Make LFS http_client parallel within a batch. (#32369)

Signed-off-by: Royce Remer <royceremer@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

custom/conf/app.example.ini

@@ -2642,9 +2642,15 @@ LEVEL = Info
 ;; override the azure blob base path if storage type is azureblob
 ;AZURE_BLOB_BASE_PATH = lfs/
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; settings for Gitea's LFS client (eg: mirroring an upstream lfs endpoint)
+;;
 ;[lfs_client]
-;; When mirroring an upstream lfs endpoint, limit the number of pointers in each batch request to this number
+;; Limit the number of pointers in each batch request to this number
 ;BATCH_SIZE = 20
+;; Limit the number of concurrent upload/download operations within a batch
+;BATCH_OPERATION_CONCURRENCY = 3
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

go.mod

@@ -124,6 +124,7 @@ require (
 	golang.org/x/image v0.21.0
 	golang.org/x/net v0.30.0
 	golang.org/x/oauth2 v0.23.0
+	golang.org/x/sync v0.8.0
 	golang.org/x/sys v0.26.0
 	golang.org/x/text v0.19.0
 	golang.org/x/tools v0.26.0
@@ -316,7 +317,6 @@ require (
 	go.uber.org/zap v1.27.0 // indirect
 	golang.org/x/exp v0.0.0-20241009180824-f66d83c29e7c // indirect
 	golang.org/x/mod v0.21.0 // indirect
-	golang.org/x/sync v0.8.0 // indirect
 	golang.org/x/time v0.7.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20241021214115-324edc3d5d38 // indirect
 	gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc // indirect

modules/lfs/http_client.go

@@ -17,6 +17,8 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/proxy"
 	"code.gitea.io/gitea/modules/setting"
+
+	"golang.org/x/sync/errgroup"
 )
 
 // HTTPClient is used to communicate with the LFS server
@@ -113,6 +115,7 @@ func (c *HTTPClient) Upload(ctx context.Context, objects []Pointer, callback Upl
 	return c.performOperation(ctx, objects, nil, callback)
 }
 
+// performOperation takes a slice of LFS object pointers, batches them, and performs the upload/download operations concurrently in each batch
 func (c *HTTPClient) performOperation(ctx context.Context, objects []Pointer, dc DownloadCallback, uc UploadCallback) error {
 	if len(objects) == 0 {
 		return nil
@@ -133,30 +136,48 @@ func (c *HTTPClient) performOperation(ctx context.Context, objects []Pointer, dc
 		return fmt.Errorf("TransferAdapter not found: %s", result.Transfer)
 	}
 
+	errGroup, groupCtx := errgroup.WithContext(ctx)
+	errGroup.SetLimit(setting.LFSClient.BatchOperationConcurrency)
 	for _, object := range result.Objects {
+		errGroup.Go(func() error {
+			return performSingleOperation(groupCtx, object, dc, uc, transferAdapter)
+		})
+	}
+
+	// only the first error is returned, preserving legacy behavior before concurrency
+	return errGroup.Wait()
+}
+
+// performSingleOperation performs an LFS upload or download operation on a single object
+func performSingleOperation(ctx context.Context, object *ObjectResponse, dc DownloadCallback, uc UploadCallback, transferAdapter TransferAdapter) error {
+	// the response from a lfs batch api request for this specific object id contained an error
 	if object.Error != nil {
 		log.Trace("Error on object %v: %v", object.Pointer, object.Error)
+
+		// this was an 'upload' request inside the batch request
 		if uc != nil {
 			if _, err := uc(object.Pointer, object.Error); err != nil {
 				return err
 			}
 		} else {
+			// this was NOT an 'upload' request inside the batch request, meaning it must be a 'download' request
 			if err := dc(object.Pointer, nil, object.Error); err != nil {
 				return err
 			}
 		}
-			continue
+		// if the callback returns no err, then the error could be ignored, and the operations should continue
+		return nil
 	}
 
+	// the response from an lfs batch api request contained necessary upload/download fields to act upon
 	if uc != nil {
 		if len(object.Actions) == 0 {
 			log.Trace("%v already present on server", object.Pointer)
-				continue
+			return nil
 		}
 
 		link, ok := object.Actions["upload"]
 		if !ok {
-				log.Debug("%+v", object)
 			return errors.New("missing action 'upload'")
 		}
 
@@ -196,8 +217,6 @@ func (c *HTTPClient) performOperation(ctx context.Context, objects []Pointer, dc
 			return err
 		}
 	}
-	}
-
 	return nil
 }
 

modules/lfs/http_client_test.go

@@ -12,6 +12,8 @@ import (
 	"testing"
 
 	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -183,71 +185,61 @@ func TestHTTPClientDownload(t *testing.T) {
 
 	cases := []struct {
 		endpoint      string
-		expectederror string
+		expectedError string
 	}{
-		// case 0
 		{
 			endpoint:      "https://status-not-ok.io",
-			expectederror: io.ErrUnexpectedEOF.Error(),
+			expectedError: io.ErrUnexpectedEOF.Error(),
 		},
-		// case 1
 		{
 			endpoint:      "https://invalid-json-response.io",
-			expectederror: "invalid json",
+			expectedError: "invalid json",
 		},
-		// case 2
 		{
 			endpoint:      "https://valid-batch-request-download.io",
-			expectederror: "",
+			expectedError: "",
 		},
-		// case 3
 		{
 			endpoint:      "https://response-no-objects.io",
-			expectederror: "",
+			expectedError: "",
 		},
-		// case 4
 		{
 			endpoint:      "https://unknown-transfer-adapter.io",
-			expectederror: "TransferAdapter not found: ",
+			expectedError: "TransferAdapter not found: ",
 		},
-		// case 5
 		{
 			endpoint:      "https://error-in-response-objects.io",
-			expectederror: "Object not found",
+			expectedError: "Object not found",
 		},
-		// case 6
 		{
 			endpoint:      "https://empty-actions-map.io",
-			expectederror: "missing action 'download'",
+			expectedError: "missing action 'download'",
 		},
-		// case 7
 		{
 			endpoint:      "https://download-actions-map.io",
-			expectederror: "",
+			expectedError: "",
 		},
-		// case 8
 		{
 			endpoint:      "https://upload-actions-map.io",
-			expectederror: "missing action 'download'",
+			expectedError: "missing action 'download'",
 		},
-		// case 9
 		{
 			endpoint:      "https://verify-actions-map.io",
-			expectederror: "missing action 'download'",
+			expectedError: "missing action 'download'",
 		},
-		// case 10
 		{
 			endpoint:      "https://unknown-actions-map.io",
-			expectederror: "missing action 'download'",
+			expectedError: "missing action 'download'",
 		},
-		// case 11
 		{
 			endpoint:      "https://legacy-batch-request-download.io",
-			expectederror: "",
+			expectedError: "",
 		},
 	}
 
-	for n, c := range cases {
+	defer test.MockVariableValue(&setting.LFSClient.BatchOperationConcurrency, 3)()
+	for _, c := range cases {
+		t.Run(c.endpoint, func(t *testing.T) {
 			client := &HTTPClient{
 				client:   hc,
 				endpoint: c.endpoint,
@@ -265,11 +257,12 @@ func TestHTTPClientDownload(t *testing.T) {
 				assert.Equal(t, []byte("dummy"), b)
 				return nil
 			})
-		if len(c.expectederror) > 0 {
+			if c.expectedError != "" {
-			assert.True(t, strings.Contains(err.Error(), c.expectederror), "case %d: '%s' should contain '%s'", n, err.Error(), c.expectederror)
+				assert.ErrorContains(t, err, c.expectedError)
 			} else {
-			assert.NoError(t, err, "case %d", n)
+				assert.NoError(t, err)
 			}
+		})
 	}
 }
 
@@ -296,66 +289,57 @@ func TestHTTPClientUpload(t *testing.T) {
 
 	cases := []struct {
 		endpoint      string
-		expectederror string
+		expectedError string
 	}{
-		// case 0
 		{
 			endpoint:      "https://status-not-ok.io",
-			expectederror: io.ErrUnexpectedEOF.Error(),
+			expectedError: io.ErrUnexpectedEOF.Error(),
 		},
-		// case 1
 		{
 			endpoint:      "https://invalid-json-response.io",
-			expectederror: "invalid json",
+			expectedError: "invalid json",
 		},
-		// case 2
 		{
 			endpoint:      "https://valid-batch-request-upload.io",
-			expectederror: "",
+			expectedError: "",
 		},
-		// case 3
 		{
 			endpoint:      "https://response-no-objects.io",
-			expectederror: "",
+			expectedError: "",
 		},
-		// case 4
 		{
 			endpoint:      "https://unknown-transfer-adapter.io",
-			expectederror: "TransferAdapter not found: ",
+			expectedError: "TransferAdapter not found: ",
 		},
-		// case 5
 		{
 			endpoint:      "https://error-in-response-objects.io",
-			expectederror: "Object not found",
+			expectedError: "Object not found",
 		},
-		// case 6
 		{
 			endpoint:      "https://empty-actions-map.io",
-			expectederror: "",
+			expectedError: "",
 		},
-		// case 7
 		{
 			endpoint:      "https://download-actions-map.io",
-			expectederror: "missing action 'upload'",
+			expectedError: "missing action 'upload'",
 		},
-		// case 8
 		{
 			endpoint:      "https://upload-actions-map.io",
-			expectederror: "",
+			expectedError: "",
 		},
-		// case 9
 		{
 			endpoint:      "https://verify-actions-map.io",
-			expectederror: "missing action 'upload'",
+			expectedError: "missing action 'upload'",
 		},
-		// case 10
 		{
 			endpoint:      "https://unknown-actions-map.io",
-			expectederror: "missing action 'upload'",
+			expectedError: "missing action 'upload'",
 		},
 	}
 
-	for n, c := range cases {
+	defer test.MockVariableValue(&setting.LFSClient.BatchOperationConcurrency, 3)()
+	for _, c := range cases {
+		t.Run(c.endpoint, func(t *testing.T) {
 			client := &HTTPClient{
 				client:   hc,
 				endpoint: c.endpoint,
@@ -367,10 +351,11 @@ func TestHTTPClientUpload(t *testing.T) {
 			err := client.Upload(context.Background(), []Pointer{p}, func(p Pointer, objectError error) (io.ReadCloser, error) {
 				return io.NopCloser(new(bytes.Buffer)), objectError
 			})
-		if len(c.expectederror) > 0 {
+			if c.expectedError != "" {
-			assert.True(t, strings.Contains(err.Error(), c.expectederror), "case %d: '%s' should contain '%s'", n, err.Error(), c.expectederror)
+				assert.ErrorContains(t, err, c.expectedError)
 			} else {
-			assert.NoError(t, err, "case %d", n)
+				assert.NoError(t, err)
 			}
+		})
 	}
 }

modules/repository/repo.go

@@ -181,11 +181,12 @@ func StoreMissingLfsObjectsInRepository(ctx context.Context, repo *repo_model.Re
 
 	downloadObjects := func(pointers []lfs.Pointer) error {
 		err := lfsClient.Download(ctx, pointers, func(p lfs.Pointer, content io.ReadCloser, objectError error) error {
-			if objectError != nil {
 			if errors.Is(objectError, lfs.ErrObjectNotExist) {
-					log.Warn("Repo[%-v]: Ignore missing LFS object %-v: %v", repo, p, objectError)
+				log.Warn("Ignoring missing upstream LFS object %-v: %v", p, objectError)
 				return nil
 			}
+
+			if objectError != nil {
 				return objectError
 			}
 

modules/setting/lfs.go

@@ -29,6 +29,7 @@ var LFS = struct {
 // LFSClient represents configuration for Gitea's LFS clients, for example: mirroring upstream Git LFS
 var LFSClient = struct {
 	BatchSize                 int `ini:"BATCH_SIZE"`
+	BatchOperationConcurrency int `ini:"BATCH_OPERATION_CONCURRENCY"`
 }{}
 
 func loadLFSFrom(rootCfg ConfigProvider) error {
@@ -66,6 +67,11 @@ func loadLFSFrom(rootCfg ConfigProvider) error {
 		LFSClient.BatchSize = 20
 	}
 
+	if LFSClient.BatchOperationConcurrency < 1 {
+		// match the default git-lfs's `lfs.concurrenttransfers`
+		LFSClient.BatchOperationConcurrency = 3
+	}
+
 	LFS.HTTPAuthExpiry = sec.Key("LFS_HTTP_AUTH_EXPIRY").MustDuration(24 * time.Hour)
 
 	if !LFS.StartServer || !InstallLock {

modules/setting/lfs_test.go

@@ -114,4 +114,17 @@ BATCH_SIZE = 0
 	assert.NoError(t, loadLFSFrom(cfg))
 	assert.EqualValues(t, 100, LFS.MaxBatchSize)
 	assert.EqualValues(t, 20, LFSClient.BatchSize)
+	assert.EqualValues(t, 3, LFSClient.BatchOperationConcurrency)
+
+	iniStr = `
+[lfs_client]
+BATCH_SIZE = 50
+BATCH_OPERATION_CONCURRENCY = 10
+`
+	cfg, err = NewConfigProviderFromData(iniStr)
+	assert.NoError(t, err)
+
+	assert.NoError(t, loadLFSFrom(cfg))
+	assert.EqualValues(t, 50, LFSClient.BatchSize)
+	assert.EqualValues(t, 10, LFSClient.BatchOperationConcurrency)
 }