Remote Graph

About Remote Graph

Gremlin Server allows a JanusGraph instance to run on a standalone server. This enables multiple clients to connect to the same JanusGraph instance. It also allows clients to connect via non-JVM languages. By default, the Gremlin Server communicates over WebSocket.

RemoteGraphApp.java is an example Java program that connects to the Gremlin Server in two ways:

Gremlin Driver client. Sumbit scripts as a String for evaluation on the server.
Remote Graph uses the same client connection but enables you to compose queries as code.

JanusGraph configuration

JanusGraph Server configuration

Select a specific storage backend to use, then copy its configuration into the $JANUSGRAPH_HOME/conf/gremlin-server directory
Update the $JANUSGRAPH_HOME/conf/gremlin-server/gremlin-server.yaml to use the configuration file, for example:
```
graphs: {
    graph: conf/gremlin-server/jgex-cql.properties
}
```
Note the default $JANUSGRAPH_HOME/conf/gremlin-server/gremlin-server.yaml uses the script scripts/empty-graph.groovy to define the graph traversal source g for the graph g: graph.traversal()

JanusGraph pre-packaged distribution

Rather than installing Cassandra and Elasticsearch separately, the JanusGraph pre-packaged distribution is provided for convenience. The distribution starts a local Cassandra, Elasticsearch, and Gremlin Server.

Remote Graph configuration

jgex-remote.properties contains the remote connection class, the Gremlin Driver configuration file location, and the graph traversal source name. Refer to the Remote Graph documentation for additional details.
remote-objects.yaml contains server location and serializer options. The default serializer is Gryo, and it is important that the server is configured with the same serializer. Refer to the Gremlin Driver documentation for additional properties.

Dependencies

The required Maven dependency for remote graph:

        <dependency>
            <groupId>org.apache.tinkerpop</groupId>
            <artifactId>gremlin-driver</artifactId>
            <version>${tinkerpop.version}</version>
        </dependency>

Run the example

Start the JanusGraph Server

Start the JanusGraph Server with the preferred storage configuration. The graph instance will be created if it did not previously exist. Make sure to check the server logs for errors.

$JANUSGRAPH_HOME/bin/janusgraph-server.sh $JANUSGRAPH_HOME/conf/gremlin-server/gremlin-server.yaml

Run the example application

This command can be run from the examples or the project's directory.

mvn exec:java -pl :example-remotegraph

Drop the graph

Make sure to stop the application and the Gremlin Server before dropping the graph. Follow the directions for the specific storage backend.