Gremlin-Python: Returning a fully populated subgraph

[Terell Brown]

As the topic describes I am using the Gremlin-Python Client to query Gremlin Server with a neo4j backend. 

Running the following query:

graph = Graph()
g = graph.traversal().withRemote(DriverRemoteConnection('ws://localhost:8182/gremlin','g'))
sg = g.E().subgraph('a').cap('a').next()

returns a subgraph containing a list of edges and vertices. 

The problem is the vertices only contain their associated id and label. The vertex properties are missing.

Here's what I want:

{ "@type": "g:Vertex", "@value": { "id": { "@type": "g:Int32", "@value": 1 }, "label": "person", "properties": { "name": [{ "@type": "g:VertexProperty", "@value": { "id": { "@type": "g:Int64", "@value": 0 }, "value": "marko", "label": "name" } }], "uuid": [{ "@type": "g:VertexProperty", "@value": { "id": { "@type": "g:Int64", "@value": 12 }, "value": { "@type": "g:UUID", "@value": "829c7ddb-3831-4687-a872-e25201230cd3" }, "label": "uuid" } }]

}

Here's what I get:

{ "@type": "g:Vertex", "@value": { "id": { "@type": "g:Int32", "@value": 1 }, "label": "person" }

I've also already configured Gremlin Server to support returning TinkerGraph responses:

serializers:
 - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoMessageSerializerV1d0, config: { useMapperFromGraph: graph }} # application/vnd.gremlin-v1.0+gryo
 - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoLiteMessageSerializerV1d0, config: { useMapperFromGraph: graph }} # application/vnd.gremlin-v1.0+gryo-lite
 - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoMessageSerializerV1d0, config: { serializeResultToString: true }} # application/vnd.gremlin-v1.0+gryo-stringd
 - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerGremlinV1d0, config: { useMapperFromGraph: graph }} # application/vnd.gremlin-v1.0+json
 - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerGremlinV2d0, config: { ioRegistries: [org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerIoRegistryV2d0] }} # application/vnd.gremlin-v2.0+json
 - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerV3d0, config: { ioRegistries: [org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerIoRegistryV3d0] }} # application/vnd.gremlin-v3.0+json


 - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerV1d0, config: { useMapperFromGraph: graph }} # application/json

Does anyone know how to configure gremlin-server to return a fully populated subgraph?

[Marko Rodriguez]

Hi,

Gremlin-Python’s GraphSON serializers currently don’t support full “detachment.” This is something that we will be addressing in TinkerPop 3.3.0 as we redesign our “element detachment framework” to better accommodate the numerous stakeholders:

1. Gremlin language variants (like Gremlin-Python)

2. OLAP GraphComputers (like SparkGraphComputer)

3. OLAP GraphActors (like AkkaGraphActors)

4. RemoteConnection servers (like GremlinServer)

5. …

Marko.

http://markorodriguez.com

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[Marko Rodriguez]

Hi,

1. Do you have a timeline for when TinkerPop 3.3.0 will be available? 

I don’t think there is a set date. I suspect (though I don’t know) probably around mid-Spring.

2. Also is there anywhere that I can keep up with the progress of this feature implementation?

https://issues.apache.org/jira/browse/TINKERPOP-1592

https://issues.apache.org/jira/browse/TINKERPOP-1474

https://issues.apache.org/jira/browse/TINKERPOP-1311

3. Lastly, I'd like to further understand the issue hear:

We sort of threw together our “detachment framework.” What is detachment? Any element in the graph (a vertex, edge, or vertex property) can be “detached” as an isolated, un-traversable object. Moreover, it can later be re-attached. This is means by which element data is serialized to various systems. Now, its not so simple as having one type of detachment. For OLAP systems (GraphComputer/GraphActors) you only want to message pass the smallest amount of information necessary to re-attach the element at the respective partition in the cluster. For this, we have ReferenceXXX — ReferenceVertex simply has the vertex ID and label. For GUI applications, they typically want a vertex and all of its properties. For this, there is DetachedXXX.

We have realized, that there is a continum of requirements for detachment and thus, we need to not only come up with a suite of “detachment” scenarios, we also need to define a way for users/systems to specify how they want their elements to be both attached and re-attached.

Our redesign will require lots of internal refactoring and deprecation and thus, will be slated for TinkerPop 3.3.0.

HTH,

Marko.

http://markorodriguez.com

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[Terell Brown]

Great explanation. Thanks Marko!

[Moses Ebenezer Christopher]

Hi Marko,

Would you have some example sample code of how a subgraph data can be gathered using gremlinpython?

Many thanks,

Moses

[Stephen Mallette]

Answered here:

https://stackoverflow.com/q/54045859/1831717

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