bug fix to requested resource does not exist handling

bug fix to requested resource does not exist handling. we need to keep watch active for when resource is finally created so we can notify client.

envoyproxy#219

cache/src/main/java/io/envoyproxy/controlplane/cache/SimpleCache.java

@@ -377,10 +377,9 @@ protected void respondWithSpecificOrder(T group,
  version);
  }
 
- respond(watch, snapshot, group);
-
- // Discard the watch. A new watch will be created for future snapshots once envoy ACKs the response.
- return true;
+ // If we respond with an actual message, we can proceed to discard the watch. 
+ // A new watch will be created for future snapshots once envoy ACKs the response.
+ return respond(watch, snapshot, group);
  }
 
  // Do not discard the watch. The request version is the same as the snapshot version, so we wait to respond.

cache/src/test/java/io/envoyproxy/controlplane/cache/v3/SimpleCacheTest.java

@@ -476,6 +476,64 @@ public void watchIsLeftOpenIfNotRespondedImmediately() {
  assertThatWatchIsOpenWithNoResponses(new WatchAndTracker(watch, responseTracker));
  }
 
+ @Test
+ public void watchIsLeftOpenIfNotRespondedImmediatelyAndThroughSubsequentSetEmptySnapshots() {
+ SimpleCache<String> cache = new SimpleCache<>(new SingleNodeGroup());
+ cache.setSnapshot(SingleNodeGroup.GROUP, Snapshot.create(
+ ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), VERSION1));
+
+ ResponseTracker responseTracker = new ResponseTracker();
+ Watch watch = cache.createWatch(
+ true,
+ XdsRequest.create(DiscoveryRequest.newBuilder()
+ .setNode(Node.getDefaultInstance())
+ .setTypeUrl(ROUTE_TYPE_URL)
+ .addAllResourceNames(Collections.singleton(ROUTE_NAME))
+ .build()),
+ Collections.singleton(ROUTE_NAME),
+ responseTracker);
+
+ assertThatWatchIsOpenWithNoResponses(new WatchAndTracker(watch, responseTracker));
+ assertThat(cache.statusInfo(SingleNodeGroup.GROUP).numWatches()).isEqualTo(1);
+
+ cache.setSnapshot(SingleNodeGroup.GROUP, Snapshot.create(
+ ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), VERSION2));
+
+ assertThatWatchIsOpenWithNoResponses(new WatchAndTracker(watch, responseTracker));
+ assertThat(cache.statusInfo(SingleNodeGroup.GROUP).numWatches()).isEqualTo(1);
+ }
+
+ @Test
+ public void watchIsLeftOpenIfNotRespondedImmediatelyAndLaterSetSnapshotSendsUpdate() {
+ SimpleCache<String> cache = new SimpleCache<>(new SingleNodeGroup());
+ cache.setSnapshot(SingleNodeGroup.GROUP, Snapshot.create(
+ ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), VERSION1));
+
+ ResponseTracker responseTracker = new ResponseTracker();
+ Watch watch = cache.createWatch(
+ true,
+ XdsRequest.create(DiscoveryRequest.newBuilder()
+ .setNode(Node.getDefaultInstance())
+ .setTypeUrl(ROUTE_TYPE_URL)
+ .addAllResourceNames(SNAPSHOT1.resources(ROUTE_TYPE_URL).keySet())
+ .build()),
+ Collections.emptySet(),
+ responseTracker);
+
+ assertThatWatchIsOpenWithNoResponses(new WatchAndTracker(watch, responseTracker));
+ assertThat(cache.statusInfo(SingleNodeGroup.GROUP).numWatches()).isEqualTo(1);
+
+ cache.setSnapshot(SingleNodeGroup.GROUP, Snapshot.create(
+ ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), ImmutableList.of(), VERSION2));
+
+ assertThatWatchIsOpenWithNoResponses(new WatchAndTracker(watch, responseTracker));
+ assertThat(cache.statusInfo(SingleNodeGroup.GROUP).numWatches()).isEqualTo(1);
+
+ cache.setSnapshot(SingleNodeGroup.GROUP, SNAPSHOT1);
+
+ assertThatWatchReceivesSnapshot(new WatchAndTracker(watch, responseTracker), SNAPSHOT1);
+ }
+
  @Test
  public void getSnapshot() {
  SimpleCache<String> cache = new SimpleCache<>(new SingleNodeGroup());