lightning: refactor the backend package

Makefile

@@ -112,14 +112,14 @@ test: export ARGS=$$($(PACKAGES))
 test:
 	$(PREPARE_MOD)
 	@make failpoint-enable
-	$(GOTEST) $(RACEFLAG) -tags br_test,leak $(ARGS) || ( make failpoint-disable && exit 1 )
+	$(GOTEST) $(RACEFLAG) -tags leak $(ARGS) || ( make failpoint-disable && exit 1 )
 	@make failpoint-disable
 
 testcover: tools
 	mkdir -p "$(TEST_DIR)"
 	$(PREPARE_MOD)
 	@make failpoint-enable
-	$(GOTEST) -tags br_test -cover -covermode=count -coverprofile="$(TEST_DIR)/cov.unit.out" \
+	$(GOTEST) -cover -covermode=count -coverprofile="$(TEST_DIR)/cov.unit.out" \
 		$$($(COVERED_PACKAGES)) || ( make failpoint-disable && exit 1 )
 	@make failpoint-disable
 
@@ -186,7 +186,7 @@ static: prepare tools
 	@#   exhaustivestruct - Protobuf structs have hidden fields, like "XXX_NoUnkeyedLiteral"
 	@#         exhaustive - no need to check exhaustiveness of enum switch statements
 	@#              gosec - too many false positive
-	CGO_ENABLED=0 tools/bin/golangci-lint run --enable-all --build-tags br_test --deadline 120s \
+	CGO_ENABLED=0 tools/bin/golangci-lint run --enable-all --deadline 120s \
 		--disable gochecknoglobals \
 		--disable goimports \
 		--disable gofmt \

cmd/tidb-lightning-ctl/main.go

@@ -26,11 +26,14 @@ import (
 	"github.com/pingcap/errors"
 	"github.com/pingcap/kvproto/pkg/import_sstpb"
 
-	kv "github.com/pingcap/br/pkg/lightning/backend"
+	"github.com/pingcap/br/pkg/lightning/backend"
+	"github.com/pingcap/br/pkg/lightning/backend/importer"
+	"github.com/pingcap/br/pkg/lightning/backend/local"
 	"github.com/pingcap/br/pkg/lightning/checkpoints"
 	"github.com/pingcap/br/pkg/lightning/common"
 	"github.com/pingcap/br/pkg/lightning/config"
 	"github.com/pingcap/br/pkg/lightning/restore"
+	"github.com/pingcap/br/pkg/lightning/tikv"
 )
 
 func main() {
@@ -133,12 +136,12 @@ func run() error {
 }
 
 func compactCluster(ctx context.Context, cfg *config.Config, tls *common.TLS) error {
-	return kv.ForAllStores(
+	return tikv.ForAllStores(
 		ctx,
 		tls.WithHost(cfg.TiDB.PdAddr),
-		kv.StoreStateDisconnected,
-		func(c context.Context, store *kv.Store) error {
-			return kv.Compact(c, tls, store.Address, restore.FullLevelCompact)
+		tikv.StoreStateDisconnected,
+		func(c context.Context, store *tikv.Store) error {
+			return tikv.Compact(c, tls, store.Address, restore.FullLevelCompact)
 		},
 	)
 }
@@ -154,23 +157,23 @@ func switchMode(ctx context.Context, cfg *config.Config, tls *common.TLS, mode s
 		return errors.Errorf("invalid mode %s, must use %s or %s", mode, config.ImportMode, config.NormalMode)
 	}
 
-	return kv.ForAllStores(
+	return tikv.ForAllStores(
 		ctx,
 		tls.WithHost(cfg.TiDB.PdAddr),
-		kv.StoreStateDisconnected,
-		func(c context.Context, store *kv.Store) error {
-			return kv.SwitchMode(c, tls, store.Address, m)
+		tikv.StoreStateDisconnected,
+		func(c context.Context, store *tikv.Store) error {
+			return tikv.SwitchMode(c, tls, store.Address, m)
 		},
 	)
 }
 
 func fetchMode(ctx context.Context, cfg *config.Config, tls *common.TLS) error {
-	return kv.ForAllStores(
+	return tikv.ForAllStores(
 		ctx,
 		tls.WithHost(cfg.TiDB.PdAddr),
-		kv.StoreStateDisconnected,
-		func(c context.Context, store *kv.Store) error {
-			mode, err := kv.FetchMode(c, tls, store.Address)
+		tikv.StoreStateDisconnected,
+		func(c context.Context, store *tikv.Store) error {
+			mode, err := tikv.FetchMode(c, tls, store.Address)
 			if err != nil {
 				fmt.Fprintf(os.Stderr, "%-30s | Error: %v\n", store.Address, err)
 			} else {
@@ -231,7 +234,7 @@ func checkpointErrorDestroy(ctx context.Context, cfg *config.Config, tls *common
 	}
 
 	if cfg.TikvImporter.Backend == "importer" {
-		importer, err := kv.NewImporter(ctx, tls, cfg.TikvImporter.Addr, cfg.TiDB.PdAddr)
+		importer, err := importer.NewImporter(ctx, tls, cfg.TikvImporter.Addr, cfg.TiDB.PdAddr)
 		if err != nil {
 			return errors.Trace(err)
 		}
@@ -259,8 +262,8 @@ func checkpointErrorDestroy(ctx context.Context, cfg *config.Config, tls *common
 		for _, table := range targetTables {
 			for engineID := table.MinEngineID; engineID <= table.MaxEngineID; engineID++ {
 				fmt.Fprintln(os.Stderr, "Closing and cleaning up engine:", table.TableName, engineID)
-				_, eID := kv.MakeUUID(table.TableName, engineID)
-				file := kv.LocalFile{Uuid: eID}
+				_, eID := backend.MakeUUID(table.TableName, engineID)
+				file := local.File{Uuid: eID}
 				err := file.Cleanup(cfg.TikvImporter.SortedKVDir)
 				if err != nil {
 					fmt.Fprintln(os.Stderr, "* Encountered error while cleanup engine:", err)
@@ -357,7 +360,7 @@ func getLocalStoringTables(ctx context.Context, cfg *config.Config) (err2 error)
 	return nil
 }
 
-func unsafeCloseEngine(ctx context.Context, importer kv.Backend, engine string) (*kv.ClosedEngine, error) {
+func unsafeCloseEngine(ctx context.Context, importer backend.Backend, engine string) (*backend.ClosedEngine, error) {
 	if index := strings.LastIndexByte(engine, ':'); index >= 0 {
 		tableName := engine[:index]
 		engineID, err := strconv.Atoi(engine[index+1:])
@@ -378,7 +381,7 @@ func unsafeCloseEngine(ctx context.Context, importer kv.Backend, engine string)
 }
 
 func importEngine(ctx context.Context, cfg *config.Config, tls *common.TLS, engine string) error {
-	importer, err := kv.NewImporter(ctx, tls, cfg.TikvImporter.Addr, cfg.TiDB.PdAddr)
+	importer, err := importer.NewImporter(ctx, tls, cfg.TikvImporter.Addr, cfg.TiDB.PdAddr)
 	if err != nil {
 		return errors.Trace(err)
 	}
@@ -392,7 +395,7 @@ func importEngine(ctx context.Context, cfg *config.Config, tls *common.TLS, engi
 }
 
 func cleanupEngine(ctx context.Context, cfg *config.Config, tls *common.TLS, engine string) error {
-	importer, err := kv.NewImporter(ctx, tls, cfg.TikvImporter.Addr, cfg.TiDB.PdAddr)
+	importer, err := importer.NewImporter(ctx, tls, cfg.TikvImporter.Addr, cfg.TiDB.PdAddr)
 	if err != nil {
 		return errors.Trace(err)
 	}

pkg/lightning/backend/backend.go

@@ -24,17 +24,16 @@ import (
 	"github.com/pingcap/failpoint"
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/tidb/table"
-	"github.com/pingcap/tidb/types"
 	"go.uber.org/zap"
 
+	"github.com/pingcap/br/pkg/lightning/backend/kv"
 	"github.com/pingcap/br/pkg/lightning/common"
 	"github.com/pingcap/br/pkg/lightning/log"
 	"github.com/pingcap/br/pkg/lightning/metric"
-	"github.com/pingcap/br/pkg/lightning/verification"
 )
 
 const (
-	maxRetryTimes = 3 // tikv-importer has done retry internally. so we don't retry many times.
+	importMaxRetryTimes = 3 // tikv-importer has done retry internally. so we don't retry many times.
 )
 
 /*
@@ -102,7 +101,7 @@ type AbstractBackend interface {
 	Close()
 
 	// MakeEmptyRows creates an empty collection of encoded rows.
-	MakeEmptyRows() Rows
+	MakeEmptyRows() kv.Rows
 
 	// RetryImportDelay returns the duration to sleep when retrying an import
 	RetryImportDelay() time.Duration
@@ -112,7 +111,7 @@ type AbstractBackend interface {
 	ShouldPostProcess() bool
 
 	// NewEncoder creates an encoder of a TiDB table.
-	NewEncoder(tbl table.Table, options *SessionOptions) (Encoder, error)
+	NewEncoder(tbl table.Table, options *kv.SessionOptions) (kv.Encoder, error)
 
 	OpenEngine(ctx context.Context, engineUUID uuid.UUID) error
 
@@ -165,15 +164,6 @@ type AbstractBackend interface {
 	LocalWriter(ctx context.Context, engineUUID uuid.UUID) (EngineWriter, error)
 }
 
-func fetchRemoteTableModelsFromTLS(ctx context.Context, tls *common.TLS, schema string) ([]*model.TableInfo, error) {
-	var tables []*model.TableInfo
-	err := tls.GetJSON(ctx, "/schema/"+schema, &tables)
-	if err != nil {
-		return nil, errors.Annotatef(err, "cannot read schema '%s' from remote", schema)
-	}
-	return tables, nil
-}
-
 // Backend is the delivery target for Lightning
 type Backend struct {
 	abstract AbstractBackend
@@ -221,11 +211,11 @@ func (be Backend) Close() {
 	be.abstract.Close()
 }
 
-func (be Backend) MakeEmptyRows() Rows {
+func (be Backend) MakeEmptyRows() kv.Rows {
 	return be.abstract.MakeEmptyRows()
 }
 
-func (be Backend) NewEncoder(tbl table.Table, options *SessionOptions) (Encoder, error) {
+func (be Backend) NewEncoder(tbl table.Table, options *kv.SessionOptions) (kv.Encoder, error) {
 	return be.abstract.NewEncoder(tbl, options)
 }
 
@@ -353,7 +343,7 @@ func (engine *OpenedEngine) LocalWriter(ctx context.Context) (*LocalEngineWriter
 }
 
 // WriteRows writes a collection of encoded rows into the engine.
-func (w *LocalEngineWriter) WriteRows(ctx context.Context, columnNames []string, rows Rows) error {
+func (w *LocalEngineWriter) WriteRows(ctx context.Context, columnNames []string, rows kv.Rows) error {
 	return w.writer.AppendRows(ctx, w.tableName, columnNames, w.ts, rows)
 }
 
@@ -398,7 +388,7 @@ func (en engine) unsafeClose(ctx context.Context) (*ClosedEngine, error) {
 func (engine *ClosedEngine) Import(ctx context.Context) error {
 	var err error
 
-	for i := 0; i < maxRetryTimes; i++ {
+	for i := 0; i < importMaxRetryTimes; i++ {
 		task := engine.logger.With(zap.Int("retryCnt", i)).Begin(zap.InfoLevel, "import")
 		err = engine.backend.ImportEngine(ctx, engine.uuid)
 		if !common.IsRetryableError(err) {
@@ -409,7 +399,7 @@ func (engine *ClosedEngine) Import(ctx context.Context) error {
 		time.Sleep(engine.backend.RetryImportDelay())
 	}
 
-	return errors.Annotatef(err, "[%s] import reach max retry %d and still failed", engine.uuid, maxRetryTimes)
+	return errors.Annotatef(err, "[%s] import reach max retry %d and still failed", engine.uuid, importMaxRetryTimes)
 }
 
 // Cleanup deletes the intermediate data from target.
@@ -424,53 +414,13 @@ func (engine *ClosedEngine) Logger() log.Logger {
 	return engine.logger
 }
 
-// Encoder encodes a row of SQL values into some opaque type which can be
-// consumed by OpenEngine.WriteEncoded.
-type Encoder interface {
-	// Close the encoder.
-	Close()
-
-	// Encode encodes a row of SQL values into a backend-friendly format.
-	Encode(
-		logger log.Logger,
-		row []types.Datum,
-		rowID int64,
-		columnPermutation []int,
-	) (Row, error)
-}
-
-// Row represents a single encoded row.
-type Row interface {
-	// ClassifyAndAppend separates the data-like and index-like parts of the
-	// encoded row, and appends these parts into the existing buffers and
-	// checksums.
-	ClassifyAndAppend(
-		data *Rows,
-		dataChecksum *verification.KVChecksum,
-		indices *Rows,
-		indexChecksum *verification.KVChecksum,
-	)
-}
-
-// Rows represents a collection of encoded rows.
-type Rows interface {
-	// SplitIntoChunks splits the rows into multiple consecutive parts, each
-	// part having total byte size less than `splitSize`. The meaning of "byte
-	// size" should be consistent with the value used in `Row.ClassifyAndAppend`.
-	SplitIntoChunks(splitSize int) []Rows
-
-	// Clear returns a new collection with empty content. It may share the
-	// capacity with the current instance. The typical usage is `x = x.Clear()`.
-	Clear() Rows
-}
-
 type EngineWriter interface {
 	AppendRows(
 		ctx context.Context,
 		tableName string,
 		columnNames []string,
 		commitTS uint64,
-		rows Rows,
+		rows kv.Rows,
 	) error
 	Close() error
 }

pkg/lightning/backend/backend_test.go

@@ -2,6 +2,7 @@ package backend_test
 
 import (
 	"context"
+	"testing"
 	"time"
 
 	"github.com/golang/mock/gomock"
@@ -11,26 +12,31 @@ import (
 	"github.com/pingcap/parser/mysql"
 	"github.com/pingcap/tidb/store/tikv/oracle"
 
-	kv "github.com/pingcap/br/pkg/lightning/backend"
+	"github.com/pingcap/br/pkg/lightning/backend"
+	"github.com/pingcap/br/pkg/lightning/backend/kv"
 	"github.com/pingcap/br/pkg/mock"
 )
 
 type backendSuite struct {
 	controller  *gomock.Controller
 	mockBackend *mock.MockBackend
-	backend     kv.Backend
+	backend     backend.Backend
 	ts          uint64
 }
 
 var _ = Suite(&backendSuite{})
 
+func Test(t *testing.T) {
+	TestingT(t)
+}
+
 // FIXME: Cannot use the real SetUpTest/TearDownTest to set up the mock
 // otherwise the mock error will be ignored.
 
 func (s *backendSuite) setUpTest(c *C) {
 	s.controller = gomock.NewController(c)
 	s.mockBackend = mock.NewMockBackend(s.controller)
-	s.backend = kv.MakeBackend(s.mockBackend)
+	s.backend = backend.MakeBackend(s.mockBackend)
 	s.ts = oracle.ComposeTS(time.Now().Unix()*1000, 0)
 }
 
@@ -334,7 +340,7 @@ func (s *backendSuite) TestCheckDiskQuota(c *C) {
 	uuid7 := uuid.MustParse("77777777-7777-7777-7777-777777777777")
 	uuid9 := uuid.MustParse("99999999-9999-9999-9999-999999999999")
 
-	fileSizes := []kv.EngineFileSize{
+	fileSizes := []backend.EngineFileSize{
 		{
 			UUID:        uuid1,
 			DiskSize:    1000,