Enable kubectl-get to strip managed fields

staging/src/k8s.io/cli-runtime/pkg/genericclioptions/json_yaml_flags.go

@@ -36,6 +36,7 @@ func (f *JSONYamlPrintFlags) AllowedFormats() []string {
 // Given the following flag values, a printer can be requested that knows
 // how to handle printing based on these values.
 type JSONYamlPrintFlags struct {
+	showManagedFields bool
 }
 
 // ToPrinter receives an outputFormat and returns a printer capable of
@@ -55,12 +56,17 @@ func (f *JSONYamlPrintFlags) ToPrinter(outputFormat string) (printers.ResourcePr
 		return nil, NoCompatiblePrinterError{OutputFormat: &outputFormat, AllowedFormats: f.AllowedFormats()}
 	}
 
+	if !f.showManagedFields {
+		printer = &printers.OmitManagedFieldsPrinter{Delegate: printer}
+	}
 	return printer, nil
 }
 
 // AddFlags receives a *cobra.Command reference and binds
 // flags related to JSON or Yaml printing to it
-func (f *JSONYamlPrintFlags) AddFlags(c *cobra.Command) {}
+func (f *JSONYamlPrintFlags) AddFlags(c *cobra.Command) {
+	c.Flags().BoolVar(&f.showManagedFields, "show-managed-fields", f.showManagedFields, "If true, keep the managedFields when printing objects in JSON or YAML format.")
+}
 
 // NewJSONYamlPrintFlags returns flags associated with
 // yaml or json printing, with default values set.

staging/src/k8s.io/cli-runtime/pkg/printers/BUILD

@@ -8,6 +8,7 @@ go_library(
         "interface.go",
         "json.go",
         "jsonpath.go",
+        "managedfields.go",
         "name.go",
         "sourcechecker.go",
         "tableprinter.go",
@@ -39,6 +40,7 @@ go_test(
     srcs = [
         "json_test.go",
         "jsonpath_test.go",
+        "managedfields_test.go",
         "sourcechecker_test.go",
         "tableprinter_test.go",
         "template_test.go",
@@ -54,6 +56,7 @@ go_test(
         "//staging/src/k8s.io/apimachinery/pkg/util/json:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes/scheme:go_default_library",
+        "//vendor/github.com/stretchr/testify/require:go_default_library",
         "//vendor/sigs.k8s.io/yaml:go_default_library",
     ],
 )

staging/src/k8s.io/cli-runtime/pkg/printers/managedfields.go

@@ -0,0 +1,59 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package printers
+
+import (
+	"io"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+// OmitManagedFieldsPrinter wraps an existing printer and omits the managed fields from the object
+// before printing it.
+type OmitManagedFieldsPrinter struct {
+	Delegate ResourcePrinter
+}
+
+var _ ResourcePrinter = (*OmitManagedFieldsPrinter)(nil)
+
+func omitManagedFields(o runtime.Object) runtime.Object {
+	a, err := meta.Accessor(o)
+	if err != nil {
+		// The object is not a `metav1.Object`, ignore it.
+		return o
+	}
+	a.SetManagedFields(nil)
+	return o
+}
+
+// PrintObj copies the object and omits the managed fields from the copied object before printing it.
+func (p *OmitManagedFieldsPrinter) PrintObj(obj runtime.Object, w io.Writer) error {
+	if obj == nil {
+		return p.Delegate.PrintObj(obj, w)
+	}
+	if meta.IsListType(obj) {
+		obj = obj.DeepCopyObject()
+		_ = meta.EachListItem(obj, func(item runtime.Object) error {
+			omitManagedFields(item)
+			return nil
+		})
+	} else if _, err := meta.Accessor(obj); err == nil {
+		obj = omitManagedFields(obj.DeepCopyObject())
+	}
+	return p.Delegate.PrintObj(obj, w)
+}

staging/src/k8s.io/cli-runtime/pkg/printers/managedfields_test.go

@@ -0,0 +1,106 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package printers
+
+import (
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+type testResourcePrinter func(object runtime.Object, writer io.Writer) error
+
+func (p testResourcePrinter) PrintObj(o runtime.Object, w io.Writer) error {
+	return p(o, w)
+}
+
+func TestOmitManagedFieldsPrinter(t *testing.T) {
+	testCases := []struct {
+		name     string
+		object   runtime.Object
+		expected runtime.Object
+	}{
+		{
+			name: "pod without managedFields",
+			object: &v1.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "pod1"},
+			},
+			expected: &v1.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "pod1"},
+			},
+		},
+		{
+			name: "pod with managedFields",
+			object: &v1.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: "pod1",
+					ManagedFields: []metav1.ManagedFieldsEntry{
+						{Manager: "kubectl", Operation: metav1.ManagedFieldsOperationApply},
+					},
+				},
+			},
+			expected: &v1.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "pod1"},
+			},
+		},
+		{
+			name: "pod list",
+			object: &v1.PodList{
+				Items: []v1.Pod{
+					{
+						ObjectMeta: metav1.ObjectMeta{
+							Name:          "pod1",
+							ManagedFields: []metav1.ManagedFieldsEntry{},
+						},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{
+							Name: "pod2",
+							ManagedFields: []metav1.ManagedFieldsEntry{
+								{Manager: "kubectl", Operation: metav1.ManagedFieldsOperationApply},
+							},
+						},
+					},
+					{ObjectMeta: metav1.ObjectMeta{Name: "pod3"}},
+				},
+			},
+			expected: &v1.PodList{
+				Items: []v1.Pod{
+					{ObjectMeta: metav1.ObjectMeta{Name: "pod1"}},
+					{ObjectMeta: metav1.ObjectMeta{Name: "pod2"}},
+					{ObjectMeta: metav1.ObjectMeta{Name: "pod3"}},
+				},
+			},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			r := require.New(t)
+			delegate := func(o runtime.Object, w io.Writer) error {
+				r.Equal(tc.expected, o)
+				return nil
+			}
+			p := OmitManagedFieldsPrinter{Delegate: testResourcePrinter(delegate)}
+			r.NoError(p.PrintObj(tc.object, nil))
+		})
+	}
+}

test/cmd/apply.sh

@@ -35,7 +35,7 @@ run_kubectl_apply_tests() {
   # Post-Condition: pod "test-pod" has configuration annotation
   grep -q kubectl.kubernetes.io/last-applied-configuration <<< "$(kubectl get pods test-pod -o yaml "${kube_flags[@]:?}")"
   # pod has field manager for kubectl client-side apply
-  output_message=$(kubectl get -f hack/testdata/pod.yaml -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
+  output_message=$(kubectl get --show-managed-fields -f hack/testdata/pod.yaml -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
   kube::test::if_has_string "${output_message}" 'kubectl-client-side-apply'
   # Clean up
   kubectl delete pods test-pod "${kube_flags[@]:?}"
@@ -367,7 +367,7 @@ run_kubectl_server_side_apply_tests() {
   # Post-Condition: pod "test-pod" is created
   kube::test::get_object_assert 'pods test-pod' "{{${labels_field:?}.name}}" 'test-pod-label'
   # pod has field manager for kubectl server-side apply
-  output_message=$(kubectl get -f hack/testdata/pod.yaml -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
+  output_message=$(kubectl get --show-managed-fields -f hack/testdata/pod.yaml -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
   kube::test::if_has_string "${output_message}" 'kubectl'
   # pod has custom field manager
   kubectl apply --server-side --field-manager=my-field-manager --force-conflicts -f hack/testdata/pod.yaml "${kube_flags[@]:?}"

test/cmd/apps.sh

@@ -43,7 +43,7 @@ run_daemonset_tests() {
   kubectl set resources daemonsets/bind "${kube_flags[@]:?}" --limits=cpu=200m,memory=512Mi
   kube::test::get_object_assert 'daemonsets bind' "{{${generation_field:?}}}" '4'
   # pod has field for kubectl set field manager
-  output_message=$(kubectl get daemonsets bind -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
+  output_message=$(kubectl get daemonsets bind --show-managed-fields -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
   kube::test::if_has_string "${output_message}" 'kubectl-set'
 
   # Rollout restart should change generation
@@ -340,7 +340,7 @@ run_deployment_tests() {
   rs="$(kubectl get rs "${newrs}" -o yaml)"
   kube::test::if_has_string "${rs}" "deployment.kubernetes.io/revision: \"6\""
   # Deployment has field for kubectl rollout field manager
-  output_message=$(kubectl get deployment nginx -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
+  output_message=$(kubectl get deployment nginx --show-managed-fields -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
   kube::test::if_has_string "${output_message}" 'kubectl-rollout'
   # Create second deployment
   ${SED} "s/name: nginx$/name: nginx2/" hack/testdata/deployment-revision1.yaml | kubectl create -f - "${kube_flags[@]:?}"
@@ -662,7 +662,7 @@ run_rs_tests() {
   kube::test::get_object_assert 'rs frontend' "{{${generation_field:?}}}" '5'
 
   # RS has field for kubectl set field manager
-  output_message=$(kubectl get rs frontend -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
+  output_message=$(kubectl get rs frontend --show-managed-fields -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
   kube::test::if_has_string "${output_message}" 'kubectl-set'
 
   ### Delete replica set with id

test/cmd/core.sh

@@ -81,7 +81,7 @@ run_pod_tests() {
   kube::test::get_object_assert 'pod/valid-pod' "{{$id_field}}" 'valid-pod'
   kube::test::get_object_assert 'pods/valid-pod' "{{$id_field}}" 'valid-pod'
   # pod has field manager for kubectl create
-  output_message=$(kubectl get -f test/fixtures/doc-yaml/admin/limitrange/valid-pod.yaml -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
+  output_message=$(kubectl get --show-managed-fields -f test/fixtures/doc-yaml/admin/limitrange/valid-pod.yaml -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
   kube::test::if_has_string "${output_message}" 'kubectl-create'
   # Repeat above test using jsonpath template
   kube::test::get_object_jsonpath_assert pods "{.items[*]$id_field}" 'valid-pod'
@@ -1014,7 +1014,7 @@ run_service_tests() {
   # Show dry-run works on running selector
   kubectl set selector services redis-master role=padawan --dry-run=client -o yaml "${kube_flags[@]}"
   kubectl set selector services redis-master role=padawan --dry-run=server -o yaml "${kube_flags[@]}"
-  output_message=$(kubectl get services redis-master -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
+  output_message=$(kubectl get services redis-master --show-managed-fields -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
   kube::test::if_has_string "${output_message}" 'kubectl-set'
   ! kubectl set selector services redis-master role=padawan --local -o yaml "${kube_flags[@]}" || exit 1
   kube::test::get_object_assert 'services redis-master' "{{range$service_selector_field}}{{.}}:{{end}}" "redis:master:backend:"

test/cmd/node-management.sh

@@ -88,7 +88,7 @@ __EOF__
   kubectl taint node 127.0.0.1 dedicated:PreferNoSchedule
   kube::test::get_object_assert "nodes 127.0.0.1" '{{range .spec.taints}}{{if eq .key \"dedicated\"}}{{.key}}={{.value}}:{{.effect}}{{end}}{{end}}' "dedicated=<no value>:PreferNoSchedule"
   # Node has field manager for kubectl taint
-  output_message=$(kubectl get node 127.0.0.1 -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
+  output_message=$(kubectl get node 127.0.0.1 --show-managed-fields -o=jsonpath='{.metadata.managedFields[*].manager}' "${kube_flags[@]:?}" 2>&1)
   kube::test::if_has_string "${output_message}" 'kubectl-taint'
   # Dry-run remove a taint
   kubectl taint node 127.0.0.1 --dry-run=client dedicated-