NullReferenceException

[truegoodwill]

This was found in my Orleans log. I'm guessing this happened because the collection was not already present in the db?

fail: Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage[102202]
      Error from storage provider MongoGrainStorage.Orleans.Streams.PubSubRendezvousGrain during ReadState for grain Type=Orleans.Streams.PubSubRendezvousGrain Pk=*grn/716E8E94/0057c0be-1193-4837-a51a-83d1a74cac95+ORLEANS_SIGNALR_STREAM_PROVIDER_SERVERS_STREAM-0x5B52D524 Id=GrainReference:*grn/716E8E94/0057c0be-1193-4837-a51a-83d1a74cac95+ORLEANS_SIGNALR_STREAM_PROVIDER_SERVERS_STREAM Error=

      Exc level 0: System.NullReferenceException: Object reference not set to an instance of an object.
         at Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage.GetCollection(String grainType)
         at Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage.<>c__DisplayClass19_0.<<ReadStateAsync>b__0>d.MoveNext()
      --- End of stack trace from previous location ---
         at Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage.<>c__DisplayClass23_0.<<DoAndLog>b__0>d.MoveNext()
      --- End of stack trace from previous location ---
         at Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage.DoAndLog[T](String actionName, Func`1 action)
         at Orleans.Core.StateStorageBridge`1.ReadStateAsync()
      System.NullReferenceException: Object reference not set to an instance of an object.
         at Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage.GetCollection(String grainType)
         at Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage.<>c__DisplayClass19_0.<<ReadStateAsync>b__0>d.MoveNext()
      --- End of stack trace from previous location ---
         at Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage.<>c__DisplayClass23_0.<<DoAndLog>b__0>d.MoveNext()
      --- End of stack trace from previous location ---
         at Orleans.Providers.MongoDB.StorageProviders.MongoGrainStorage.DoAndLog[T](String actionName, Func`1 action)
         at Orleans.Core.StateStorageBridge`1.ReadStateAsync()

Configuration:

.UseMongoDBClient(mongoOptions.ConnectionString)
      .UseMongoDBClustering(options =>
      {
        options.DatabaseName = $"{mongoOptions.DBNamePrefix}-Clustering";
        options.Strategy = MongoDBMembershipStrategy.SingleDocument;
      })
      .UseMongoDBReminders(options =>
      {
        options.DatabaseName = $"{mongoOptions.DBNamePrefix}-Reminders";
      })
      .AddMongoDBGrainStorage("default", optionsBuilder => optionsBuilder.Configure(options =>
      {
        options.DatabaseName = $"{mongoOptions.DBNamePrefix}-DefaultStorage";
        options.ConfigureJsonSerializerSettings = serializerSettings =>
        {
          serializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Include;
          serializerSettings.ObjectCreationHandling = Newtonsoft.Json.ObjectCreationHandling.Replace;
          serializerSettings.DefaultValueHandling = Newtonsoft.Json.DefaultValueHandling.Populate;
          serializerSettings.Converters.Add(new Newtonsoft.Json.Converters.StringEnumConverter());
          serializerSettings.Converters.Add(DirectionConverterForNewtonsoft.Instance);
        };
      }))
      .AddMongoDBGrainStorage("PubSubStore", options =>
      {
        options.DatabaseName = $"{mongoOptions.DBNamePrefix}-PubSubStore";
        options.ConfigureJsonSerializerSettings = serializerSettings =>
        {
          serializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Include;
          serializerSettings.ObjectCreationHandling = Newtonsoft.Json.ObjectCreationHandling.Replace;
          serializerSettings.DefaultValueHandling = Newtonsoft.Json.DefaultValueHandling.Populate;
          serializerSettings.Converters.Add(new Newtonsoft.Json.Converters.StringEnumConverter());
          serializerSettings.Converters.Add(DirectionConverterForNewtonsoft.Instance);
        };
      })
      .AddSimpleMessageStreamProvider(Streams.StreamProvider, options =>
      {
        options.FireAndForgetDelivery = true;
        options.OptimizeForImmutableData = true;
        options.PubSubType = Orleans.Streams.StreamPubSubType.ExplicitGrainBasedOnly;
      })

[SebastianStehle]

I added a very simple streaming scenario, but I cannot reproduce it.