# Dynamic Templates: path\_match with regex matching producing unintentional results

**URL:** https://discuss.elastic.co/t/dynamic-templates-path-match-with-regex-matching-producing-unintentional-results/356016
**Category:** Elasticsearch
**Created:** [March 22, 2024, 8:13pm UTC](https://discuss.elastic.co/t/dynamic-templates-path-match-with-regex-matching-producing-unintentional-results/356016 "2024-03-22T20:13:30Z")
**Posts on this page:** 4
**Page:** 1

<div class="post-metadata">

### Author: ![nkachami](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@nkachami](https://discuss.elastic.co/u/nkachami)
#### Post date: [March 22, 2024, 8:13pm UTC](https://discuss.elastic.co/t/dynamic-templates-path-match-with-regex-matching-producing-unintentional-results/356016/1 "2024-03-22T20:13:31Z")

</div>

Below is a mock index that contains a dynamic template utilizing path\_match with regex to index specifically named objects into an Elasticsearch schema.

```auto
{
    "settings": {# settings
    },
    "mappings": {
        "dynamic": "strict",
        "dynamic_templates": [
            {
                "some_template": {
                    "match_pattern": "regex",
                    "path_match": "top_level_field.(sub_level_field1|sub_level_field2|sub_level_fieldx)..*",
                    "mapping": {
                        "type": "object",
                        "properties": {# identical properties of specifically named sub_level_fields
                        }
                    }
                }
            }
        ],
        "properties": {
            "top_level_field": {
                "type": "object",
                "dynamic": true
            },
            # more properties
        }
    }
}

```

With the template above, I should expect to be able to index:

```auto
{
  "top_level_field": {
    "sub_level_field1": {
      # properties
    }
  }
}

```

I should also expect **not** to be able to index

```auto
{
  "top_level_field": {
    "non_listed_sub_level_field": {
      # properties
    }
  }
}

```

But, both can be indexed. Does path\_match not function the same way match does with regex or am I missing something?

Thanks

---

<div class="post-metadata">

### Author: ![demjened](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/demjened/32/109159_2.png) [@demjened](https://discuss.elastic.co/u/demjened)
#### Post date: [March 22, 2024, 9:13pm UTC](https://discuss.elastic.co/t/dynamic-templates-path-match-with-regex-matching-producing-unintentional-results/356016/2 "2024-03-22T21:13:49Z")

</div>

Hello Nicholas, welcome to the forum!

`path_match` is not regex but takes a path syntax. Looking at your dynamic mapping definition I see an extra dot at the end of the expression that might be there by accident.

I tried setting up the index like this:

```auto
PUT dyntest
{
    "mappings": {
        "dynamic": "strict",
        "dynamic_templates": [
            {
                "some_template": {
                    "match_pattern": "regex",
                    "path_match": "top_level_field.(sub_level_field1|sub_level_field2|sub_level_fieldx).*", // just one dot in .*
                    "mapping": {
                        "type": "object",
                        "properties": {
                          "subfield": {
                            "type": "keyword"
                          }
                        }
                    }
                }
            }
        ],
        "properties": {
            "top_level_field": {
                "type": "object",
                "dynamic": true
            }
        }
    }
}

```

This way the `some_template` mapping applies to `top_level_field.sub_level_field1.subfield`, `top_level_field.sub_level_field2.subfield` and so on, and it will map it as keyword.

Since `top_level_field` is dynamic, it can take other sub-fields that do not match for the template, for those the default mapping will apply.

```auto
PUT dyntest/_doc/1
{
  "top_level_field": {
    "sub_level_field1": {
      "subfield": "foo"
    },
    "non_listed_sub_level_field": {
      "accepts_anything": true
    }
  }
}

GET dyntest/_mapping

...
"properties": {
  "top_level_field": {
    "dynamic": "true",
    "properties": {
      "non_listed_sub_level_field": {
        "properties": {
          "accepts_anything": {
            "type": "boolean" // Did not apply dynamic template
          }
        }
      },
      "sub_level_field1": {
        "properties": {
          "subfield": {
            "type": "keyword" // Applied dynamic template
          }
        }
      }
    }
  }
}

```

Hope I understood the problem correctly and this answers your question!

---

<div class="post-metadata">

### Author: ![nkachami](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@nkachami](https://discuss.elastic.co/u/nkachami)
#### Post date: [March 22, 2024, 9:43pm UTC](https://discuss.elastic.co/t/dynamic-templates-path-match-with-regex-matching-producing-unintentional-results/356016/3 "2024-03-22T21:43:48Z")

</div>

Thanks for the quick response Adam. This makes sense, I thought that template may limit the top level field to only accept a singular sub field or in this case the list of fields within the regex, but because its marked as dynamic, I see that is not the case. Thanks for the response!

---

<div class="post-metadata">

### Author: ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)
#### Post date: [April 19, 2024, 9:43pm UTC](https://discuss.elastic.co/t/dynamic-templates-path-match-with-regex-matching-producing-unintentional-results/356016/4 "2024-04-19T21:43:49Z")

</div>

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