perf: avoid redundant work on informer event paths (#3545)

- Mappers#fromMetadata resolved the primary GroupVersionKind on every
  secondary event, although it only depends on the primary type. Hoist it out
  of the lambda and compare the encoded string before falling back to parsing
  the annotation value.
- Mappers.SecondaryToPrimaryFromDefaultAnnotation built a whole new mapper on
  every invocation; hold a single delegate instead. The primaryResourceType
  field becomes unused and is dropped.
- InformerEventSource#start walked the entire informer cache to seed the
  primary-to-secondary index even when that index is the no-op implementation
  (i.e. whenever a primaryToSecondaryMapper is configured), which is pure
  startup latency proportional to the number of cached secondaries.
- ExternalResourceCachingEventSource#getSecondaryResources looked the primary
  up in the cache a second time although the value was already in a local.
- PerResourcePollingEventSource#getAndCacheResource derived the same
  ResourceID twice in adjacent statements.

Author: csviri

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/source/informer/InformerEventSource.java

@@ -177,7 +177,9 @@ public synchronized void start() {
     super.start();
     // this makes sure that on first reconciliation all resources are
     // present on the index
-    manager().list().forEach(r -> primaryToSecondaryIndex.onAddOrUpdate(r, null));
+    if (useSecondaryToPrimaryIndex()) {
+      manager().list().forEach(r -> primaryToSecondaryIndex.onAddOrUpdate(r, null));
+    }
   }
 
   @SuppressWarnings("unchecked")

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/source/informer/Mappers.java

@@ -124,6 +124,8 @@ private static <T extends HasMetadata> SecondaryToPrimaryMapper<T> fromMetadata(
       String typeKey,
       Class<? extends HasMetadata> primaryResourceType,
       boolean isLabel) {
+    final var expectedGvk = GroupVersionKind.gvkFor(primaryResourceType);
+    final var expectedGvkString = expectedGvk.toGVKString();
     return resource -> {
       final var metadata = resource.getMetadata();
       if (metadata == null) {
@@ -143,8 +145,8 @@ private static <T extends HasMetadata> SecondaryToPrimaryMapper<T> fromMetadata(
         String gvkSimple = map.get(typeKey);
 
         if (gvkSimple != null
-            && !GroupVersionKind.fromString(gvkSimple)
-                .equals(GroupVersionKind.gvkFor(primaryResourceType))) {
+            && !expectedGvkString.equals(gvkSimple)
+            && !GroupVersionKind.fromString(gvkSimple).equals(expectedGvk)) {
           return Set.of();
         }
 
@@ -183,24 +185,24 @@ SecondaryToPrimaryMapper<T> fromOwnerType(Class<OWNER> clazz) {
       }
       return owners.stream()
           .filter(it -> kind.equals(it.getKind()))
-          .map(it -> new ResourceID(it.getName(), resource.getMetadata().getNamespace()))
+          .map(it -> ResourceID.fromOwnerReference(resource, it, false))
           .collect(Collectors.toSet());
     };
   }
 
   public static class SecondaryToPrimaryFromDefaultAnnotation
       implements SecondaryToPrimaryMapper<HasMetadata> {
 
-    private final Class<? extends HasMetadata> primaryResourceType;
+    private final SecondaryToPrimaryMapper<HasMetadata> delegate;
 
     public SecondaryToPrimaryFromDefaultAnnotation(
         Class<? extends HasMetadata> primaryResourceType) {
-      this.primaryResourceType = primaryResourceType;
+      this.delegate = Mappers.fromDefaultAnnotations(primaryResourceType);
     }
 
     @Override
     public Set<ResourceID> toPrimaryResourceIDs(HasMetadata resource) {
-      return Mappers.fromDefaultAnnotations(primaryResourceType).toPrimaryResourceIDs(resource);
+      return delegate.toPrimaryResourceIDs(resource);
     }
   }
 }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/source/polling/PerResourcePollingEventSource.java

@@ -75,8 +75,9 @@ public PerResourcePollingEventSource(
 
   private Set<R> getAndCacheResource(P primary, boolean fromGetter) {
     var values = resourceFetcher.fetchResources(primary);
-    handleResources(ResourceID.fromResource(primary), values, !fromGetter);
-    fetchedForPrimaries.add(ResourceID.fromResource(primary));
+    var primaryID = ResourceID.fromResource(primary);
+    handleResources(primaryID, values, !fromGetter);
+    fetchedForPrimaries.add(primaryID);
     return values;
   }