ElasticSearch services throw an exception while trying to search for related documents

[MikeAlhayek]

Describe the bug

When using Elasticsearch service, I am seeing the following in my logs

ElasticSearch services throw an exception while trying to search for related documents. Elasticsearch.Net.UnexpectedElasticsearchClientException: Index name is null for the given type and no default index is set. Map an index name using ConnectionSettings.DefaultMappingFor<TDocument>() or set a default index using ConnectionSettings.DefaultIndex().
 ---> System.ArgumentException: Index name is null for the given type and no default index is set. Map an index name using ConnectionSettings.DefaultMappingFor<TDocument>() or set a default index using ConnectionSettings.DefaultIndex().
   at Nest.IndexNameResolver.ValidateIndexName(String indexName)
   at Nest.IndexNameResolver.Resolve(Type type)
   at Nest.IndexNameResolver.Resolve(IndexName i)
   at Nest.IndexNameFormatter.Serialize(JsonWriter& writer, IndexName value, IJsonFormatterResolver formatterResolver)
   at Elasticsearch.Net.Nest_ILikeDocumentFormatter4.Serialize(JsonWriter&, ILikeDocument, IJsonFormatterResolver)
   at Nest.UnionFormatter`2.Serialize(JsonWriter& writer, Union`2 value, IJsonFormatterResolver formatterResolver)
   at Nest.LikeFormatter.Serialize(JsonWriter& writer, Like value, IJsonFormatterResolver formatterResolver)
   at Elasticsearch.Net.Utf8Json.Formatters.CollectionFormatterBase`4.Serialize(JsonWriter& writer, TCollection value, IJsonFormatterResolver formatterResolver)
   at Elasticsearch.Net.Nest_IMoreLikeThisQueryFormatter3.Serialize(JsonWriter&, IMoreLikeThisQuery, IJsonFormatterResolver)
   at Elasticsearch.Net.Nest_IQueryContainerFormatter2.Serialize(JsonWriter&, IQueryContainer, IJsonFormatterResolver)
   at Nest.QueryContainerInterfaceFormatter.Serialize(JsonWriter& writer, IQueryContainer value, IJsonFormatterResolver formatterResolver)
   at Nest.QueryContainerFormatter.Serialize(JsonWriter& writer, QueryContainer value, IJsonFormatterResolver formatterResolver)
   at Elasticsearch.Net.Nest_ISearchRequestFormatter1.Serialize(JsonWriter&, ISearchRequest, IJsonFormatterResolver)
   at Elasticsearch.Net.Utf8Json.JsonSerializer.SerializeAsync[T](Stream stream, T value, IJsonFormatterResolver resolver)
   at Elasticsearch.Net.SerializableData`1.WriteAsync(Stream writableStream, IConnectionConfigurationValues settings, CancellationToken cancellationToken)
   at Elasticsearch.Net.HttpConnection.SetContentAsync(HttpRequestMessage message, RequestData requestData, CancellationToken cancellationToken)
   at Elasticsearch.Net.HttpConnection.RequestAsync[TResponse](RequestData requestData, CancellationToken cancellationToken)
   at Elasticsearch.Net.RequestPipeline.CallElasticsearchAsync[TResponse](RequestData requestData, CancellationToken cancellationToken)
   at Elasticsearch.Net.Transport`1.RequestAsync[TResponse](HttpMethod method, String path, CancellationToken cancellationToken, PostData data, IRequestParameters requestParameters)
   --- End of inner exception stack trace ---
   at Elasticsearch.Net.Transport`1.RequestAsync[TResponse](HttpMethod method, String path, CancellationToken cancellationToken, PostData data, IRequestParameters requestParameters)
   at Nest.ElasticClient.SearchAsync[TDocument](ISearchRequest request, CancellationToken ct)
   at OrchardCore.Search.Elasticsearch.Core.Services.ElasticIndexManager.SearchAsync(String indexName, QueryContainer query, List`1 sort, Int32 from, Int32 size)
   at OrchardCore.Search.Elasticsearch.Core.Services.ElasticSearchQueryService.ExecuteQueryAsync(String indexName, QueryContainer query, List`1 sort, Int32 from, Int32 size)
   at CloudSolutions.Knowledges.Drivers.RelatedContentPartDisplayDriver.<>c__DisplayClass7_0.<<DisplayAsync>b__0>d.MoveNext() in /app/Modules/CloudSolutions.Knowledges/Drivers/RelatedContentPartDisplayDriver.cs:line 108    at Elasticsearch.Net.Transport`1.RequestAsync[TResponse](HttpMethod method, String path, CancellationToken cancellationToken, PostData data, IRequestParameters requestParameters)
   at Nest.ElasticClient.SearchAsync[TDocument](ISearchRequest request, CancellationToken ct)
   at OrchardCore.Search.Elasticsearch.Core.Services.ElasticIndexManager.SearchAsync(String indexName, QueryContainer query, List`1 sort, Int32 from, Int32 size)
   at OrchardCore.Search.Elasticsearch.Core.Services.ElasticSearchQueryService.ExecuteQueryAsync(String indexName, QueryContainer query, List`1 sort, Int32 from, Int32 size)

My RelatedContentDisplayDriver queries related documents like this

            try
            {
                var query = new MoreLikeThisQuery()
                {
                    Fields = searchSettings.DefaultSearchFields,
                    Analyzer = await _serviceProvider.GetRequiredService<ElasticIndexSettingsService>().GetQueryAnalyzerAsync(indexName),
                    Like =
                    [
                        new(new LikeDocument<ContentItem>(new Id(part.ContentItem.ContentItemId)))
                    ],
                    MinDocumentFrequency = settings.MinDocumentFrequency,
                    MaxDocumentFrequency = settings.MaxDocumentFrequency,
                    MinTermFrequency = settings.MinTermFrequency,
                    MaxQueryTerms = settings.MaxQueryTerms,
                    MinWordLength = settings.MinWordLength,
                    MaxWordLength = settings.MaxWordLength,
                };

                var contentItemIds = await searchQueryService.ExecuteQueryAsync(indexName, query, null, 0, 20);

                if (contentItemIds.Count > 0)
                {
                    var contentItems = await _session.Query<ContentItem, ContentItemIndex>()
                    .ListAsync();

                    model.ContentItems = contentItems.OrderBy(x => contentItemIds.IndexOf(x.ContentItemId))
                    .Take(settings.TotalVisible)
                    .ToArray();
                }
                else
                {
                    model.ContentItems = [];
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "ElasticSearch services throw an exception while trying to search for related documents.");
            }

I think there is an issue in the ElasticIndexManager.SearchAsync(indexName, query, sort, from, size)

Orchard Core version

1.x and 2.x