How to create an index template with NGramTokenizer using .NET client 8.0

Elastic Stack Elasticsearch
4

Thanks Steve, now I can create this template as expected.

Follow-up: I also want to read this template in order to verify if its contents are correct. But the following request for getting this template throws an Exception:

var getIndexTemplateResponse = await _elasticClient.Indices.GetIndexTemplateAsync(d => d
	.Name(templateName));

The templateName is myindex_template.

The exception is

Elastic.Transport.UnexpectedTransportException: The JSON value could not be converted to Elastic.Clients.Elasticsearch.Names. Path: $.index_templates[0].index_template.index_patterns | LineNumber: 5 | BytePositionInLine: 28. ---> System.Text.Json.JsonException: The JSON value could not be converted to Elastic.Clients.Elasticsearch.Names. Path: $.index_templates[0].index_template.index_patterns | LineNumber: 5 | BytePositionInLine: 28.
   bei System.Text.Json.ThrowHelper.ThrowJsonException_DeserializeUnableToConvertValue(Type propertyType)
   bei System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.Metadata.JsonPropertyInfo`1.ReadJsonAndSetMember(Object obj, ReadStack& state, Utf8JsonReader& reader)
   bei System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.Metadata.JsonPropertyInfo`1.ReadJsonAndSetMember(Object obj, ReadStack& state, Utf8JsonReader& reader)
   bei System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.JsonCollectionConverter`2.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, TCollection& value)
   bei System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.Metadata.JsonPropertyInfo`1.ReadJsonAndSetMember(Object obj, ReadStack& state, Utf8JsonReader& reader)
   bei System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   bei System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   bei System.Text.Json.JsonSerializer.ReadCore[TValue](JsonReaderState& readerState, Boolean isFinalBlock, ReadOnlySpan`1 buffer, JsonSerializerOptions options, ReadStack& state, JsonConverter converterBase)
   bei System.Text.Json.JsonSerializer.ContinueDeserialize[TValue](ReadBufferState& bufferState, JsonReaderState& jsonReaderState, ReadStack& readStack, JsonConverter converter, JsonSerializerOptions options)
   bei System.Text.Json.JsonSerializer.<ReadAllAsync>d__65`1.MoveNext()

This is the template as seen in Kibana (Kibana and ES 8.2.3)

{
  "template": {
    "settings": {
      "index": {
        "analysis": {
          "analyzer": {
            "fta": {
              "filter": [
                "lowercase"
              ],
              "type": "custom",
              "tokenizer": "ftt"
            }
          },
          "tokenizer": {
            "ftt": {
              "token_chars": [
                "letter",
                "digit",
                "punctuation",
                "symbol"
              ],
              "min_gram": "3",
              "type": "ngram",
              "max_gram": "3"
            }
          }
        },
        "routing": {
          "allocation": {
            "include": {
              "_tier_preference": "data_content"
            }
          }
        },
        "default_pipeline": "myindex_pipeline"
      }
    },
    "aliases": {},
    "mappings": {}
  }
}