Add docs for QueryApiKey API (elastic#76521)

This PR adds documentation for the new QueryApiKey API added in elastic#75335 and elastic#76144

Relates: elastic#71023

x-pack/docs/en/rest-api/security/get-api-keys.asciidoc

@@ -179,7 +179,7 @@ A successful call returns a JSON structure that contains the information of one
 {
   "api_keys": [ <1>
     {
-      "id": "dGhpcyBpcyBub3QgYSByZWFsIHRva2VuIGJ1dCBpdCBpcyBvbmx5IHRlc3QgZGF0YS4gZG8gbm90IHRyeSB0byByZWFkIHRva2VuIQ==", <2>
+      "id": "0GF5GXsBCXxz2eDxWwFN", <2>
       "name": "hadoop_myuser_key", <3>
       "creation": 1548550550158, <4>
       "expiration": 1548551550158, <5>
@@ -191,7 +191,7 @@ A successful call returns a JSON structure that contains the information of one
       }
     },
     {
-      "id": "api-key-id-2",
+      "id": "6wHJmcQpReKBa42EHV5SBw",
       "name": "api-key-name-2",
       "creation": 1548550550158,
       "invalidated": false,

x-pack/docs/en/rest-api/security/query-api-key.asciidoc

@@ -0,0 +1,334 @@
+[role="xpack"]
+[[security-api-query-api-key]]
+=== Query API key information API
+
+++++
+<titleabbrev>Query API key information</titleabbrev>
+++++
+
+Retrieves information for API keys with <<query-dsl,Query DSL>>
+in a <<paginate-search-results,paginated>> fashion.
+
+[[security-api-query-api-key-request]]
+==== {api-request-title}
+
+`GET /_security/_query/api_key`
+
+`POST /_security/_query/api_key`
+
+[[security-api-query-api-key-prereqs]]
+==== {api-prereq-title}
+
+* To use this API, you must have at least the `manage_own_api_key` cluster
+privilege.
+* If you have only the `manage_own_api_key` privilege, this API returns only
+the API keys that you own. If you have the `manage_api_key` or greater
+privileges (including `manage_security`), this API returns all API keys
+regardless of ownership.
+
+[[security-api-query-api-key-desc]]
+==== {api-description-title}
+
+Use this API to retrieve the API keys created with the
+<<security-api-create-api-key,create API key API>> in a paginated manner.
+You can optionally filter the results with a query.
+
+[[security-api-query-api-key-request-body]]
+==== {api-request-body-title}
+
+You can specify the following parameters in the request body:
+
+`query`::
+(Optional, string) A <<query-dsl,query>> to filter which API keys to return.
+The query supports a subset of query types, including
+<<query-dsl-match-all-query,`match_all`>>, <<query-dsl-bool-query,`bool`>>,
+<<query-dsl-term-query,`term`>>, <<query-dsl-terms-query,`terms`>>, <<query-dsl-ids-query,`ids`>>,
+<<query-dsl-prefix-query,`prefix`>>, <<query-dsl-wildcard-query,`wildcard`>>, and <<query-dsl-range-query,`range`>>.
++
+You can query all public information associated with an API key, including the
+following values.
++
+.Valid values for `query`
+[%collapsible%open]
+====
+`id`::
+ID of the API key. Note `id` must be queried with the <<query-dsl-ids-query,`ids`>> query.
+
+`name`::
+Name of the API key.
+
+`creation`::
+Creation time of the API key in milliseconds.
+
+`expiration`::
+Expiration time of the API key in milliseconds.
+
+`invalidated`::
+Indicates whether the API key is invalidated. If `true`, the key is invalidated.
+Defaults to `false`.
+
+`username`::
+Username of the API key owner.
+
+`realm`::
+Realm name of the API key owner.
+
+`metadata`::
+Metadata field associated with the API key, such as `metadata.my_field`. Because
+metadata is stored as a <<flattened,flattened>> field type, all fields act like
+`keyword` fields when querying and sorting.
+====
+
+include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=from]
++
+By default, you cannot page through more than 10,000 hits using the `from` and
+`size` parameters. To page through more hits, use the
+<<search-after,`search_after`>> parameter.
+
+`size`::
+(Optional, integer) The number of hits to return. Must not be negative and defaults to `10`.
++
+By default, you cannot page through more than 10,000 hits using the `from` and
+`size` parameters. To page through more hits, use the
+<<search-after,`search_after`>> parameter.
+
+`sort`::
+(Optional, object) <<sort-search-results,Sort definition>>. Other than `id`,
+all public fields of an API key are eligible for sorting. In addition, sort can
+also be applied to the `_doc` field to sort by index order.
+
+`search_after`::
+(Optional, array) <<search-after,Search after>> definition.
+
+
+[[security-api-query-api-key-response-body]]
+==== {api-response-body-title}
+
+This API returns the following top level fields:
+
+`total`::
+The total number of API keys found.
+
+`count`::
+The number of API keys returned in the response.
+
+`api_keys`::
+A list of API key information.
+
+[[security-api-query-api-key-example]]
+==== {api-examples-title}
+
+The following request lists all API keys, assuming you have the
+`manage_api_key` privilege:
+
+[source,console]
+----
+GET /_security/_query/api_key
+----
+
+A successful call returns a JSON structure that contains the information
+retrieved from one or more API keys:
+
+[source,js]
+----
+{
+  "total": 3,
+  "count": 3,
+  "api_keys": [ <1>
+    {
+      "id": "nkvrGXsB8w290t56q3Rg",
+      "name": "my-api-key-1",
+      "creation": 1628227480421,
+      "expiration": 1629091480421,
+      "invalidated": false,
+      "username": "elastic",
+      "realm": "reserved",
+      "metadata": {
+        "letter": "a"
+      }
+    },
+    {
+      "id": "oEvrGXsB8w290t5683TI",
+      "name": "my-api-key-2",
+      "creation": 1628227498953,
+      "expiration": 1628313898953,
+      "invalidated": false,
+      "username": "elastic",
+      "realm": "reserved",
+      "metadata": {
+        "letter": "b"
+      }
+    }
+  ]
+}
+----
+// NOTCONSOLE
+
+<1> The list of API keys that were retrieved for this request
+
+If you create an API key with the following details:
+
+[source,console]
+----
+POST /_security/api_key
+{
+  "name": "application-key-1",
+  "metadata": { "application": "my-application"}
+}
+----
+
+A successful call returns a JSON structure that provides
+API key information. For example:
+
+[source,console-result]
+----
+{
+  "id": "VuaCfGcBCdbkQm-e5aOx",
+  "name": "application-key-1",
+  "api_key": "ui2lp2axTNmsyakw9tvNnw"
+}
+----
+// TESTRESPONSE[s/VuaCfGcBCdbkQm-e5aOx/$body.id/]
+// TESTRESPONSE[s/ui2lp2axTNmsyakw9tvNnw/$body.api_key/]
+
+Use the information from the response to retrieve the API key by ID:
+
+[source,console]
+----
+GET /_security/_query/api_key
+{
+  "query": {
+    "ids": {
+      "values": [
+        "VuaCfGcBCdbkQm-e5aOx"
+      ]
+    }
+  }
+}
+----
+// TEST[s/VuaCfGcBCdbkQm-e5aOx/$body.id/]
+// TEST[continued]
+
+You can also retrieve the API key by name:
+
+[source,console]
+----
+GET /_security/_query/api_key
+{
+  "query": {
+    "term": {
+      "name": {
+        "value": "application-key-1"
+      }
+    }
+  }
+}
+----
+// TEST[continued]
+
+Use a `bool` query to issue complex logical conditions and use
+`from`, `size`, `sort` to help paginate the result:
+
+[source,js]
+----
+{
+  "query": {
+    "bool": {
+      "must": [
+        {
+          "prefix": {
+            "name": "app1-key-" <1>
+          }
+        },
+        {
+          "term": {
+            "invalidated": "false" <2>
+          }
+        }
+      ],
+      "must_not": [
+        {
+          "term": {
+            "name": "app1-key-01" <3>
+          }
+        }
+      ],
+      "filter": [
+        {
+          "wildcard": {
+            "username": "org-*-user" <4>
+          }
+        },
+        {
+          "term": {
+            "metadata.environment": "production" <5>
+          }
+        }
+      ]
+    }
+  },
+  "from": 20, <6>
+  "size": 10, <7>
+  "sort": [ <8>
+    { "creation": { "order": "desc", "format": "date_time" } },
+    "name"
+  ]
+}
+----
+// NOTCONSOLE
+
+<1> The API key name must begin with `app1-key-`
+<2> The API key must still be valid
+<3> The API key name must not be `app1-key-01`
+<4> The API key must be owned by a username of the <<query-dsl-wildcard-query,wildcard>> pattern `org-*-user`
+<5> The API key must have the metadata field `environment` that has the value of `production`
+<6> The offset to begin the search result is the 20th (zero-based index) API key
+<7> The page size of the response is 10 API keys
+<8> The result is first sorted by `creation` date in descending order, then by name in ascending order
+
+The response contains a list of matched API keys along with their sort values:
+
+[source,js]
+----
+{
+  "total": 100,
+  "count": 10,
+  "api_keys": [
+    {
+      "id": "CLXgVnsBOGkf8IyjcXU7",
+      "name": "app1-key-79",
+      "creation": 1629250154811,
+      "invalidated": false,
+      "username": "org-admin-user",
+      "realm": "native1",
+      "metadata": {
+        "environment": "production"
+      },
+      "_sort": [
+        "2021-08-18T01:29:14.811Z",  <1>
+        "app1-key-79"  <2>
+      ]
+    },
+    {
+      "id": "BrXgVnsBOGkf8IyjbXVB",
+      "name": "app1-key-78",
+      "creation": 1629250153794,
+      "invalidated": false,
+      "username": "org-admin-user",
+      "realm": "native1",
+      "metadata": {
+        "environment": "production"
+      },
+      "_sort": [
+        "2021-08-18T01:29:13.794Z",
+        "app1-key-78"
+      ]
+    },
+    ...
+  ]
+}
+----
+// NOTCONSOLE
+
+<1> The first sort value is creation time, which is displayed in `date_time` <<mapping-date-format,format>> as defined in the request
+<2> The second sort value is the API key name