Running with Cosmos DB emulator

[Javaad Patel]

Is there a way to run this using the cosmosdb emulator? Recently the emulator has been updated to support graph. I am getting an error when trying to connect with the below code

            .UseCosmosDb("https://localhost", "test", "testGraph", 
                    "C2y6yDjf5/R+ob0N8A7Cgv30VRDJIWEHLM+4QDU5DE2nQ9nDuVTqobD4b8mGGyPMbIZnqyMsEcaGQy67XIw/Jw==", port: 8901);

[Daniel Weber]

I don't have any experience with the local emulator. I didn't know it now supports graph, that's awesome. If you are sure it's serving on that particular port (you might wanna verify it with the Tinkerpop Gremlin Console), try omitting "https".

[Javaad Patel]

thanks for that hint, I got it connected to the Gremlin console and was able to create a node. This is the microsoft guide to enable graph in the local emulator:
https://docs.microsoft.com/en-us/azure/cosmos-db/local-emulator#gremlin-api

I then put this as my config:

 _g = g
                //Since the Vertex and Edge classes contained in this sample implement IVertex resp. IEdge,
                //setting a model is actually not required as long as these classes are discoverable (i.e. they reside
                //in a currently loaded assembly). We explicitly set a model here anyway.
                .UseModel(GraphModel.FromBaseTypes<Vertex, Edge>())

                //Configure Gremlinq to work on a locally running instance of Gremlin server.
                //.UseWebSocket("localhost", GraphsonVersion.V3)

                //For Gremlin Server >= 3.4.0, we need to remove all ReferenceElementStrategies
                //from the traversals, or else we don't get any vertex properties in the returned
                //json-payloads and we end up with NullReferenceExceptions. Uncomment below
                //when running on Gremlin Server >= 3.4.0.
                //.RemoveStrategies("ReferenceElementStrategy")

                //Uncomment below, comment above and enter appropriate data to configure Gremlinq to work on CosmosDB!
                .UseCosmosDb(
                    hostname: "localhost",
                    database: "db1",
                    graphName: "coll1",
                    authKey: "C2y6yDjf5/R+ob0N8A7Cgv30VRDJIWEHLM+4QDU5DE2nQ9nDuVTqobD4b8mGGyPMbIZnqyMsEcaGQy67XIw/Jw==",
                    port: 8901
                );

I get an error saying can't do the SSL handshake,

but I don't know where to specify to disable SSL, from the settings I don't think the local emulator supports SSL based on this line in the .yaml file:

connectionPool: {enableSsl: false}

[Javaad Patel]

Okay, i changed the config to rather use UseWebSocket like this:

                //Configure Gremlinq to work on a locally running instance of Gremlin server.
                .UseWebSocket(
                    hostname: "localhost",
                    graphsonVersion: GraphsonVersion.V2, 
                    port: 8901,
                    username: "/dbs/db1/colls/coll1",
                    password: "C2y6yDjf5/R+ob0N8A7Cgv30VRDJIWEHLM+4QDU5DE2nQ9nDuVTqobD4b8mGGyPMbIZnqyMsEcaGQy67XIw/Jw==");

, it seems the local emulator doesn't support GraphsonVersion.V3 because setting it to V3 gave this error:

but after changing to v2, now i get this error:

I see from the .yaml file that emulator sets up that it specifies a serializer:

serializer: { 
    className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerV1d0,
    config: { 
             serializeResultToString: true  
    }
}

and I see UseWebSocket has a parameter to pass in an additional serializer, not sure if this could be something that I need to set.

[Daniel Weber]

Alright, so the local emulator apparently doesn't use SSL. What's the package version of ExRam.Gremlinq you're using?

[Javaad Patel]

I am using one of the awesome samples you have provided, the version in your sample project is v7.0.0-preview-0126

[Daniel Weber]

Have a look at the UseCosmosDB extension method here. Copy the whole file into your project, set useSSL to false. If it works, and you don't mind, you could maybe provide a PR for a potential "UseCosmosDBEmulator" extension...

[Javaad Patel]

amazing! it is working :)

I would be happy to make a PR, I can either add a UseCosmosDBEmulator or just open up the setting ssl like this :

public static IConfigurableGremlinQuerySource UseCosmosDb(this IConfigurableGremlinQuerySource source, string hostname, string database, string graphName, string authKey, bool enableSSL = false, int port = 443)

on UseCosmosDb which would you prefer? And if you don't mind I can make an update to the readme to say how to setup the emulator?

[Daniel Weber]

UseCosmosDBEmulator would be just fine. An update to the readme (or the samples) would be awesome.

[Javaad Patel]

i've made the PR, i've never contributed to someone else's repository before, so I hope that I have done this correctly and you can see it.

Also, I couldn't update the sample project because when I cloned the repo, the samples wouldn't load

this is in VS 2019.

[Daniel Weber]

When cloned, you need to init your git submodules because the samples are from another repo:

git submodule init
git submodule update

[Daniel Weber]

Fixed by #24.