Janusgraph: Please support cypher for gremlin

[bionicles]

For discussion on internal implementation details of JanusGraph or proposing a major new feature or subproject use the janusgraph-dev.

Describe the feature:
If JanusGraph added this plugin https://github.com/opencypher/cypher-for-gremlin/tree/master/tinkerpop/cypher-gremlin-server-plugin it may be possible to support cypher query language relatively easily. If the storage were serverless (like a managed cassandra service) and the janusgraph were containerized and run on serverless container service (like fargate or cloud run) then we could have 100% serverless autoscaling graphs with both cypher and gremlin. If this were infrastructure as code ready with ex: terraform or pulumi or cdk or cfn, the whole stack could be launched with a few termina l commands. And you'd pay nothing if you weren't using it, because it'd be serverless. That sounds like a major win, but i'm not familiar with the codebase... can you please help me add cypher and infrastructure as code?

Describe a specific use case for the feature:
startups or prototypes can copy a terraform template and with a couple commands launch a serverless graph with cypher and gremlin

[FlorianHockmann]

You can simply add this plugin on your own so I don't see why JanusGraph should preinstall this for all users if only some of them are interested in Cypher. We could maybe add a short section to the docs that describe this.

[bionicles]

I would definitely be down to read and use those docs and I could make the infrastructure as code part. My concern is simply I’m not sure how to install the plugin in the dockerfile and not sure how to switch the storage engine to Cassandra (though there’s a nice docker-compose for this)

[FlorianHockmann]

How a dependency can be installed in general is explained in the TinkerPop docs for the Gremlin Server which JanusGraph just extends.
As the docs mention, this commands just grabs the JAR and puts it into the ext directory. So, you can also do that manually in your Dockerfile instead. But I see that you already created JanusGraph/janusgraph-docker#49 to document this for our Docker image.

[FlorianHockmann]

Closing this as it's a duplicate of #161.