Adding index_template_substitutions to the simulate ingest API

docs/changelog/114128.yaml

@@ -0,0 +1,5 @@
+pr: 114128
+summary: Adding `index_template_substitutions` to the simulate ingest API
+area: Ingest Node
+type: enhancement
+issues: []

docs/reference/indices/put-index-template.asciidoc

@@ -85,6 +85,8 @@ include::{docdir}/rest-api/common-parms.asciidoc[tag=master-timeout]
 [[put-index-template-api-request-body]]
 ==== {api-request-body-title}
 
+// tag::request-body[]
+
 `composed_of`::
 (Optional, array of strings)
 An ordered list of component template names. Component templates are merged in the order
@@ -102,7 +104,7 @@ See <<create-index-template,create an index template>>.
 +
 .Properties of `data_stream`
 [%collapsible%open]
-====
+=====
 `allow_custom_routing`::
 (Optional, Boolean) If `true`, the data stream supports
 <<mapping-routing-field,custom routing>>. Defaults to `false`.
@@ -117,7 +119,7 @@ See <<create-index-template,create an index template>>.
 +
 If `time_series`, each backing index has an `index.mode` index setting of
 `time_series`.
-====
+=====
 
 `index_patterns`::
 (Required, array of strings)
@@ -146,7 +148,7 @@ Template to be applied. It may optionally include an `aliases`, `mappings`, or
 +
 .Properties of `template`
 [%collapsible%open]
-====
+=====
 `aliases`::
 (Optional, object of objects) Aliases to add.
 +
@@ -161,7 +163,7 @@ include::{es-ref-dir}/indices/create-index.asciidoc[tag=aliases-props]
 include::{docdir}/rest-api/common-parms.asciidoc[tag=mappings]
 
 include::{docdir}/rest-api/common-parms.asciidoc[tag=settings]
-====
+=====
 
 `version`::
 (Optional, integer)
@@ -174,6 +176,7 @@ Marks this index template as deprecated.
 When creating or updating a non-deprecated index template that uses deprecated components,
 {es} will emit a deprecation warning.
 // end::index-template-api-body[]
+// end::request-body[]
 
 [[put-index-template-api-example]]
 ==== {api-examples-title}

docs/reference/ingest/apis/simulate-ingest.asciidoc

@@ -102,13 +102,21 @@ POST /_ingest/_simulate
         }
       }
     }
+  },
+  "index_template_substitutions": { <3>
+    "my-index-template": {
+      "index_patterns": ["my-index-*"],
+      "composed_of": ["component_template_1", "component_template_2"]
+    }
   }
 }
 ----
 
 <1> This replaces the existing `my-pipeline` pipeline with the contents given here for the duration of this request.
 <2> This replaces the existing `my-component-template` component template with the contents given here for the duration of this request.
 These templates can be used to change the pipeline(s) used, or to modify the mapping that will be used to validate the result.
+<3> This replaces the existing `my-index-template` index template with the contents given here for the duration of this request.
+These templates can be used to change the pipeline(s) used, or to modify the mapping that will be used to validate the result.
 
 [[simulate-ingest-api-request]]
 ==== {api-request-title}
@@ -225,6 +233,19 @@ include::{es-ref-dir}/indices/put-component-template.asciidoc[tag=template]
 
 ====
 
+`index_template_substitutions`::
+(Optional, map of strings to objects)
+Map of index template names to substitute index template definition objects.
++
+.Properties of index template definition objects
+[%collapsible%open]
+
+====
+
+include::{es-ref-dir}/indices/put-index-template.asciidoc[tag=request-body]
+
+====
+
 [[simulate-ingest-api-example]]
 ==== {api-examples-title}