[Don't Review] Add a utility to get container name from podoptions

pkg/kube/pod.go

@@ -199,6 +199,17 @@ func GetPodObjectFromPodOptions(cli kubernetes.Interface, opts *PodOptions) (*v1
 	return pod, nil
 }
 
+// ContainerNameFromPodOptsOrDefault returns the container name if it's set in
+// the passed `podOptions` value. If not, it's returns the default container
+// name. This should be used whenever we create pods for Kanister functions.
+func ContainerNameFromPodOptsOrDefault(po *PodOptions) string {
+	if po.ContainerName != "" {
+		return po.ContainerName
+	}
+
+	return defaultContainerName
+}
+
 // CreatePod creates a pod with a single container based on the specified image
 func CreatePod(ctx context.Context, cli kubernetes.Interface, opts *PodOptions) (*v1.Pod, error) {
 	pod, err := GetPodObjectFromPodOptions(cli, opts)

pkg/kube/pod_test.go

@@ -881,3 +881,27 @@ func (s *PodSuite) TestSetLifecycleHook(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(pod.Spec.Containers[0].Lifecycle, DeepEquals, lch)
 }
+
+func (s *PodControllerTestSuite) TestContainerNameFromPodOptsOrDefault(c *C) {
+	for _, tc := range []struct {
+		podOptsContainerName  string
+		expectedContainerName string
+	}{
+		{
+			podOptsContainerName:  "conone",
+			expectedContainerName: "conone",
+		},
+		{
+			podOptsContainerName:  "",
+			expectedContainerName: defaultContainerName,
+		},
+	} {
+		name := ContainerNameFromPodOptsOrDefault(&PodOptions{
+			ContainerName: tc.podOptsContainerName,
+		})
+		c.Assert(name, Equals, tc.expectedContainerName)
+	}
+
+	name := ContainerNameFromPodOptsOrDefault(&PodOptions{})
+	c.Assert(name, Equals, defaultContainerName)
+}