br: add more retryable error for br_import (#48529) (#48544)

close #48528

br/pkg/utils/backoff.go

@@ -140,6 +140,7 @@ func NewDownloadSSTBackoffer() Backoffer {
 }
 
 func (bo *importerBackoffer) NextBackoff(err error) time.Duration {
+	log.Warn("retry to import ssts", zap.Int("attempt", bo.attempt), zap.Error(err))
 	if MessageIsRetryableStorageError(err.Error()) {
 		bo.delayTime = 2 * bo.delayTime
 		bo.attempt--

br/pkg/utils/retry.go

@@ -30,6 +30,7 @@ var retryableServerError = []string{
 	"not read from or written to within the timeout period",
 	"<code>requesttimeout</code>",
 	"<code>invalidpart</code>",
+	"end of file before message length reached",
 }
 
 // RetryableFunc presents a retryable operation.

br/tests/br_full/run.sh

@@ -53,7 +53,7 @@ test_log="${TEST_DIR}/${DB}_test.log"
 error_str="not read from or written to within the timeout period"
 unset BR_LOG_TO_TERM
 
-export GO_FAILPOINTS="github.com/pingcap/tidb/br/pkg/backup/backup-storage-error=1*return(\"connection refused\")->1*return(\"InternalError\");github.com/pingcap/tidb/br/pkg/backup/backup-timeout-error=1*return(\"<Code>RequestTimeout</Code>\")->1*return(\"not read from or written to within the timeout period\")->1*return(\"<Code>InvalidPart</Code>\")"
+export GO_FAILPOINTS="github.com/pingcap/tidb/br/pkg/backup/backup-storage-error=1*return(\"connection refused\")->1*return(\"InternalError\");github.com/pingcap/tidb/br/pkg/backup/backup-timeout-error=1*return(\"<Code>RequestTimeout</Code>\")->1*return(\"not read from or written to within the timeout period\")->1*return(\"<Code>InvalidPart</Code>\")->1*return(\"end of file before message length reached\")"
 run_br --pd $PD_ADDR backup full -s "local://$TEST_DIR/$DB-lz4" --concurrency 4 --compression lz4 --log-file $test_log
 export GO_FAILPOINTS=""
 size_lz4=$(du -d 0 $TEST_DIR/$DB-lz4 | awk '{print $1}')