetrics
+
+	MaxPageSizeBytes int
 }
 
 func NewResourceServer(opts ResourceServerOptions) (ResourceServer, error) {
@@ -222,6 +224,11 @@ func NewResourceServer(opts ResourceServerOptions) (ResourceServer, error) {
 		}
 	}
 
+	if opts.MaxPageSizeBytes <= 0 {
+		// By default, we use 2MB for the page size.
+		opts.MaxPageSizeBytes = 1024 * 1024 * 2
+	}
+
 	// Initialize the blob storage
 	blobstore := opts.Blob.Backend
 	if blobstore == nil {
@@ -263,6 +270,7 @@ func NewResourceServer(opts ResourceServerOptions) (ResourceServer, error) {
 		cancel:           cancel,
 		storageMetrics:   opts.storageMetrics,
 		indexMetrics:     opts.IndexMetrics,
+		maxPageSizeBytes: opts.MaxPageSizeBytes,
 	}
 
 	if opts.Search.Resources != nil {
@@ -307,6 +315,8 @@ type server struct {
 	// init checking
 	once    sync.Once
 	initErr error
+
+	maxPageSizeBytes int
 }
 
 // Init implements ResourceServer.
@@ -791,7 +801,7 @@ func (s *server) List(ctx context.Context, req *resourcepb.ListRequest) (*resour
 	if req.Limit < 1 {
 		req.Limit = 50 // default max 50 items in a page
 	}
-	maxPageBytes := 1024 * 1024 * 2 // 2mb/page
+	maxPageBytes := s.maxPageSizeBytes
 	pageBytes := 0
 	rsp := &resourcepb.ListResponse{}
 

pkg/storage/unified/sql/server.go

@@ -43,6 +43,12 @@ func NewResourceServer(db infraDB.DB, cfg *setting.Cfg,
 		opts.Blob.URL = "file:///" + dir
 	}
 
+	// This is mostly for testing, being able to influence when we paginate
+	// based on the page size during tests.
+	unifiedStorageCfg := cfg.SectionWithEnvOverrides("unified_storage")
+	maxPageSizeBytes := unifiedStorageCfg.Key("max_page_size_bytes")
+	opts.MaxPageSizeBytes = maxPageSizeBytes.MustInt(0)
+
 	eDB, err := dbimpl.ProvideResourceDB(db, cfg, tracer)
 	if err != nil {
 		return nil, err

pkg/tests/apis/folder/folders_test.go

@@ -177,6 +177,38 @@ func TestIntegrationFoldersApp(t *testing.T) {
 		}))
 	})
 
+	// This is a general test for the unified storage list operation. We don't have a common test
+	// directory for now, so we (search and storage) keep it here as we own this part of the tests.
+	t.Run("make sure list works with continue tokens", func(t *testing.T) {
+		modes := []grafanarest.DualWriterMode{
+			grafanarest.Mode1,
+			grafanarest.Mode2,
+			grafanarest.Mode3,
+			grafanarest.Mode4,
+			grafanarest.Mode5,
+		}
+		for _, mode := range modes {
+			t.Run(fmt.Sprintf("mode %d", mode), func(t *testing.T) {
+				doListFoldersTest(t, apis.NewK8sTestHelper(t, testinfra.GrafanaOpts{
+					AppModeProduction:    true,
+					DisableAnonymous:     true,
+					APIServerStorageType: "unified",
+					UnifiedStorageConfig: map[string]setting.UnifiedStorageConfig{
+						folders.RESOURCEGROUP: {
+							DualWriterMode: mode,
+						},
+					},
+					// We set it to 1 here, so we always get forced pagination based on the response size.
+					UnifiedStorageMaxPageSizeBytes: 1,
+					EnableFeatureToggles: []string{
+						featuremgmt.FlagKubernetesClientDashboardsFolders,
+						featuremgmt.FlagNestedFolders,
+					},
+				}), mode)
+			})
+		}
+	})
+
 	t.Run("when creating a folder it should trim leading and trailing spaces", func(t *testing.T) {
 		doCreateEnsureTitleIsTrimmedTest(t, apis.NewK8sTestHelper(t, testinfra.GrafanaOpts{
 			AppModeProduction:    true,
@@ -488,6 +520,65 @@ func doCreateCircularReferenceFolderTest(t *testing.T, helper *apis.K8sTestHelpe
 	require.Equal(t, 400, create.Response.StatusCode)
 }
 
+func doListFoldersTest(t *testing.T, helper *apis.K8sTestHelper, mode grafanarest.DualWriterMode) {
+	client := helper.GetResourceClient(apis.ResourceClientArgs{
+		User: helper.Org1.Admin,
+		GVR:  gvr,
+	})
+	foldersCount := 3
+	for i := 0; i < foldersCount; i++ {
+		payload, err := json.Marshal(map[string]interface{}{
+			"title": fmt.Sprintf("Test-%d", i),
+			"uid":   fmt.Sprintf("uid-%d", i),
+		})
+		require.NoError(t, err)
+		parentCreate := apis.DoRequest(helper, apis.RequestParams{
+			User:   client.Args.User,
+			Method: http.MethodPost,
+			Path:   "/api/folders",
+			Body:   payload,
+		}, &folder.Folder{})
+		require.NotNil(t, parentCreate.Result)
+		require.Equal(t, http.StatusOK, parentCreate.Response.StatusCode)
+	}
+	fetchedFolders, fetchItemsPerCall := checkListRequest(t, 1, client)
+	require.Equal(t, []string{"uid-0", "uid-1", "uid-2"}, fetchedFolders)
+	require.Equal(t, []int{1, 1, 1}, fetchItemsPerCall[:3])
+
+	// Now let's see if the iterator also works when we are limited by the page size, which should be set
+	// to 1 byte for this test. We only need to check that if we test unified storage as the primary storage,
+	// as legacy doesn't have such a page size limit.
+	if mode == grafanarest.Mode3 || mode == grafanarest.Mode4 || mode == grafanarest.Mode5 {
+		t.Run("check page size iterator", func(t *testing.T) {
+			fetchedFolders, fetchItemsPerCall := checkListRequest(t, 3, client)
+			require.Equal(t, []string{"uid-0", "uid-1", "uid-2"}, fetchedFolders)
+			require.Equal(t, []int{1, 1, 1}, fetchItemsPerCall[:3])
+		})
+	}
+}
+
+func checkListRequest(t *testing.T, limit int64, client *apis.K8sResourceClient) ([]string, []int) {
+	fetchedFolders := make([]string, 0, 3)
+	fetchItemsPerCall := make([]int, 0, 3)
+	continueToken := ""
+	for {
+		res, err := client.Resource.List(context.Background(), metav1.ListOptions{
+			Limit:    limit,
+			Continue: continueToken,
+		})
+		require.NoError(t, err)
+		fetchItemsPerCall = append(fetchItemsPerCall, len(res.Items))
+		for _, item := range res.Items {
+			fetchedFolders = append(fetchedFolders, item.GetName())
+		}
+		continueToken = res.GetContinue()
+		if continueToken == "" {
+			break
+		}
+	}
+	return fetchedFolders, fetchItemsPerCall
+}
+
 func TestIntegrationFolderCreatePermissions(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping integration test")

pkg/tests/testinfra/testinfra.go

@@ -492,6 +492,12 @@ func CreateGrafDir(t *testing.T, opts GrafanaOpts) (string, string) {
 			require.NoError(t, err)
 		}
 	}
+	if opts.UnifiedStorageMaxPageSizeBytes > 0 {
+		section, err := getOrCreateSection("unified_storage")
+		require.NoError(t, err)
+		_, err = section.NewKey("max_page_size_bytes", fmt.Sprintf("%d", opts.UnifiedStorageMaxPageSizeBytes))
+		require.NoError(t, err)
+	}
 	if opts.PermittedProvisioningPaths != "" {
 		_, err = pathsSect.NewKey("permitted_provisioning_paths", opts.PermittedProvisioningPaths)
 		require.NoError(t, err)
@@ -556,6 +562,7 @@ type GrafanaOpts struct {
 	QueryRetries                          int64
 	GrafanaComAPIURL                      string
 	UnifiedStorageConfig                  map[string]setting.UnifiedStorageConfig
+	UnifiedStorageMaxPageSizeBytes        int
 	PermittedProvisioningPaths            string
 	GrafanaComSSOAPIToken                 string
 	LicensePath                           string