From 71c9d3e708d6a035b2e047ec3fc6bc513013a4ef Mon Sep 17 00:00:00 2001
From: astraw99 <wangchengiscool@gmail.com>
Date: Fri, 8 Aug 2025 18:33:35 +0800
Subject: [PATCH] Add valid container name info in the kubectl logs/exec output

---
 pkg/registry/core/pod/strategy.go                     | 11 ++++++++++-
 pkg/registry/core/pod/strategy_test.go                |  2 +-
 .../src/k8s.io/kubectl/pkg/cmd/attach/attach_test.go  |  2 +-
 .../src/k8s.io/kubectl/pkg/cmd/util/podcmd/podcmd.go  |  2 +-
 .../kubectl/pkg/polymorphichelpers/logsforobject.go   |  2 +-
 5 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/pkg/registry/core/pod/strategy.go b/pkg/registry/core/pod/strategy.go
index ccdf35e76f4..06e6efa08e4 100644
--- a/pkg/registry/core/pod/strategy.go
+++ b/pkg/registry/core/pod/strategy.go
@@ -47,10 +47,13 @@ import (
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/apiserver/pkg/warning"
 	"k8s.io/client-go/tools/cache"
+	"k8s.io/klog/v2"
+	"k8s.io/kubectl/pkg/cmd/util/podcmd"
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
 	podutil "k8s.io/kubernetes/pkg/api/pod"
 	api "k8s.io/kubernetes/pkg/apis/core"
 	"k8s.io/kubernetes/pkg/apis/core/helper/qos"
+	apiscorev1 "k8s.io/kubernetes/pkg/apis/core/v1"
 	corevalidation "k8s.io/kubernetes/pkg/apis/core/validation"
 	"k8s.io/kubernetes/pkg/features"
 	"k8s.io/kubernetes/pkg/kubelet/client"
@@ -836,7 +839,13 @@ func validateContainer(container string, pod *api.Pod) (string, error) {
 		}
 	} else {
 		if !podHasContainerWithName(pod, container) {
-			return "", errors.NewBadRequest(fmt.Sprintf("container %s is not valid for pod %s", container, pod.Name))
+			coreV1Pod := &apiv1.Pod{}
+			if err := apiscorev1.Convert_core_Pod_To_v1_Pod(pod, coreV1Pod, nil); err != nil {
+				// This should never happen, but if it does, we want to log an error.
+				klog.ErrorS(err, "Pod failed to convert to v1", "pod", klog.KObj(pod))
+				return "", errors.NewBadRequest(fmt.Sprintf("container %s is not valid for pod %s", container, pod.Name))
+			}
+			return "", errors.NewBadRequest(fmt.Sprintf("container %s is not valid for pod %s out of: %s", container, pod.Name, podcmd.AllContainerNames(coreV1Pod)))
 		}
 	}
 
diff --git a/pkg/registry/core/pod/strategy_test.go b/pkg/registry/core/pod/strategy_test.go
index 65fe5dbbf11..6c850d9081d 100644
--- a/pkg/registry/core/pod/strategy_test.go
+++ b/pkg/registry/core/pod/strategy_test.go
@@ -582,7 +582,7 @@ func TestCheckLogLocation(t *testing.T) {
 			opts: &api.PodLogOptions{
 				Container: "unknown",
 			},
-			expectedErr:       errors.NewBadRequest("container unknown is not valid for pod test"),
+			expectedErr:       errors.NewBadRequest("container unknown is not valid for pod test out of: container1, container2"),
 			expectedTransport: nil,
 		},
 		{
diff --git a/staging/src/k8s.io/kubectl/pkg/cmd/attach/attach_test.go b/staging/src/k8s.io/kubectl/pkg/cmd/attach/attach_test.go
index 6a599656e45..7796c7acb93 100644
--- a/staging/src/k8s.io/kubectl/pkg/cmd/attach/attach_test.go
+++ b/staging/src/k8s.io/kubectl/pkg/cmd/attach/attach_test.go
@@ -276,7 +276,7 @@ func TestAttach(t *testing.T) {
 			attachPath:   "/api/" + version + "/namespaces/test/pods/foo/attach",
 			pod:          attachPod(),
 			container:    "foo",
-			expectedErr:  "cannot attach to the container: container foo not found in pod foo",
+			expectedErr:  "cannot attach to the container: container foo not found in pod foo out of: bar, debugger (ephem), initfoo (init)",
 		},
 	}
 	for _, test := range tests {
diff --git a/staging/src/k8s.io/kubectl/pkg/cmd/util/podcmd/podcmd.go b/staging/src/k8s.io/kubectl/pkg/cmd/util/podcmd/podcmd.go
index bf760645d4a..d36c5481fd4 100644
--- a/staging/src/k8s.io/kubectl/pkg/cmd/util/podcmd/podcmd.go
+++ b/staging/src/k8s.io/kubectl/pkg/cmd/util/podcmd/podcmd.go
@@ -59,7 +59,7 @@ func FindOrDefaultContainerByName(pod *v1.Pod, name string, quiet bool, warn io.
 	if len(name) > 0 {
 		container, _ = FindContainerByName(pod, name)
 		if container == nil {
-			return nil, fmt.Errorf("container %s not found in pod %s", name, pod.Name)
+			return nil, fmt.Errorf("container %s not found in pod %s out of: %s", name, pod.Name, AllContainerNames(pod))
 		}
 		return container, nil
 	}
diff --git a/staging/src/k8s.io/kubectl/pkg/polymorphichelpers/logsforobject.go b/staging/src/k8s.io/kubectl/pkg/polymorphichelpers/logsforobject.go
index 87968b789d0..064ea910f99 100644
--- a/staging/src/k8s.io/kubectl/pkg/polymorphichelpers/logsforobject.go
+++ b/staging/src/k8s.io/kubectl/pkg/polymorphichelpers/logsforobject.go
@@ -116,7 +116,7 @@ func logsForObjectWithClient(clientset corev1client.CoreV1Interface, object, opt
 
 			container, fieldPath := podcmd.FindContainerByName(t, currOpts.Container)
 			if container == nil {
-				return nil, fmt.Errorf("container %s is not valid for pod %s", currOpts.Container, t.Name)
+				return nil, fmt.Errorf("container %s is not valid for pod %s out of: %s", currOpts.Container, t.Name, podcmd.AllContainerNames(t))
 			}
 			ref, err := reference.GetPartialReference(scheme.Scheme, t, fieldPath)
 			if err != nil {