br: add more retry strategy: s3.ReadFile: body reader (#50541) (#50706)

close #49942

br/pkg/storage/s3.go

@@ -515,22 +515,41 @@ func (rs *S3Storage) WriteFile(ctx context.Context, file string, data []byte) er
 
 // ReadFile reads the file from the storage and returns the contents.
 func (rs *S3Storage) ReadFile(ctx context.Context, file string) ([]byte, error) {
-	input := &s3.GetObjectInput{
-		Bucket: aws.String(rs.options.Bucket),
-		Key:    aws.String(rs.options.Prefix + file),
-	}
-	result, err := rs.svc.GetObjectWithContext(ctx, input)
-	if err != nil {
-		return nil, errors.Annotatef(err,
-			"failed to read s3 file, file info: input.bucket='%s', input.key='%s'",
-			*input.Bucket, *input.Key)
-	}
-	defer result.Body.Close()
-	data, err := io.ReadAll(result.Body)
-	if err != nil {
-		return nil, errors.Trace(err)
+	var (
+		data    []byte
+		readErr error
+	)
+	for retryCnt := 0; retryCnt < maxErrorRetries; retryCnt += 1 {
+		input := &s3.GetObjectInput{
+			Bucket: aws.String(rs.options.Bucket),
+			Key:    aws.String(rs.options.Prefix + file),
+		}
+		result, err := rs.svc.GetObjectWithContext(ctx, input)
+		if err != nil {
+			return nil, errors.Annotatef(err,
+				"failed to read s3 file, file info: input.bucket='%s', input.key='%s'",
+				*input.Bucket, *input.Key)
+		}
+		data, readErr = io.ReadAll(result.Body)
+		// close the body of response since data has been already read out
+		result.Body.Close()
+		// for unit test
+		failpoint.Inject("read-s3-body-failed", func(_ failpoint.Value) {
+			log.Info("original error", zap.Error(readErr))
+			readErr = errors.Errorf("read: connection reset by peer")
+		})
+		if readErr != nil {
+			if isDeadlineExceedError(readErr) || isCancelError(readErr) {
+				return nil, errors.Annotatef(readErr, "failed to read body from get object result, file info: input.bucket='%s', input.key='%s', retryCnt='%d'",
+					*input.Bucket, *input.Key, retryCnt)
+			}
+			continue
+		}
+		return data, nil
 	}
-	return data, nil
+	// retry too much, should be failed
+	return nil, errors.Annotatef(readErr, "failed to read body from get object result (retry too much), file info: input.bucket='%s', input.key='%s'",
+		rs.options.Bucket, rs.options.Prefix+file)
 }
 
 // DeleteFile delete the file in s3 storage
@@ -989,6 +1008,10 @@ type retryerWithLog struct {
 	client.DefaultRetryer
 }
 
+func isCancelError(err error) bool {
+	return strings.Contains(err.Error(), "context canceled")
+}
+
 func isDeadlineExceedError(err error) bool {
 	// TODO find a better way.
 	// Known challenges:

br/pkg/storage/s3_test.go

@@ -12,6 +12,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"strings"
 	"sync"
 	"testing"
 
@@ -1343,3 +1344,40 @@ func TestRetryError(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, count, int32(2))
 }
+
+func TestS3ReadFileRetryable(t *testing.T) {
+	s := createS3Suite(t)
+	ctx := aws.BackgroundContext()
+	errMsg := "just some unrelated error"
+	expectedErr := errors.New(errMsg)
+
+	s.s3.EXPECT().
+		GetObjectWithContext(ctx, gomock.Any()).
+		DoAndReturn(func(_ context.Context, input *s3.GetObjectInput, opt ...request.Option) (*s3.GetObjectOutput, error) {
+			require.Equal(t, "bucket", aws.StringValue(input.Bucket))
+			require.Equal(t, "prefix/file", aws.StringValue(input.Key))
+			return &s3.GetObjectOutput{
+				Body: io.NopCloser(bytes.NewReader([]byte("test"))),
+			}, nil
+		})
+	s.s3.EXPECT().
+		GetObjectWithContext(ctx, gomock.Any()).
+		DoAndReturn(func(_ context.Context, input *s3.GetObjectInput, opt ...request.Option) (*s3.GetObjectOutput, error) {
+			require.Equal(t, "bucket", aws.StringValue(input.Bucket))
+			require.Equal(t, "prefix/file", aws.StringValue(input.Key))
+			return &s3.GetObjectOutput{
+				Body: io.NopCloser(bytes.NewReader([]byte("test"))),
+			}, nil
+		})
+	s.s3.EXPECT().
+		GetObjectWithContext(ctx, gomock.Any()).
+		Return(nil, expectedErr)
+
+	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/br/pkg/storage/read-s3-body-failed", "2*return(true)"))
+	defer func() {
+		failpoint.Disable("github.com/pingcap/tidb/br/pkg/storage/read-s3-body-failed")
+	}()
+	_, err := s.storage.ReadFile(ctx, "file")
+	require.Error(t, err)
+	require.True(t, strings.Contains(err.Error(), errMsg))
+}

br/pkg/utils/BUILD.bazel

@@ -89,7 +89,7 @@ go_test(
     ],
     embed = [":utils"],
     flaky = True,
-    shard_count = 33,
+    shard_count = 34,
     deps = [
         "//br/pkg/errors",
         "//br/pkg/metautil",