# Write structured log but field is never recognized as 'date'
**URL:** https://discuss.elastic.co/t/write-structured-log-but-field-is-never-recognized-as-date/348920
**Category:** Elasticsearch
**Created:** [December 8, 2023, 3:46pm UTC](https://discuss.elastic.co/t/write-structured-log-but-field-is-never-recognized-as-date/348920 "2023-12-08T15:46:21Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Heija](https://discuss.elastic.co/u/Heija)
#### Post date: [December 8, 2023, 3:46pm UTC](https://discuss.elastic.co/t/write-structured-log-but-field-is-never-recognized-as-date/348920/1 "2023-12-08T15:46:21Z")
Hi!
I have a .net application which write log entries per nlog direct to Elasticsearch.
It works with strings, numbers and booleans.
Now I need to transfer a 'date' as structured log entry to Elasticsearch, but it will always just recognized as type 'keyword' doesn´t matter what format I choose.
For example:
```auto
logger.LogInformation("{mydate}",DateTime.Now.ToString("yyyy-MM-dd");
```
The only way it worked is when I write into elasticsearch console
```auto
PUT *myIndex*/_mapping
{
"properties": {
"mydate": {
"type": "date",
"format": "yyyy-MM-dd"
}
}
}
```
before I log the first entry from my application.
But this is not a good solution and I don´t see how I can automatically configurate this.
Any help whould be great!
---
### Author:  [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)
#### Post date: [December 8, 2023, 3:48pm UTC](https://discuss.elastic.co/t/write-structured-log-but-field-is-never-recognized-as-date/348920/2 "2023-12-08T15:48:55Z")
I would recommend you specify the mapping through an [index template](https://www.elastic.co/guide/en/elasticsearch/reference/8.11/index-templates.html). That way the mapping will be applied when the index is created.
---
### Author:  [@Heija](https://discuss.elastic.co/u/Heija)
#### Post date: [December 11, 2023, 12:01pm UTC](https://discuss.elastic.co/t/write-structured-log-but-field-is-never-recognized-as-date/348920/3 "2023-12-11T12:01:29Z")
Thanks for your reply.
I forgot to mention that we use ES 7.17.
It seems that [updating runtime fields](https://www.elastic.co/guide/en/elasticsearch/reference/7.17/runtime-mapping-fields.html#runtime-updating-scripts) work.
```auto
PUT *myIndex*/_mapping
{
"runtime" : {
"mydate": {
"type": "date"
}
}
}
```
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [January 8, 2024, 12:01pm UTC](https://discuss.elastic.co/t/write-structured-log-but-field-is-never-recognized-as-date/348920/4 "2024-01-08T12:01:53Z")
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