Add check for empty addresses and if not there disable ipV6. (grpc#10848)

* Add check for empty addresses and if not there dissable ipV6.

Author: larry-safran

googleapis/src/main/java/io/grpc/googleapis/GoogleCloudToProdNameResolver.java

@@ -34,6 +34,7 @@
 import io.grpc.internal.SharedResourceHolder;
 import io.grpc.internal.SharedResourceHolder.Resource;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.net.HttpURLConnection;
@@ -43,11 +44,15 @@
 import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.Executor;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 /**
  * CloudToProd version of {@link NameResolver}.
  */
 final class GoogleCloudToProdNameResolver extends NameResolver {
+  private static final Logger logger =
+      Logger.getLogger(GoogleCloudToProdNameResolver.class.getName());
 
   @VisibleForTesting
   static final String METADATA_URL_ZONE =
@@ -142,13 +147,20 @@ private void resolve() {
     if (resolving || shutdown || delegate == null) {
       return;
     }
+
     resolving = true;
+    if (logger.isLoggable(Level.FINE)) {
+      logger.fine("resolve with schemaOverride = " + schemeOverride);
+    }
+
     if (schemeOverride.equals("dns")) {
       delegate.start(listener);
       succeeded = true;
       resolving = false;
       return;
     }
+
+    // Since not dns, we must be using xds
     if (executor == null) {
       executor = SharedResourceHolder.get(executorResource);
     }
@@ -267,7 +279,13 @@ private boolean queryIpv6SupportMetadata(String url) throws IOException {
     HttpURLConnection con = null;
     try {
       con = httpConnectionProvider.createConnection(url);
-      return con.getResponseCode() == 200;
+      if (con.getResponseCode() != 200 ) {
+        return false;
+      }
+      InputStream inputStream = con.getInputStream();
+      int c;
+      return (inputStream != null
+          && (c = inputStream.read()) != -1 && !Character.isWhitespace(c));
     } finally {
       if (con != null) {
         con.disconnect();

googleapis/src/test/java/io/grpc/googleapis/GoogleCloudToProdNameResolverTest.java

@@ -125,6 +125,10 @@ public void tearDown() {
   }
 
   private void createResolver() {
+    createResolver("1:1:1");
+  }
+
+  private void createResolver(String responseToIpV6) {
     HttpConnectionProvider httpConnections = new HttpConnectionProvider() {
       @Override
       public HttpURLConnection createConnection(String url) throws IOException {
@@ -135,6 +139,10 @@ public HttpURLConnection createConnection(String url) throws IOException {
               new ByteArrayInputStream(("/" + ZONE).getBytes(StandardCharsets.UTF_8)));
           return con;
         } else if (url.equals(GoogleCloudToProdNameResolver.METADATA_URL_SUPPORT_IPV6)) {
+          if (responseToIpV6 != null) {
+            when(con.getInputStream()).thenReturn(
+                new ByteArrayInputStream(responseToIpV6.getBytes(StandardCharsets.UTF_8)));
+          }
           return con;
         }
         throw new AssertionError("Unknown http query");
@@ -147,7 +155,7 @@ public HttpURLConnection createConnection(String url) throws IOException {
   }
 
   @Test
-  public void notOnGcpDelegateToDns() {
+  public void notOnGcp_DelegateToDns() {
     GoogleCloudToProdNameResolver.isOnGcp = false;
     createResolver();
     resolver.start(mockListener);
@@ -156,7 +164,7 @@ public void notOnGcpDelegateToDns() {
   }
 
   @Test
-  public void hasProvidedBootstrapDelegateToDns() {
+  public void hasProvidedBootstrap_DelegateToDns() {
     GoogleCloudToProdNameResolver.isOnGcp = true;
     GoogleCloudToProdNameResolver.xdsBootstrapProvided = true;
     GoogleCloudToProdNameResolver.enableFederation = false;
@@ -168,7 +176,7 @@ public void hasProvidedBootstrapDelegateToDns() {
 
   @SuppressWarnings("unchecked")
   @Test
-  public void onGcpAndNoProvidedBootstrapDelegateToXds() {
+  public void onGcpAndNoProvidedBootstrap_DelegateToXds() {
     GoogleCloudToProdNameResolver.isOnGcp = true;
     GoogleCloudToProdNameResolver.xdsBootstrapProvided = false;
     createResolver();
@@ -196,7 +204,51 @@ public void onGcpAndNoProvidedBootstrapDelegateToXds() {
 
   @SuppressWarnings("unchecked")
   @Test
-  public void onGcpAndNoProvidedBootstrapAndFederationEnabledDelegateToXds() {
+  public void onGcpAndNoProvidedBootstrap_DelegateToXds_noIpV6() {
+    GoogleCloudToProdNameResolver.isOnGcp = true;
+    GoogleCloudToProdNameResolver.xdsBootstrapProvided = false;
+    createResolver(null);
+    resolver.start(mockListener);
+    fakeExecutor.runDueTasks();
+    assertThat(delegatedResolver.keySet()).containsExactly("xds");
+    verify(Iterables.getOnlyElement(delegatedResolver.values())).start(mockListener);
+    Map<String, ?> bootstrap = fakeBootstrapSetter.bootstrapRef.get();
+    Map<String, ?> node = (Map<String, ?>) bootstrap.get("node");
+    assertThat(node).containsExactly(
+        "id", "C2P-991614323",
+        "locality", ImmutableMap.of("zone", ZONE));
+    Map<String, ?> server = Iterables.getOnlyElement(
+        (List<Map<String, ?>>) bootstrap.get("xds_servers"));
+    assertThat(server).containsExactly(
+        "server_uri", "directpath-pa.googleapis.com",
+        "channel_creds", ImmutableList.of(ImmutableMap.of("type", "google_default")),
+        "server_features", ImmutableList.of("xds_v3", "ignore_resource_deletion"));
+    Map<String, ?> authorities = (Map<String, ?>) bootstrap.get("authorities");
+    assertThat(authorities).containsExactly(
+        "traffic-director-c2p.xds.googleapis.com",
+        ImmutableMap.of("xds_servers", ImmutableList.of(server)));
+  }
+
+  @SuppressWarnings("unchecked")
+  @Test
+  public void emptyResolverMeetadataValue() {
+    GoogleCloudToProdNameResolver.isOnGcp = true;
+    GoogleCloudToProdNameResolver.xdsBootstrapProvided = false;
+    createResolver("");
+    resolver.start(mockListener);
+    fakeExecutor.runDueTasks();
+    assertThat(delegatedResolver.keySet()).containsExactly("xds");
+    verify(Iterables.getOnlyElement(delegatedResolver.values())).start(mockListener);
+    Map<String, ?> bootstrap = fakeBootstrapSetter.bootstrapRef.get();
+    Map<String, ?> node = (Map<String, ?>) bootstrap.get("node");
+    assertThat(node).containsExactly(
+        "id", "C2P-991614323",
+        "locality", ImmutableMap.of("zone", ZONE));
+  }
+
+  @SuppressWarnings("unchecked")
+  @Test
+  public void onGcpAndNoProvidedBootstrapAndFederationEnabled_DelegateToXds() {
     GoogleCloudToProdNameResolver.isOnGcp = true;
     GoogleCloudToProdNameResolver.xdsBootstrapProvided = false;
     GoogleCloudToProdNameResolver.enableFederation = true;
@@ -226,7 +278,7 @@ public void onGcpAndNoProvidedBootstrapAndFederationEnabledDelegateToXds() {
 
   @SuppressWarnings("unchecked")
   @Test
-  public void onGcpAndProvidedBootstrapAndFederationEnabledDontDelegateToXds() {
+  public void onGcpAndProvidedBootstrapAndFederationEnabled_DontDelegateToXds() {
     GoogleCloudToProdNameResolver.isOnGcp = true;
     GoogleCloudToProdNameResolver.xdsBootstrapProvided = true;
     GoogleCloudToProdNameResolver.enableFederation = true;