RATIS-2347. NPE in GrpcServerProtocolService. (#1304)

Author: szetszwo

ratis-common/src/main/java/org/apache/ratis/util/ProtoUtils.java

@@ -35,6 +35,8 @@
 import org.apache.ratis.protocol.RaftPeer;
 import org.apache.ratis.protocol.RaftPeerId;
 import org.apache.ratis.thirdparty.com.google.protobuf.ByteString;
+import org.apache.ratis.thirdparty.com.google.protobuf.MessageOrBuilder;
+import org.apache.ratis.thirdparty.com.google.protobuf.TextFormat;
 
 import java.io.IOException;
 import java.io.ObjectOutputStream;
@@ -250,4 +252,8 @@ static String toString(RaftRpcReplyProto proto) {
         + "#" + proto.getCallId() + ":"
         + (proto.getSuccess()? "OK": "FAIL");
   }
+
+  static <MESSAGE extends MessageOrBuilder> String shortDebugString(MESSAGE message) {
+    return message != null ? TextFormat.shortDebugString(message) : "null";
+  }
 }

ratis-grpc/src/main/java/org/apache/ratis/grpc/server/GrpcServerProtocolService.java

@@ -25,7 +25,6 @@
 import org.apache.ratis.server.protocol.RaftServerProtocol;
 import org.apache.ratis.server.util.ServerStringUtils;
 import org.apache.ratis.thirdparty.com.google.protobuf.MessageOrBuilder;
-import org.apache.ratis.thirdparty.com.google.protobuf.TextFormat;
 import org.apache.ratis.thirdparty.io.grpc.Status;
 import org.apache.ratis.thirdparty.io.grpc.StatusRuntimeException;
 import org.apache.ratis.thirdparty.io.grpc.stub.StreamObserver;
@@ -176,7 +175,7 @@ public void onCompleted() {
         requestFuture.get().thenAccept(reply -> {
           BatchLogger.print(BatchLogKey.COMPLETED_REPLY, getName(),
               suffix -> LOG.info("{}: Completed {}, lastReply: {} {}",
-                  getId(), op, TextFormat.shortDebugString(reply), suffix));
+                  getId(), op, ProtoUtils.shortDebugString(reply), suffix));
           responseObserver.onCompleted();
         });
       }

ratis-server/src/main/java/org/apache/ratis/server/impl/SnapshotInstallationHandler.java

@@ -36,7 +36,6 @@
 import org.apache.ratis.server.protocol.TermIndex;
 import org.apache.ratis.server.raftlog.LogProtoUtils;
 import org.apache.ratis.server.util.ServerStringUtils;
-import org.apache.ratis.thirdparty.com.google.protobuf.TextFormat;
 import org.apache.ratis.util.BatchLogger;
 import org.apache.ratis.util.CodeInjectionForTesting;
 import org.apache.ratis.util.LifeCycle;
@@ -145,7 +144,7 @@ private InstallSnapshotReplyProto installSnapshotImpl(InstallSnapshotRequestProt
         final LogEntryProto proto = request.getLastRaftConfigurationLogEntryProto();
         state.truncate(proto.getIndex());
         if (!state.getRaftConf().equals(LogProtoUtils.toRaftConfiguration(proto))) {
-          LOG.info("{}: set new configuration {} from snapshot", getMemberId(), TextFormat.shortDebugString(proto));
+          LOG.info("{}: set new configuration {} from snapshot", getMemberId(), ProtoUtils.shortDebugString(proto));
           state.setRaftConf(proto);
           state.writeRaftConfiguration(proto);
           server.getStateMachine().event().notifyConfigurationChanged(