Adding support for pod level resources in kubectl

1. Add support for pod level resources in kubectl
2. Reuse the existing method to describe container resources and generalize it to describe both pod and container level resources

Author: ndixita

staging/src/k8s.io/kubectl/pkg/describe/describe.go

@@ -838,6 +838,11 @@ func describePod(pod *corev1.Pod, events *corev1.EventList) (string, error) {
 			w.Write(LEVEL_0, "NominatedNodeName:\t%s\n", pod.Status.NominatedNodeName)
 		}
 
+		if pod.Spec.Resources != nil {
+			w.Write(LEVEL_0, "Resources:\n")
+			describeResources(pod.Spec.Resources, w, LEVEL_1)
+		}
+
 		if len(pod.Spec.InitContainers) > 0 {
 			describeContainers("Init Containers", pod.Spec.InitContainers, pod.Status.InitContainerStatuses, EnvValueRetriever(pod), w, "")
 		}
@@ -1800,7 +1805,7 @@ func describeContainers(label string, containers []corev1.Container, containerSt
 		if ok {
 			describeContainerState(status, w)
 		}
-		describeContainerResource(container, w)
+		describeResources(&container.Resources, w, LEVEL_2)
 		describeContainerProbe(container, w)
 		if len(container.EnvFrom) > 0 {
 			describeContainerEnvFrom(container, resolverFn, w)
@@ -1886,22 +1891,25 @@ func describeContainerCommand(container corev1.Container, w PrefixWriter) {
 	}
 }
 
-func describeContainerResource(container corev1.Container, w PrefixWriter) {
-	resources := container.Resources
+func describeResources(resources *corev1.ResourceRequirements, w PrefixWriter, level int) {
+	if resources == nil {
+		return
+	}
+
 	if len(resources.Limits) > 0 {
-		w.Write(LEVEL_2, "Limits:\n")
+		w.Write(level, "Limits:\n")
 	}
 	for _, name := range SortedResourceNames(resources.Limits) {
 		quantity := resources.Limits[name]
-		w.Write(LEVEL_3, "%s:\t%s\n", name, quantity.String())
+		w.Write(level+1, "%s:\t%s\n", name, quantity.String())
 	}
 
 	if len(resources.Requests) > 0 {
-		w.Write(LEVEL_2, "Requests:\n")
+		w.Write(level, "Requests:\n")
 	}
 	for _, name := range SortedResourceNames(resources.Requests) {
 		quantity := resources.Requests[name]
-		w.Write(LEVEL_3, "%s:\t%s\n", name, quantity.String())
+		w.Write(level+1, "%s:\t%s\n", name, quantity.String())
 	}
 }
 

staging/src/k8s.io/kubectl/pkg/describe/describe_test.go

@@ -1179,6 +1179,71 @@ func VerifyDatesInOrder(
 	}
 }
 
+func TestDescribeResources(t *testing.T) {
+	testCases := []struct {
+		resources        *corev1.ResourceRequirements
+		expectedElements map[string]int
+	}{
+		{
+			resources:        &corev1.ResourceRequirements{},
+			expectedElements: map[string]int{},
+		},
+		{
+			resources: &corev1.ResourceRequirements{
+				Requests: corev1.ResourceList{
+					corev1.ResourceCPU:    resource.MustParse("1000"),
+					corev1.ResourceMemory: resource.MustParse("100Mi"),
+				},
+				Limits: corev1.ResourceList{
+					corev1.ResourceCPU:    resource.MustParse("1000"),
+					corev1.ResourceMemory: resource.MustParse("100Mi"),
+				},
+			},
+			expectedElements: map[string]int{"cpu": 2, "memory": 2, "Requests": 1, "Limits": 1, "1k": 2, "100Mi": 2},
+		},
+		{
+			resources: &corev1.ResourceRequirements{
+				Limits: corev1.ResourceList{
+					corev1.ResourceCPU:    resource.MustParse("1000"),
+					corev1.ResourceMemory: resource.MustParse("100Mi"),
+				},
+			},
+			expectedElements: map[string]int{"cpu": 1, "memory": 1, "Limits": 1, "1k": 1, "100Mi": 1},
+		},
+		{
+			resources: &corev1.ResourceRequirements{
+				Requests: corev1.ResourceList{
+					corev1.ResourceCPU:    resource.MustParse("1000"),
+					corev1.ResourceMemory: resource.MustParse("100Mi"),
+				},
+			},
+			expectedElements: map[string]int{"cpu": 1, "memory": 1, "Requests": 1, "1k": 1, "100Mi": 1},
+		},
+	}
+
+	for i, testCase := range testCases {
+		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
+			out := new(bytes.Buffer)
+			writer := NewPrefixWriter(out)
+			describeResources(testCase.resources, writer, LEVEL_1)
+			output := out.String()
+			gotElements := make(map[string]int)
+			for key, val := range testCase.expectedElements {
+				count := strings.Count(output, key)
+				if count == 0 {
+					t.Errorf("expected to find %q in output: %q", val, output)
+					continue
+				}
+				gotElements[key] = count
+			}
+
+			if !reflect.DeepEqual(gotElements, testCase.expectedElements) {
+				t.Errorf("Expected %v, got %v in output string: %q", testCase.expectedElements, gotElements, output)
+			}
+		})
+	}
+}
+
 func TestDescribeContainers(t *testing.T) {
 	trueVal := true
 	testCases := []struct {