The kube resolver should set the endpoints when the subsets json structure is not present.

Motivation:

The kube resolver sets the list of endpoints (pods) from the subsets member of the endpoints json object.

When the service does not have any pods, the subsets member is absent and causes an NPE downstream in the resolver assuming the endpoints list is never null.

Changes:

Always set the list of endpoints to consistently populate the list.

Author: vietj

src/main/java/io/vertx/serviceresolver/kube/impl/KubeServiceState.java

@@ -98,8 +98,8 @@ void handleEndpoints(JsonObject item) {
     String name = metadata.getString("name");
     if (this.name.equals(name)) {
       JsonArray subsets = item.getJsonArray("subsets");
+      EndpointBuilder<B, SocketAddress> builder = endpointsBuilder;
       if (subsets != null) {
-        EndpointBuilder<B, SocketAddress> builder = endpointsBuilder;
         for (int j = 0;j < subsets.size();j++) {
           List<String> podIps = new ArrayList<>();
           JsonObject subset = subsets.getJsonObject(j);
@@ -119,8 +119,8 @@ void handleEndpoints(JsonObject item) {
             }
           }
         }
-        this.endpoints.set(builder.build());
       }
+      this.endpoints.set(builder.build());
     }
   }
 }

src/test/java/io/vertx/tests/kube/KubeServiceResolverMockTest.java

@@ -16,6 +16,9 @@
 import java.net.InetAddress;
 import java.util.*;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
 public class KubeServiceResolverMockTest extends KubeServiceResolverTestBase {
 
   @Rule

src/test/java/io/vertx/tests/kube/KubeServiceResolverTestBase.java

@@ -9,8 +9,12 @@
 import org.junit.Ignore;
 import org.junit.Test;
 
+import java.util.Collections;
 import java.util.List;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
 public abstract class KubeServiceResolverTestBase extends ServiceResolverTestBase {
 
   protected KubernetesMocking kubernetesMocking;
@@ -104,7 +108,19 @@ public void testDeletePod(TestContext should) throws Exception {
     }
   }
 
-/*
+  @Test
+  public void testEmptyPods() throws Exception {
+    String serviceName = "svc";
+    kubernetesMocking.buildAndRegisterKubernetesService(serviceName, kubernetesMocking.defaultNamespace(), KubeOp.CREATE, Collections.emptyList());
+    try {
+      get(ServiceAddress.of("svc"));
+      fail();
+    } catch (IllegalStateException e) {
+      assertEquals("No results for svc", e.getMessage());
+    }
+  }
+
+  /*
   @Test
   public void testDispose(TestContext should) throws Exception {
     Handler<HttpServerRequest> server = req -> {