Protect against streaming null collection of container ports

Author: rjeberhard

common/src/main/java/oracle/kubernetes/common/utils/CommonUtils.java

@@ -1,12 +1,14 @@
-// Copyright (c) 2022, Oracle and/or its affiliates.
+// Copyright (c) 2022, 2023, Oracle and/or its affiliates.
 // Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl.
 
 package oracle.kubernetes.common.utils;
 
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.util.Collection;
 import java.util.Optional;
+import java.util.stream.Stream;
 
 import oracle.kubernetes.common.CommonConstants;
 
@@ -21,6 +23,16 @@ private CommonUtils() {
     //not called
   }
 
+  /**
+   * Stream a collection with protection for null collections.
+   * @param <T> Type
+   * @param collection Collection
+   * @return Stream
+   */
+  public static <T> Stream<T> stream(Collection<T> collection) {
+    return Optional.ofNullable(collection).stream().flatMap(Collection::stream);
+  }
+
   /**
    * Returns the image pull policy to use by default, for the specified image.
    * @param imageName the image name to test

operator/src/main/java/oracle/kubernetes/operator/helpers/PodStepContext.java

@@ -90,6 +90,7 @@
 import static oracle.kubernetes.common.helpers.AuxiliaryImageEnvVars.AUXILIARY_IMAGE_MOUNT_PATH;
 import static oracle.kubernetes.common.logging.MessageKeys.CYCLING_POD_EVICTED;
 import static oracle.kubernetes.common.logging.MessageKeys.CYCLING_POD_SPEC_CHANGED;
+import static oracle.kubernetes.common.utils.CommonUtils.stream;
 import static oracle.kubernetes.operator.DomainStatusUpdater.createKubernetesFailureSteps;
 import static oracle.kubernetes.operator.IntrospectorConfigMapConstants.NUM_CONFIG_MAPS;
 import static oracle.kubernetes.operator.KubernetesConstants.DEFAULT_EXPORTER_SIDECAR_PORT;
@@ -1253,8 +1254,8 @@ private void convertAuxImagesInitContainerVolumeAndMounts(V1Pod recipe, V1Pod cu
 
     private void restoreMetricsExporterSidecarPortTcpMetrics(V1Pod recipe, V1Pod currentPod) {
       V1PodSpec podSpec = recipe.getSpec();
-      podSpec.getContainers().stream().filter(c -> "monitoring-exporter".equals(c.getName()))
-          .findFirst().flatMap(c -> c.getPorts().stream().filter(p -> "metrics".equals(p.getName()))
+      stream(podSpec.getContainers()).filter(c -> "monitoring-exporter".equals(c.getName()))
+          .findFirst().flatMap(c -> stream(c.getPorts()).filter(p -> "metrics".equals(p.getName()))
               .findFirst()).ifPresent(p -> p.setName("tcp-metrics"));
     }