Serializing JsonNode

[Jeff]

Hi folks, 

I've a gremlin server (JanusGraph) and am trying to add a vertex to a graph in Java code but am facing some serialization errors which I can't understand.

The server serializers are configured like below

serializers:
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphBinaryMessageSerializerV1, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphBinaryMessageSerializerV1, config: { serializeResultToString: true }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoMessageSerializerV3d0, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoMessageSerializerV3d0, config: { serializeResultToString: true }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerV3d0, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}

The code to connect and add a vertex is 

var registry =
      TypeSerializerRegistry.build().addRegistry(JanusGraphIoRegistry.instance()).create();
    var cluster = Cluster.build("localhost").port(8182)
        .serializer(new GraphBinaryMessageSerializerV1(registry)).create();

var json = mapper.valueToTree(obj);

g.addV(LABEL).property(PROPERTY, json).next();

The error i see is

io.netty.handler.codec.EncoderException: org.apache.tinkerpop.gremlin.driver.exception.ResponseException: An error occurred during serialization of this request [REQUEST MESSAGE REDACTED] - it could not be sent to the server - Reason: org.apache.tinkerpop.gremlin.driver.ser.SerializationException: java.io.IOException: Serializer for type org.apache.tinkerpop.shaded.jackson.databind.node.ObjectNode not found
at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:104) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:764) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at io.netty.channel.AbstractChannelHandlerContext$WriteTask.run(AbstractChannelHandlerContext.java:1071) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:469) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]
Caused by: org.apache.tinkerpop.gremlin.driver.exception.ResponseException: An error occurred during serialization of this request [REQUEST MESSAGE REDACTED] - it could not be sent to the server - Reason: org.apache.tinkerpop.gremlin.driver.ser.SerializationException: java.io.IOException: Serializer for type org.apache.tinkerpop.shaded.jackson.databind.node.ObjectNode not found
at org.apache.tinkerpop.gremlin.driver.handler.WebSocketGremlinRequestEncoder.encode(WebSocketGremlinRequestEncoder.java:60) ~[gremlin-driver-3.5.5.jar:3.5.5]
at org.apache.tinkerpop.gremlin.driver.handler.WebSocketGremlinRequestEncoder.encode(WebSocketGremlinRequestEncoder.java:38) ~[gremlin-driver-3.5.5.jar:3.5.5]
at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:89) ~[netty-all-4.1.66.Final.jar:4.1.66.Final]
... 9 common frames omitted

Both server and driver are already using the same serializers and https://docs.janusgraph.org/advanced-topics/serializer/ states that it should be able to deserialize ObjectNodes, so what could be the cause of this? Even using a normal byte[] will fail in code but when the same is done thru the gremlin-console, it does seem to work.

My issue could be worked around by using a JSON string instead of a JSON node but i really want to understand what went wrong or did i misunderstand how serializers work in the system.

Apologies if this is not the right channel but I've asked over at stackoverflow with no answers.

[Stephen Mallette]

A JsonNode is not a supported type for GraphBinary:

https://tinkerpop.apache.org/docs/current/dev/io/#graphbinary

GraphBinary also doesn't do Array exactly which is why i assume byte[] didn't work - it would have to be List<Byte> i guess or a ByteBuffer in Java.

--
You received this message because you are subscribed to the Google Groups "Gremlin-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to gremlin-user...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/gremlin-users/6926adaa-60a6-41ad-994a-b7c09a46af87n%40googlegroups.com.

[Jeff]

Got it! Thanks Stephen!