AMBARI-13296. Credential Resource API should return an empty list rather than a 404 error (rlevas)

ambari-server/src/main/java/org/apache/ambari/server/controller/internal/CredentialResourceProvider.java

@@ -119,6 +119,7 @@ public class CredentialResourceProvider extends AbstractControllerResourceProvid
 
     Set<String> requestedIds = getRequestPropertyIds(request, predicate);
     Set<Resource> resources = new HashSet<Resource>();
+    boolean sendNotFoundErrorIfEmpty = false;
 
     for (Map<String, Object> propertyMap : getPropertyMaps(predicate)) {
       String clusterName = (String) propertyMap.get(CREDENTIAL_CLUSTER_NAME_PROPERTY_ID);
@@ -133,6 +134,14 @@ public class CredentialResourceProvider extends AbstractControllerResourceProvid
           if (credentialStoreService.containsCredential(clusterName, alias)) {
             resources.add(toResource(clusterName, alias, credentialStoreService.getCredentialStoreType(clusterName, alias), requestedIds));
           }
+          else {
+            // Only throw a NoSuchResourceException if a specific item is being requested and it
+            // wasn't found. If multiple resources are queried, one or may not exist and this
+            // sendNotFoundErrorIfEmpty will be set to true.  However if at least one resource is
+            // found, the resources Set will not be empty and NoSuchResourceException will not be
+            // thrown
+            sendNotFoundErrorIfEmpty = true;
+          }
         } catch (AmbariException e) {
           throw new SystemException(e.getLocalizedMessage(), e);
         }
@@ -150,7 +159,7 @@ public class CredentialResourceProvider extends AbstractControllerResourceProvid
       }
     }
 
-    if ((predicate != null) && resources.isEmpty()) {
+    if (sendNotFoundErrorIfEmpty && resources.isEmpty()) {
       throw new NoSuchResourceException("The requested resource doesn't exist: Credential not found, " + predicate);
     }
 

ambari-server/src/test/java/org/apache/ambari/server/controller/internal/CredentialResourceProviderTest.java

@@ -451,6 +451,38 @@ public class CredentialResourceProviderTest {
 
     verify(request, factory, managementController);
   }
+  @Test
+  public void testGetResources_WithOutPredicateNoResults() throws Exception {
+
+    AmbariManagementController managementController = createMock(AmbariManagementController.class);
+    Request request = createMock(Request.class);
+
+    CredentialResourceProvider credentialResourceProvider = new CredentialResourceProvider(managementController);
+    injector.injectMembers(credentialResourceProvider);
+
+    // Get resources request
+    expect(request.getPropertyIds()).andReturn(null).once();
+
+    ResourceProviderFactory factory = createMock(ResourceProviderFactory.class);
+    expect(factory.getCredentialResourceProvider(anyObject(AmbariManagementController.class))).andReturn(credentialResourceProvider);
+
+    replay(request, factory, managementController);
+    // end expectations
+
+    AbstractControllerResourceProvider.init(factory);
+
+    ResourceProvider provider = AbstractControllerResourceProvider.getResourceProvider(
+        Resource.Type.Credential,
+        PropertyHelper.getPropertyIds(Resource.Type.Credential),
+        PropertyHelper.getKeyPropertyIds(Resource.Type.Credential),
+        managementController);
+
+
+    Set<Resource> results = provider.getResources(request, null);
+    Assert.assertTrue(results.isEmpty());
+
+    verify(request, factory, managementController);
+  }
 
   @Test
   public void testUpdateResources() throws Exception {