Migrating Orient Vertex to Cosmos DB using gremlin query

Question

So i have an orient 2.0.0 db , and i want to move this db to cosmos db . The technology i am using is .Net , so i can not use java, and the other richer drivers.

The main problem i am facing during migration is that my orient vertex contain properties that are objects. So is there a way to add objects as property using gremlin query into cosmos db.

The examples on tinkerpop doc , and Azure Cosmos DB Docs for gremlin all show adding simple data types only.

Answer 1

As far as I know, add objects as property is not supported using gremlin query into cosmos db currently.

My workaroud is that we could flat the object. I wrote a test demo, you could add you own logical to it.

The following is my detail steps:

1.Create a C# project and add Microsoft.Azure.Graphs SDK, more detail please refer to packages.config section.

2.Add a custom class to the project

public class Custom
    {
        public string Type { get; set; }
        public string Name { get; set; }
    }

3. Add a function to covert object to Gremlin string

 public static string CovertToGremlinString(object pObject,string type)
        {
            var propertyList = new List<string>();
           // var dic = new Dictionary<string, string>();
            if (pObject == null) return null;
            var jobject = JObject.FromObject(pObject);
            propertyList.AddRange(pObject.GetType().GetProperties().Select(prop => prop.Name));
            var s = propertyList.Aggregate($"g.addV('{type}')", (current, property) => current + $".property('{property}','{jobject[property]})')");
           // dic.Add(type, s);
            return s;
        }

4.Add RunAsync function, we also could get the demo code from Azure portal

public async Task RunAsync(DocumentClient client)
    {
        Database database = await client.CreateDatabaseIfNotExistsAsync(new Database { Id = "graphdb" });

        DocumentCollection graph = await client.CreateDocumentCollectionIfNotExistsAsync(
            UriFactory.CreateDatabaseUri("graphdb"),
            new DocumentCollection { Id = "Custom" },
            new RequestOptions { OfferThroughput = 1000 });

        // Azure Cosmos DB supports the Gremlin API for working with Graphs. Gremlin is a functional programming language composed of steps.
        // Here, we run a series of Gremlin queries to show how you can add vertices, edges, modify properties, perform queries and traversals
        // For additional details, see https://aka.ms/gremlin for the complete list of supported Gremlin operators
        var custom = new Custom
        {
            Name = "Tom",
            Type = "1"
        };
        var s = CovertToGremlinString(custom, "custom");
        Dictionary<string, string> gremlinQueries = new Dictionary<string, string>
        {
            {"Cleanup", "g.V().drop()"},
            {"AddVertex 1", s}
        };

        foreach (KeyValuePair<string, string> gremlinQuery in gremlinQueries)
        {
            Console.WriteLine($"Running {gremlinQuery.Key}: {gremlinQuery.Value}");


            // The CreateGremlinQuery method extensions allow you to execute Gremlin queries and iterate
            // results asychronously
            IDocumentQuery<dynamic> query = client.CreateGremlinQuery<dynamic>(graph, (string) gremlinQuery.Value);
            while (query.HasMoreResults)
            {
                foreach (dynamic result in await query.ExecuteNextAsync())
                {
                    Console.WriteLine($"\t {JsonConvert.SerializeObject(result)}");
                }
            }

            Console.WriteLine();
        }

5.Test it on the local.

    string endpoint = ConfigurationManager.AppSettings["Endpoint"];
    string authKey = ConfigurationManager.AppSettings["AuthKey"];

    using (DocumentClient client = new DocumentClient(
                new Uri(endpoint),
                authKey,
                new ConnectionPolicy { ConnectionMode = ConnectionMode.Direct, ConnectionProtocol = Protocol.Tcp }))
            {
                Program p = new Program();
                p.RunAsync(client).Wait();
            }

packages.config

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="Microsoft.Azure.DocumentDB" version="1.14.0" targetFramework="net452" />
  <package id="Microsoft.Azure.Graphs" version="0.2.0-preview" targetFramework="net452" />
  <package id="Microsoft.CodeAnalysis.Analyzers" version="1.1.0" targetFramework="net452" />
  <package id="Microsoft.CodeAnalysis.Common" version="1.3.0" targetFramework="net452" />
  <package id="Microsoft.CodeAnalysis.CSharp" version="1.3.0" targetFramework="net452" />
  <package id="Newtonsoft.Json" version="6.0.8" targetFramework="net452" />
  <package id="System.Collections" version="4.0.0" targetFramework="net452" />
  <package id="System.Collections.Immutable" version="1.1.37" targetFramework="net452" />
  <package id="System.Diagnostics.Debug" version="4.0.0" targetFramework="net452" />
  <package id="System.Globalization" version="4.0.0" targetFramework="net452" />
  <package id="System.Linq" version="4.0.0" targetFramework="net452" />
  <package id="System.Reflection.Metadata" version="1.2.0" targetFramework="net452" />
  <package id="System.Resources.ResourceManager" version="4.0.0" targetFramework="net452" />
  <package id="System.Runtime" version="4.0.0" targetFramework="net452" />
  <package id="System.Runtime.Extensions" version="4.0.0" targetFramework="net452" />
  <package id="System.Threading" version="4.0.0" targetFramework="net452" />
</packages>