Handle multiple aliases in _cat/aliases api

core/src/main/java/org/elasticsearch/rest/action/cat/RestAliasAction.java

@@ -46,7 +46,7 @@ public RestAliasAction(Settings settings, RestController controller) {
     @Override
     protected RestChannelConsumer doCatRequest(final RestRequest request, final NodeClient client) {
         final GetAliasesRequest getAliasesRequest = request.hasParam("alias") ?
-                new GetAliasesRequest(request.param("alias")) :
+                new GetAliasesRequest(request.param("alias").split(",")) :
                 new GetAliasesRequest();
         getAliasesRequest.local(request.paramAsBoolean("local", getAliasesRequest.local()));
 

docs/reference/cat/alias.asciidoc

@@ -54,5 +54,6 @@ alias4 test1 -      2            1,2
 The output shows that `alias2` has configured a filter, and specific routing
 configurations in `alias3` and `alias4`.
 
-If you only want to get information about a single alias, you can specify
-the alias in the URL, for example `/_cat/aliases/alias1`.
+If you only want to get information about specific aliases, you can specify 
+the aliases in comma-delimited format as a URL parameter, e.g., 
+/_cat/aliases/aliases/alias1,alias2.

rest-api-spec/src/main/resources/rest-api-spec/test/cat.aliases/10_basic.yaml

@@ -126,6 +126,48 @@
   - match:
       $body: / (^|\n)test_2 .+ \n/
 
+---
+"Multiple alias names":
+
+  - do:
+        indices.create:
+            index: test
+
+  - do:
+        indices.create:
+            index: test2
+  - do:
+        indices.create:
+            index: test3
+
+  - do:
+        indices.put_alias:
+            index: test
+            name: foo
+
+  - do:
+        indices.put_alias:
+            index: test2
+            name: bar
+  - do:
+        indices.put_alias:
+            index: test3
+            name: baz
+
+  - do:
+        cat.aliases:
+            name: foo,bar
+
+  - match:
+      $body: /(^|\n)foo\s+test /
+
+  - match:
+      $body: /(^|\n)bar\s+test2 /
+
+  - match:
+      $body: /(^|\n)[^bar\s+test3] /
+
+
 ---
 "Column headers":