咨询：Cosmos DB是否支持Gremlin.net C# GLV？求远程使用示例

Absolutely! Azure Cosmos DB does support the Gremlin.NET C# GLV (Gremlin Language Variant) — it’s one of the officially recommended methods for interacting with its graph databases from C#. Let me break down how to set this up with a working code example, since documentation can be scattered at times.

Step 1: Install the Gremlin.NET package #

First, add the Gremlin.NET NuGet package to your project. You can do this via the Package Manager Console:

Install-Package Gremlin.Net

Or using the .NET CLI:

dotnet add package Gremlin.Net

Step 2: Connect to Cosmos DB Graph and run queries #

Here’s a complete code snippet that initializes a connection, adds a vertex, and runs a sample query:

using Gremlin.Net.Driver;
using Gremlin.Net.Driver.Remote;
using Gremlin.Net.Structure.IO.GraphSON;
using static Gremlin.Net.Process.Traversal.AnonymousTraversalSource;

// Replace these values with your Cosmos DB details
var cosmosDbEndpoint = "your-cosmosdb-account.gremlin.cosmos.azure.com";
var cosmosDbPrimaryKey = "your-account-primary-key";
var databaseName = "your-target-database";
var graphContainerName = "your-graph-container";

// Configure client settings - critical for Cosmos DB compatibility
var clientSettings = new GremlinClientSettings
{
    // Use WebSocket protocol (required for Cosmos DB)
    Endpoint = new Uri($"wss://{cosmosDbEndpoint}:443/"),
    // Authenticate with your Cosmos DB primary key
    Credentials = new GremlinServerCredentials(cosmosDbPrimaryKey),
    // Cosmos DB uses GraphSON 2.0 - do NOT use GraphSON 3.0
    Serializer = new GraphSON2MessageSerializer(),
    // Optional: Adjust connection pool settings based on your workload
    ConnectionPoolSettings = new ConnectionPoolSettings
    {
        PoolSize = 3,
        ReconnectionAttempts = 3
    }
};

// Initialize the Gremlin client
using var gremlinClient = new GremlinClient(clientSettings);

// Create a remote traversal source tied to your database and graph container
var g = Traversal().WithRemote(new DriverRemoteConnection(
    gremlinClient, 
    $"/dbs/{databaseName}/colls/{graphContainerName}"
));

// Example 1: Add a new vertex
var newUserVertex = g.AddV("user")
                     .Property("username", "johndoe")
                     .Property("email", "john@example.com")
                     .Next();
Console.WriteLine($"Added vertex with ID: {newUserVertex.Id}");

// Example 2: Query all user vertices
var allUsers = g.V().HasLabel("user")
                  .Values<string>("username")
                  .ToList();
foreach (var username in allUsers)
{
    Console.WriteLine($"Found user: {username}");
}

Key Notes to Avoid Issues #

• GraphSON Version: Cosmos DB only supports GraphSON 2.0, so make sure you use GraphSON2MessageSerializer (not the newer GraphSON 3.0 serializers).
• Endpoint Format: Always use the wss:// protocol (WebSocket) for the endpoint — HTTP won’t work for Gremlin connections.
• Firewall Settings: Ensure your Cosmos DB account’s firewall allows incoming connections from your client’s IP address.
• Resource Path: The remote connection path must follow the format /dbs/{databaseName}/colls/{graphContainerName} to target the correct graph.

If you run into authentication errors, double-check that your primary key is copied correctly (it’s easy to miss a character!). Also, verify that your graph container was created with the "Graph" API type in the Azure portal.

内容的提问来源于stack exchange，提问作者cmant