Fix incorrect message when attaching to ephemeral containers

staging/src/k8s.io/kubectl/pkg/cmd/attach/attach.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"io"
 	"net/url"
+	"strings"
 	"time"
 
 	"github.com/spf13/cobra"
@@ -286,8 +287,8 @@ func (o *AttachOptions) Run() error {
 		return err
 	}
 
-	if !o.Quiet && o.Stdin && t.Raw && o.Pod.Spec.RestartPolicy == corev1.RestartPolicyAlways {
+	if msg := o.reattachMessage(containerToAttach.Name, t.Raw); msg != "" {
-		fmt.Fprintf(o.Out, "Session ended, resume using '%s %s -c %s -i -t' command when the pod is running\n", o.CommandName, o.Pod.Name, containerToAttach.Name)
+		fmt.Fprintln(o.Out, msg)
 	}
 	return nil
 }
@@ -317,3 +318,15 @@ func (o *AttachOptions) GetContainerName(pod *corev1.Pod) (string, error) {
 	}
 	return c.Name, nil
 }
+
+// reattachMessage returns a message to print after attach has completed, or
+// the empty string if no message should be printed.
+func (o *AttachOptions) reattachMessage(containerName string, rawTTY bool) string {
+	if o.Quiet || !o.Stdin || !rawTTY || o.Pod.Spec.RestartPolicy != corev1.RestartPolicyAlways {
+		return ""
+	}
+	if _, path := podcmd.FindContainerByName(o.Pod, containerName); strings.HasPrefix(path, "spec.ephemeralContainers") {
+		return fmt.Sprintf("Session ended, the ephemeral container will not be restarted but may be reattached using '%s %s -c %s -i -t' if it is still running", o.CommandName, o.Pod.Name, containerName)
+	}
+	return fmt.Sprintf("Session ended, resume using '%s %s -c %s -i -t' command when the pod is running", o.CommandName, o.Pod.Name, containerName)
+}

staging/src/k8s.io/kubectl/pkg/cmd/attach/attach_test.go

@@ -484,3 +484,76 @@ func setDefaultContainer(pod *corev1.Pod, name string) *corev1.Pod {
 	pod.Annotations[podcmd.DefaultContainerAnnotationName] = name
 	return pod
 }
+
+func TestReattachMessage(t *testing.T) {
+	tests := []struct {
+		name          string
+		pod           *corev1.Pod
+		rawTTY, stdin bool
+		container     string
+		expected      string
+	}{
+		{
+			name:      "normal interactive session",
+			pod:       attachPod(),
+			container: "bar",
+			rawTTY:    true,
+			stdin:     true,
+			expected:  "Session ended, resume using",
+		},
+		{
+			name:      "no stdin",
+			pod:       attachPod(),
+			container: "bar",
+			rawTTY:    true,
+			stdin:     false,
+			expected:  "",
+		},
+		{
+			name:      "not connected to a real TTY",
+			pod:       attachPod(),
+			container: "bar",
+			rawTTY:    false,
+			stdin:     true,
+			expected:  "",
+		},
+		{
+			name: "no restarts",
+			pod: &corev1.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo", Namespace: "test"},
+				Spec: corev1.PodSpec{
+					RestartPolicy: corev1.RestartPolicyNever,
+					Containers:    []corev1.Container{{Name: "bar"}},
+				},
+				Status: corev1.PodStatus{Phase: corev1.PodRunning},
+			},
+			container: "bar",
+			rawTTY:    true,
+			stdin:     true,
+			expected:  "",
+		},
+		{
+			name:      "ephemeral container",
+			pod:       attachPod(),
+			container: "debugger",
+			rawTTY:    true,
+			stdin:     true,
+			expected:  "Session ended, the ephemeral container will not be restarted",
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			options := &AttachOptions{
+				StreamOptions: exec.StreamOptions{
+					Stdin: test.stdin,
+				},
+				Pod: test.pod,
+			}
+			if msg := options.reattachMessage(test.container, test.rawTTY); test.expected == "" && msg != "" {
+				t.Errorf("reattachMessage(%v, %v) = %q, wanted empty string", test.container, test.rawTTY, msg)
+			} else if !strings.Contains(msg, test.expected) {
+				t.Errorf("reattachMessage(%v, %v) = %q, want string containing %q", test.container, test.rawTTY, msg, test.expected)
+			}
+		})
+	}
+}

staging/src/k8s.io/kubectl/pkg/cmd/debug/debug.go

@@ -364,7 +364,6 @@ func (o *DebugOptions) Run(f cmdutil.Factory, cmd *cobra.Command) error {
 					TTY:       o.TTY,
 					Quiet:     o.Quiet,
 				},
-				// TODO(verb): kubectl prints an incorrect "Session ended" message for debug containers.
 				CommandName: cmd.Parent().CommandPath() + " attach",
 
 				Attach: &attach.DefaultRemoteAttach{},