feat(storagenode): add empty payload validation

Add validation for empty payloads in the Append RPC. If there is no payload
in the append request, the RPC returns a gRPC status code of InvalidArgument.

Author: ijsong

internal/storagenode/log_server.go

@@ -103,6 +103,11 @@ func (ls *logServer) appendStreamRecvLoop(stream snpb.LogIO_AppendServer, cq cha
 			goto Out
 		}
 
+		if len(req.Payload) == 0 {
+			err = status.Error(codes.InvalidArgument, "no payload")
+			goto Out
+		}
+
 		if tpid.Invalid() && lsid.Invalid() {
 			err = snpb.ValidateTopicLogStream(req)
 			if err != nil {

internal/storagenode/storagenode_test.go

@@ -458,6 +458,14 @@ func TestStorageNode_Append(t *testing.T) {
 		name  string
 		testf func(t *testing.T, addr string, lc *client.LogClient)
 	}{
+		{
+			name: "NoPayload",
+			testf: func(t *testing.T, addr string, lc *client.LogClient) {
+				_, err := lc.Append(context.Background(), tpid, lsid, nil)
+				require.Error(t, err)
+				require.Equal(t, codes.InvalidArgument, status.Code(err))
+			},
+		},
 		{
 			name: "InvalidTopicID",
 			testf: func(t *testing.T, _ string, lc *client.LogClient) {

proto/snpb/log_io.pb.go

@@ -184,18 +184,18 @@ service LogIO {
   // is, some of the log entries could not be stored due to failures.
   //
   // It returns the following gRPC errors:
-  // - InvalidArgument: AppendRequest has invalid fields; for instance, TopicID
-  // is invalid.
-  // - NotFound: The log stream replica specified by the AppendRequest does not
-  // exist in the storage node. Note that it does not mean that the log stream
-  // does not exist in the cluster.
-  // - FailedPrecondition: The log stream may be sealed; thus, clients cannot
-  // write the log entry. Clients should unseal the log stream to append a log
-  // entry to the log stream.
-  // - Unavailable: The storage node is shutting down, or the log stream replica
-  // is not primary.
-  // - Canceled: The client canceled the request.
-  // - DeadlineExceeded: The client's timeout has expired.
+  //   - InvalidArgument: AppendRequest has invalid fields; for instance,
+  //   TopicID or LogStreamID is invalid, or there is no payload.
+  //   - NotFound: The log stream replica specified by the AppendRequest does
+  //   not exist in the storage node. Note that it does not mean that the log
+  //   stream does not exist in the cluster.
+  //   - FailedPrecondition: The log stream may be sealed; thus, clients cannot
+  //   write the log entry. Clients should unseal the log stream to append a log
+  //   entry to the log stream.
+  //   - Unavailable: The storage node is shutting down, or the log stream
+  //   replica is not primary.
+  //   - Canceled: The client canceled the request.
+  //   - DeadlineExceeded: The client's timeout has expired.
   //
   // FIXME: Partial failures are not specified by the gRPC error codes.
   rpc Append(stream AppendRequest) returns (stream AppendResponse) {}