chore: refining logging related to execution errors that may be retried

this addressed operator-framework#409 where the log contains verbose error messages
related to status update conflicts

Author: shawkins

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/DefaultEventHandler.java

@@ -162,7 +162,7 @@ private void handleRetryOnException(ExecutionScope executionScope) {
     }
     Optional<Long> nextDelay = execution.nextDelay();
 
-    nextDelay.ifPresent(
+    nextDelay.ifPresentOrElse(
         delay -> {
           log.debug(
               "Scheduling timer event for retry with delay:{} for resource: {}",
@@ -171,6 +171,9 @@ private void handleRetryOnException(ExecutionScope executionScope) {
           eventSourceManager
               .getRetryTimerEventSource()
               .scheduleOnce(executionScope.getCustomResource(), delay);
+        },
+        () -> {
+          log.error("Exhausted retries for {}", executionScope);
         });
   }
 

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/EventDispatcher.java

@@ -6,6 +6,7 @@
 
 import io.fabric8.kubernetes.api.model.KubernetesResourceList;
 import io.fabric8.kubernetes.client.CustomResource;
+import io.fabric8.kubernetes.client.KubernetesClientException;
 import io.fabric8.kubernetes.client.dsl.MixedOperation;
 import io.fabric8.kubernetes.client.dsl.Resource;
 import io.javaoperatorsdk.operator.api.Context;
@@ -53,6 +54,13 @@ public void setEventSourceManager(EventSourceManager eventSourceManager) {
   public PostExecutionControl handleExecution(ExecutionScope<R> executionScope) {
     try {
       return handleDispatch(executionScope);
+    } catch (KubernetesClientException e) {
+      log.info(
+          "Kubernetes exception {} {} during event processing, {} failed",
+          e.getCode(),
+          e.getMessage(),
+          executionScope);
+      return PostExecutionControl.exceptionDuringExecution(e);
     } catch (RuntimeException e) {
       log.error("Error during event processing {} failed.", executionScope, e);
       return PostExecutionControl.exceptionDuringExecution(e);