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Simulate index API

Returns the index configuration that would be applied to the specified index from an existing index template.

resp = client.indices.simulate_index_template(
    name="my-index-000001",
)
print(resp)

const response = await client.indices.simulateIndexTemplate({
  name: "my-index-000001",
});
console.log(response);

POST /_index_template/_simulate_index/my-index-000001

Request

POST /_index_template/_simulate_index/<index>

Prerequisites

If the Elasticsearch security features are enabled, you must have the manage_index_templates or manage cluster privilege to use this API.

Path parameters

<index>: (Required, string) Name of the index to simulate.

Query parameters

master_timeout: (Optional, time units) Period to wait for the master node. If the master node is not available before the timeout expires, the request fails and returns an error. Defaults to 30s. Can also be set to -1 to indicate that the request should never timeout.
include_defaults: (Optional, Boolean) Functionality in [preview] This functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features. . If true, return all default settings in the response. Defaults to false.

Response body

overlapping

(array) Any templates that also matched the index but were superseded by a higher-priority template. Response includes an empty array if there are no overlapping templates.

Properties of overlapping

name: (string) Name of the superseded template.
index_patterns: (array) Index patterns that the superseded template applies to.

template

(object) The settings, mappings, and aliases that would be applied to the index.

Properties of template

aliases

(object) Aliases for the index. If no aliases apply, the response returns an empty aliases object.

<alias>

(object) The key is the alias name. The object body contains options for the alias.

Properties of <alias>

filter: (Query DSL object) Query used to limit documents the alias can access.
index_routing: (string) Value used to route indexing operations to a specific shard. This overwrites the routing value for indexing operations.
is_hidden: (Boolean) If true, the alias is hidden.
is_write_index: (Boolean) If true, the index is the write index for the alias.
routing: (string) Value used to route indexing and search operations to a specific shard.
search_routing: (string) Value used to route search operations to a specific shard. This overwrites the routing value for search operations.

mappings

(Optional, mapping object) Mapping for fields in the index. If specified, this mapping can include:

See Mapping.

Omitted from the response if no mappings would be applied.

settings

(Optional, index setting object) Configuration options for the index. See Index settings.

Response includes an empty object if no settings would be applied.

Examples

The following example shows the configuration that would be applied to my-index-000001 by an existing template.

resp = client.cluster.put_component_template(
    name="ct1",
    template={
        "settings": {
            "index.number_of_shards": 2
        }
    },
)
print(resp)

resp1 = client.cluster.put_component_template(
    name="ct2",
    template={
        "settings": {
            "index.number_of_replicas": 0
        },
        "mappings": {
            "properties": {
                "@timestamp": {
                    "type": "date"
                }
            }
        }
    },
)
print(resp1)

resp2 = client.indices.put_index_template(
    name="final-template",
    index_patterns=[
        "my-index-*"
    ],
    composed_of=[
        "ct1",
        "ct2"
    ],
    priority=5,
)
print(resp2)

resp3 = client.indices.simulate_index_template(
    name="my-index-000001",
)
print(resp3)

response = client.cluster.put_component_template(
  name: 'ct1',
  body: {
    template: {
      settings: {
        'index.number_of_shards' => 2
      }
    }
  }
)
puts response

response = client.cluster.put_component_template(
  name: 'ct2',
  body: {
    template: {
      settings: {
        'index.number_of_replicas' => 0
      },
      mappings: {
        properties: {
          "@timestamp": {
            type: 'date'
          }
        }
      }
    }
  }
)
puts response

response = client.indices.put_index_template(
  name: 'final-template',
  body: {
    index_patterns: [
      'my-index-*'
    ],
    composed_of: [
      'ct1',
      'ct2'
    ],
    priority: 5
  }
)
puts response

const response = await client.cluster.putComponentTemplate({
  name: "ct1",
  template: {
    settings: {
      "index.number_of_shards": 2,
    },
  },
});
console.log(response);

const response1 = await client.cluster.putComponentTemplate({
  name: "ct2",
  template: {
    settings: {
      "index.number_of_replicas": 0,
    },
    mappings: {
      properties: {
        "@timestamp": {
          type: "date",
        },
      },
    },
  },
});
console.log(response1);

const response2 = await client.indices.putIndexTemplate({
  name: "final-template",
  index_patterns: ["my-index-*"],
  composed_of: ["ct1", "ct2"],
  priority: 5,
});
console.log(response2);

const response3 = await client.indices.simulateIndexTemplate({
  name: "my-index-000001",
});
console.log(response3);

PUT /_component_template/ct1                    
{
  "template": {
    "settings": {
      "index.number_of_shards": 2
    }
  }
}

PUT /_component_template/ct2                    
{
  "template": {
    "settings": {
      "index.number_of_replicas": 0
    },
    "mappings": {
      "properties": {
        "@timestamp": {
          "type": "date"
        }
      }
    }
  }
}

PUT /_index_template/final-template             
{
  "index_patterns": ["my-index-*"],
  "composed_of": ["ct1", "ct2"],
  "priority": 5
}

POST /_index_template/_simulate_index/my-index-000001

	Create a component template (`ct1`) that sets the number of shards to 2
	Create a second component template (`ct2`) that sets the number of replicas to 0 and defines a mapping
	Create an index template (`final-template`) that uses the component templates
	Show the configuration that would be applied to `my-index-000001`

The response shows the index settings, mappings, and aliases applied by the final-template:

{
  "template" : {
    "settings" : {
      "index" : {
        "number_of_shards" : "2",
        "number_of_replicas" : "0",
        "routing" : {
          "allocation" : {
            "include" : {
              "_tier_preference" : "data_content"
            }
          }
        }
      }
    },
    "mappings" : {
      "properties" : {
        "@timestamp" : {
          "type" : "date"
        }
      }
    },
    "aliases" : { }
  },
  "overlapping" : [
    {
      "name" : "template_1",
      "index_patterns" : [
        "my-index-*"
      ]
    }
  ]
}

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https://www.elastic.co/guide/en/elasticsearch/reference/8.17/indices-simulate-index.html