PUT /_aliases should accept a numeric routing value

Also added REST tests for setting index/search/routing
via the PUT /_aliases endpoint

Fixes #5465

rest-api-spec/test/indices.update_aliases/20_routing.yaml

@@ -0,0 +1,135 @@
+setup:
+  - do:
+      indices.create:
+        index: test_index
+
+---
+"Routing":
+
+  - do:
+      indices.update_aliases:
+        body:
+          actions:
+            - add:
+                index: test_index
+                alias: test_alias
+                routing: routing
+
+  - do:
+      indices.get_aliases:
+        index: test_index
+
+  - match: {test_index.aliases.test_alias: {'index_routing': 'routing', 'search_routing': 'routing'}}
+
+---
+"Index Routing":
+
+  - do:
+      indices.update_aliases:
+        body:
+          actions:
+            - add:
+                index: test_index
+                alias: test_alias
+                index_routing: index_routing
+
+  - do:
+      indices.get_aliases:
+        index: test_index
+
+  - match: {test_index.aliases.test_alias: {'index_routing': 'index_routing'}}
+
+---
+"Search Routing":
+
+  - do:
+      indices.update_aliases:
+        body:
+          actions:
+            - add:
+                index: test_index
+                alias: test_alias
+                search_routing: search_routing
+
+  - do:
+      indices.get_aliases:
+        index: test_index
+
+  - match: {test_index.aliases.test_alias: {'search_routing': 'search_routing'}}
+
+---
+"Index, Default Routing":
+
+  - do:
+      indices.update_aliases:
+        body:
+          actions:
+            - add:
+                index: test_index
+                alias: test_alias
+                index_routing: index_routing
+                routing: routing
+
+  - do:
+      indices.get_aliases:
+        index: test_index
+
+  - match: {test_index.aliases.test_alias: {'index_routing': 'index_routing', 'search_routing': 'routing'}}
+
+---
+"Search, Default Routing":
+
+  - do:
+      indices.update_aliases:
+        body:
+          actions:
+            - add:
+                index: test_index
+                alias: test_alias
+                search_routing: search_routing
+                routing: routing
+
+  - do:
+      indices.get_aliases:
+        index: test_index
+
+  - match: {test_index.aliases.test_alias: {'index_routing': 'routing', 'search_routing': 'search_routing'}}
+
+---
+"Index, Search, Default Routing":
+
+  - do:
+      indices.update_aliases:
+        body:
+          actions:
+            - add:
+                index: test_index
+                alias: test_alias
+                index_routing: index_routing
+                search_routing: search_routing
+                routing: routing
+
+  - do:
+      indices.get_aliases:
+        index: test_index
+
+  - match: {test_index.aliases.test_alias: {'index_routing': 'index_routing', 'search_routing': 'search_routing'}}
+
+---
+"Numeric Routing":
+
+  - do:
+      indices.update_aliases:
+        body:
+          actions:
+            - add:
+                index: test_index
+                alias: test_alias
+                routing: 5
+
+  - do:
+      indices.get_aliases:
+        index: test_index
+
+  - match: {test_index.aliases.test_alias: {'index_routing': '5', 'search_routing': '5'}}
+

src/main/java/org/elasticsearch/rest/action/admin/indices/alias/RestIndicesAliasesAction.java

@@ -92,7 +92,7 @@ public void handleRequest(final RestRequest request, final RestChannel channel)
                             while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
                                 if (token == XContentParser.Token.FIELD_NAME) {
                                     currentFieldName = parser.currentName();
-                                } else if (token == XContentParser.Token.VALUE_STRING) {
+                                } else if (token.isValue()) {
                                     if ("index".equals(currentFieldName)) {
                                         index = parser.text();
                                     } else if ("alias".equals(currentFieldName)) {