How does attribute mapping for the NEST Elasticsearch client work for date times

Question

I have a C# object that I am using to index documents to an existing type in Elasticsearch.

The object has a DateTime field that I want to configure the mapping using the the NEST clients attribute based mapping. I am looking to configure the format as DateFormat.basic_date_time_no_millis. I am hopping that this will strip out the milliseconds from the date time object. The class being used as the document to index is below.

public class DBQueueDepth
{
    public string QueueName { get; set; }
    public int ProcessedCount { get; set; }
    public int NotProcessedCount { get; set; }
    public string Environment { get; set; }

    [Date(Format = DateFormat.basic_date_time_no_millis)]
    public DateTime SampleTimeStamp { get; set; }
}

The type being mapped to in Elasticsearch is;

    "dbQueueDepth": {
    "properties": {
      "environment": {
        "type": "text"
      },
      "notProcessedCount": {
        "type": "integer"
      },
      "processedCount": {
        "type": "integer"
      },
      "queueName": {
        "type": "text"
      },
      "sampleTimeStamp": {
        "type": "date",
        "format": "date_time_no_millis"
      }
    }

My client code is

        var node = new Uri("http://localhost:9200");

        var settings =
            new ConnectionSettings(node).MaximumRetries(10)
                .MaxRetryTimeout(new TimeSpan(0, 0, 0, 10))
                .DefaultIndex("austin_operational_data")
                .InferMappingFor<DBQueueDepth>(i => i.TypeName("dbQueueDepth"));


        ElasticClient client = new ElasticClient(settings);
        var response = client.IndexMany(rows);

When I try and index the document I receive the following error.

{index returned 400 _index: operational_data _type: dbQueueDepth _id: AV5rqc3g6arLsAmJzpLK _version: 0 error: Type: mapper_parsing_exception Reason: "failed to parse [sampleTimeStamp]" CausedBy: Type: illegal_argument_exception Reason: "Invalid format: "2017-09-10T12:00:41.9926558Z" is malformed at ".9926558Z""}

Am I correct in expecting the NEST client to strip out the milliseconds based on the formatting in the Date Attribute ?

Is the InferMappingFor method instructing the client to use the formatting designated by attributes on the C# object?

Russ Cam · Accepted Answer · 2017-09-11T02:18:35.873

Your assumption is not quite right. The format on a date field controls how the date string in the request will be parsed on the server side in Elasticsearch i.e. it tells Elasticsearch in what format to expect the string.

Now, you could use format in conjunction with a JsonConverter to serialize DateTime into a format that does not emit the milliseconds. However, I would probably approach this instead by removing the milliseconds from the DateTime instance within application code (perhaps in the property setter) and leaving the format and serialization as is.

How does attribute mapping for the NEST Elasticsearch client work for date times

1 Answers1