feat(client): add table and column name length validation

sender.go

@@ -48,6 +48,11 @@ import (
 // chars found in table or column name.
 var ErrInvalidMsg = errors.New("invalid message")
 
+const (
+defaultBufferCapacity = 128 * 1024
+defaultFileNameLimit = 127
+)
+
 type tlsMode int64
 
 const (
@@ -62,18 +67,19 @@ const (
 // Each sender corresponds to a single TCP connection. A sender
 // should not be called concurrently by multiple goroutines.
 type LineSender struct {
-address string
-tlsMode tlsMode
-keyId string // Erased once auth is done.
-key string // Erased once auth is done.
-bufCap int
-conn net.Conn
-buf *buffer
-lastMsgPos int
-lastErr error
-hasTable bool
-hasTags bool
-hasFields bool
+address string
+tlsMode tlsMode
+keyId string // Erased once auth is done.
+key string // Erased once auth is done.
+bufCap int
+fileNameLimit int
+conn net.Conn
+buf *buffer
+lastMsgPos int
+lastErr error
+hasTable bool
+hasTags bool
+hasFields bool
 }
 
 // LineSenderOption defines line sender option.
@@ -126,6 +132,18 @@ func WithBufferCapacity(capacity int) LineSenderOption {
 }
 }
 
+// WithFileNameLimit sets maximum file name length in chars
+// allowed by the server. Affects maximum table and column name
+// lengths accepted by the sender. Should be set to the same value
+// as on the server. Defaults to 127.
+func WithFileNameLimit(limit int) LineSenderOption {
+return func(s *LineSender) {
+if limit > 0 {
+s.fileNameLimit = limit
+}
+}
+}
+
 // NewLineSender creates new InfluxDB Line Protocol (ILP) sender. Each
 // sender corresponds to a single TCP connection. Sender should
 // not be called concurrently by multiple goroutines.
@@ -138,9 +156,10 @@ func NewLineSender(ctx context.Context, opts ...LineSenderOption) (*LineSender,
 )
 
 s := &LineSender{
-address: "127.0.0.1:9009",
-bufCap: 128 * 1024,
-tlsMode: noTls,
+address: "127.0.0.1:9009",
+bufCap: defaultBufferCapacity,
+fileNameLimit: defaultFileNameLimit,
+tlsMode: noTls,
 }
 for _, opt := range opts {
 opt(s)
@@ -375,6 +394,11 @@ func (s *LineSender) writeTableName(str string) error {
 if str == "" {
 return fmt.Errorf("table name cannot be empty: %w", ErrInvalidMsg)
 }
+// We use string length in bytes as an approximation. That's to
+// avoid calculating the number of runes.
+if len(str) > s.fileNameLimit {
+return fmt.Errorf("table name length exceeds the limit: %w", ErrInvalidMsg)
+}
 // Since we're interested in ASCII chars, it's fine to iterate
 // through bytes instead of runes.
 for i := 0; i < len(str); i++ {
@@ -470,6 +494,11 @@ func (s *LineSender) writeColumnName(str string) error {
 if str == "" {
 return fmt.Errorf("column name cannot be empty: %w", ErrInvalidMsg)
 }
+// We use string length in bytes as an approximation. That's to
+// avoid calculating the number of runes.
+if len(str) > s.fileNameLimit {
+return fmt.Errorf("column name length exceeds the limit: %w", ErrInvalidMsg)
+}
 // Since we're interested in ASCII chars, it's fine to iterate
 // through bytes instead of runes.
 for i := 0; i < len(str); i++ {

sender_test.go

@@ -193,6 +193,52 @@ func TestFloat64Serialization(t *testing.T) {
 }
 }
 
+func TestErrorOnLengthyNames(t *testing.T) {
+const nameLimit = 42
+
+var (
+lengthyStr = strings.Repeat("a", nameLimit+1)
+ctx = context.Background()
+)
+
+testCases := []struct {
+name string
+writerFn writerFn
+expectedErrMsg string
+}{
+{
+"lengthy table name",
+func(s *qdb.LineSender) error {
+return s.Table(lengthyStr).StringColumn("str_col", "foo").AtNow(ctx)
+},
+"table name length exceeds the limit",
+},
+{
+"lengthy column name",
+func(s *qdb.LineSender) error {
+return s.Table(testTable).StringColumn(lengthyStr, "foo").AtNow(ctx)
+},
+"column name length exceeds the limit",
+},
+}
+
+for _, tc := range testCases {
+t.Run(tc.name, func(t *testing.T) {
+srv, err := newTestServer(readAndDiscard)
+assert.NoError(t, err)
+
+sender, err := qdb.NewLineSender(ctx, qdb.WithAddress(srv.addr), qdb.WithFileNameLimit(nameLimit))
+assert.NoError(t, err)
+
+err = tc.writerFn(sender)
+assert.ErrorContains(t, err, tc.expectedErrMsg)
+
+sender.Close()
+srv.close()
+})
+}
+}
+
 func TestErrorOnMissingTableCall(t *testing.T) {
 ctx := context.Background()