kubectl-hns: Add "delete" command

docs/user-guide/how-to.md

@@ -236,6 +236,12 @@ Instead, you must delete its anchor (note that `subns` is a short form of
 $ kubectl delete subns child -n parent
 ```
 
+You can also use the `kubectl-hns` plugin to delete subnamespaces.
+
+```
+$ kubectl hns delete child -n parent
+```
+
 This _seems_ to imply that if you delete a _parent_ namespace, all its
 subnamespace children (and their descendants) will be deleted as well, since all
 objects in a namespace (such as anchors) are deleted along with the namespace.

docs/user-guide/quickstart.md

@@ -615,6 +615,11 @@ kubectl delete subns service-3 -n team-a
 Note that `subns` is a short form for `subnamespaceanchor` or
 `subnamespaceanchor.hnc.x-k8s.io`.
 
+You can also use the `kubectl-hns` plugin to delete subnamespaces.
+
+```bash
+kubectl hns delete service-3 -n team-a
+```
 
 Now try to delete `service-1` in the same way, but you'll see it doesn't work:
 
@@ -675,6 +680,12 @@ team-a
 [s] indicates subnamespaces
 ```
 
+You can also do the above steps in one command run with the `kubectl-hns` plugin:
+
+```bash
+kubectl hns delete service-1 -n team-a --allowCascadingDeletion
+```
+
 There's an important difference between subnamespaces and regular child
 namespace, also known as a full namespace. A subnamespace is created by HNC due
 to an anchor being created in the parent; when that anchor is deleted, the

internal/kubectl/delete.go

@@ -0,0 +1,63 @@
+/*
+
+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 kubectl
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var deleteCmd = &cobra.Command{
+	Use:   "delete -n PARENT CHILD",
+	Short: "Deletes a subnamespace under the given parent.",
+	Example: `# Delete the 'foo' anchor in the parent 'bar' namespace
+	kubectl hns delete foo -n bar
+
+	# Allow 'foo' to be cascading deleted and delete it
+	kubectl hns delete foo -n bar --allowCascadingDeletion`,
+	Args: cobra.ExactArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		nnm := args[0]
+
+		parent, _ := cmd.Flags().GetString("namespace")
+		if parent == "" {
+			fmt.Println("Error: parent must be set via --namespace or -n")
+			os.Exit(1)
+		}
+
+		allowCD, _ := cmd.Flags().GetBool("allowCascadingDeletion")
+		if allowCD {
+			hc := client.getHierarchy(nnm)
+			if hc.Spec.AllowCascadingDeletion {
+				fmt.Printf("Cascading deletion for '%s' is already set to 'true'; unchanged\n", nnm)
+			} else {
+				fmt.Printf("Allowing cascading deletion on '%s'\n", nnm)
+				hc.Spec.AllowCascadingDeletion = true
+				client.updateHierarchy(hc, fmt.Sprintf("update the hierarchical configuration of %s", nnm))
+			}
+		}
+
+		client.deleteAnchor(parent, nnm)
+	},
+}
+
+func newDeleteCmd() *cobra.Command {
+	deleteCmd.Flags().StringP("namespace", "n", "", "The parent namespace for the new subnamespace")
+	deleteCmd.Flags().BoolP("allowCascadingDeletion", "a", false, "Allows cascading deletion of its subnamespaces.")
+	return deleteCmd
+}

internal/kubectl/root.go

@@ -49,6 +49,7 @@ type Client interface {
 	getHierarchy(nnm string) *api.HierarchyConfiguration
 	updateHierarchy(hier *api.HierarchyConfiguration, reason string)
 	createAnchor(nnm string, hnnm string)
+	deleteAnchor(nnm string, hnnm string)
 	getAnchorStatus(nnm string) anchorStatus
 	getHNCConfig() *api.HNCConfiguration
 	updateHNCConfig(*api.HNCConfiguration)
@@ -102,6 +103,7 @@ func init() {
 	rootCmd.AddCommand(newDescribeCmd())
 	rootCmd.AddCommand(newTreeCmd())
 	rootCmd.AddCommand(newCreateCmd())
+	rootCmd.AddCommand(newDeleteCmd())
 	rootCmd.AddCommand(newConfigCmd())
 	rootCmd.AddCommand(newVersionCmd())
 	rootCmd.AddCommand(newHrqCmd())
@@ -186,6 +188,18 @@ func (cl *realClient) createAnchor(nnm string, hnnm string) {
 	fmt.Printf("Successfully created %q subnamespace anchor in %q namespace\n", hnnm, nnm)
 }
 
+func (cl *realClient) deleteAnchor(nnm string, hnnm string) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	err := hncClient.Delete().Resource(api.Anchors).Namespace(nnm).Name(hnnm).Do(ctx).Error()
+	if err != nil {
+		fmt.Printf("\nCould not delete subnamespace anchor.\nReason: %s\n", err)
+		os.Exit(1)
+	}
+	fmt.Printf("Successfully deleted %q subnamespace anchor in %q namespace\n", hnnm, nnm)
+}
+
 func (cl *realClient) getHNCConfig() *api.HNCConfiguration {
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()

test/e2e/quickstart_test.go

@@ -253,6 +253,12 @@ spec:
 		// show how to delete a subns correctly
 		MustNotRun("kubectl delete ns", nsService3)
 		MustRun("kubectl delete subns", nsService3, "-n", nsTeamA)
+
+		// show how to delete a subns correctly with the kubectl-hns plugin
+		CreateSubnamespace(nsService4, nsTeamA)
+		MustNotRun("kubectl hns delete", nsService4)
+		MustRun("kubectl hns delete", nsService4, "-n", nsTeamA)
+
 		// This should not run because service-1 contains its own subnamespace that would be deleted with it,
 		MustNotRun("kubectl delete subns", nsService1, "-n", nsTeamA)
 
@@ -263,6 +269,21 @@ spec:
 			"└── [s] " + nsService2
 		RunShouldContain(expected, defTimeout, "kubectl hns tree", nsTeamA)
 
+		// cascading deletion with the kubectl-hns plugin
+		CreateSubnamespace(nsService1, nsTeamA)
+		CreateSubnamespace(nsService4, nsService1)
+		expected = "" +
+			nsService1 + "\n" +
+			"└── [s] " + nsService4
+		RunShouldContain(expected, defTimeout, "kubectl hns tree", nsService1, "-n", nsTeamA)
+		MustNotRun("kubectl hns delete", nsService1, "-n", nsTeamA)
+		MustRun("kubectl hns delete", nsService1, "-n", nsTeamA, "--allowCascadingDeletion")
+		expected = "" +
+			nsTeamA + "\n" +
+			"└── [s] " + nsService2
+		// cascading deletion of its subnamespaces takes time
+		RunShouldContain(expected, cleanupTimeout, "kubectl hns tree", nsTeamA)
+
 		// Show the difference of a subns and regular child ns
 		CreateSubnamespace(nsService4, nsTeamA)
 		expected = "" +