add support for is_write_index in put-alias body parsing (#31674)

* add support for is_write_index in put-alias body parsing

The Rest Put-Alias Action does separate parsing of the alias body
to construct the IndicesAliasesRequest. This extra parsing
was missed in #30703.

* test flag was not just ignored by the parser

rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_alias/10_basic.yml

@@ -59,3 +59,27 @@
  indices.put_alias:
  index: test_index
  name: foo
+
+---
+"Can set is_write_index":
+
+ - skip:
+ version: " - 6.3.99"
+ reason: "is_write_index is only available from 6.4.0 on"
+
+ - do:
+ indices.create:
+ index: test_index
+
+ - do:
+ indices.put_alias:
+ index: test_index
+ name: test_alias
+ body:
+ is_write_index: true
+
+ - do:
+ indices.get_alias:
+ index: test_index
+ name: test_alias
+ - match: {test_index.aliases.test_alias: { 'is_write_index': true }}

server/src/main/java/org/elasticsearch/rest/action/admin/indices/RestIndexPutAliasAction.java

@@ -66,6 +66,7 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
  String routing = null;
  String indexRouting = null;
  String searchRouting = null;
+ Boolean writeIndex = null;
 
  if (request.hasContent()) {
  try (XContentParser parser = request.contentParser()) {
@@ -90,6 +91,8 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
  } else if ("searchRouting".equals(currentFieldName)
  || "search-routing".equals(currentFieldName) || "search_routing".equals(currentFieldName)) {
  searchRouting = parser.textOrNull();
+ } else if ("is_write_index".equals(currentFieldName)) {
+ writeIndex = parser.booleanValue();
  }
  } else if (token == XContentParser.Token.START_OBJECT) {
  if ("filter".equals(currentFieldName)) {
@@ -117,6 +120,9 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
  if (filter != null) {
  aliasAction.filter(filter);
  }
+ if (writeIndex != null) {
+ aliasAction.writeIndex(writeIndex);
+ }
  indicesAliasesRequest.addAliasAction(aliasAction);
  return channel -> client.admin().indices().aliases(indicesAliasesRequest, new RestToXContentListener<>(channel));
  }