fix(action): Protects against current resource conflicts

Currently, if using the --atomic flag or deleting a release that failed due to an already existing
resource, Helm will deleting those resources that aren't managed by it. This PR fixes the issue
by checking for pre-existing resources during install and upgrade. This is done as a validation
step so the release will not even be started if resources currently exist. This PR is inspired by
@xchapter7x's work in #3477.

This also fixes a small bug in upgrade where deletes fail if the resource was already deletes

Fixes #6407

Signed-off-by: Taylor Thomas <taylor.thomas@microsoft.com>

pkg/action/install.go

@@ -231,6 +231,16 @@ func (i *Install) Run(chrt *chart.Chart, vals map[string]interface{}) (*release.
 		return rel, nil
 	}
 
+	// Install requires an extra validation step of checking that resources
+	// don't already exist before we actually create resources. If we continue
+	// forward and create the release object with resources that already exist,
+	// we'll end up in a state where we will delete those resources upon
+	// deleting the release because the manifest will be pointing at that
+	// resource
+	if err := existingResourceConflict(resources); err != nil {
+		return nil, errors.Wrap(err, "rendered manifests contain a resource that already exists. Unable to continue with install")
+	}
+
 	// If Replace is true, we need to supercede the last release.
 	if i.Replace {
 		if err := i.replaceRelease(rel); err != nil {

pkg/action/upgrade.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/pkg/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/cli-runtime/pkg/resource"
 
 	"helm.sh/helm/pkg/chart"
 	"helm.sh/helm/pkg/chartutil"
@@ -88,13 +89,6 @@ func (u *Upgrade) Run(name string, chart *chart.Chart, vals map[string]interface
 
 	u.cfg.Releases.MaxHistory = u.MaxHistory
 
-	if !u.DryRun {
-		u.cfg.Log("creating upgraded release for %s", name)
-		if err := u.cfg.Releases.Create(upgradedRelease); err != nil {
-			return nil, err
-		}
-	}
-
 	u.cfg.Log("performing update for %s", name)
 	res, err := u.performUpgrade(currentRelease, upgradedRelease)
 	if err != nil {
@@ -196,12 +190,6 @@ func (u *Upgrade) prepareUpgrade(name string, chart *chart.Chart, vals map[strin
 }
 
 func (u *Upgrade) performUpgrade(originalRelease, upgradedRelease *release.Release) (*release.Release, error) {
-	if u.DryRun {
-		u.cfg.Log("dry run for %s", upgradedRelease.Name)
-		upgradedRelease.Info.Description = "Dry run complete"
-		return upgradedRelease, nil
-	}
-
 	current, err := u.cfg.KubeClient.Build(bytes.NewBufferString(originalRelease.Manifest))
 	if err != nil {
 		return upgradedRelease, errors.Wrap(err, "unable to build kubernetes objects from current release manifest")
@@ -211,6 +199,34 @@ func (u *Upgrade) performUpgrade(originalRelease, upgradedRelease *release.Relea
 		return upgradedRelease, errors.Wrap(err, "unable to build kubernetes objects from new release manifest")
 	}
 
+	if u.DryRun {
+		u.cfg.Log("dry run for %s", upgradedRelease.Name)
+		upgradedRelease.Info.Description = "Dry run complete"
+		return upgradedRelease, nil
+	}
+
+	// Do a basic diff using gvk + name to figure out what new resources are being created so we can validate they don't already exist
+	existingResources := make(map[string]bool)
+	for _, r := range current {
+		existingResources[objectKey(r)] = true
+	}
+
+	var toBeCreated kube.ResourceList
+	for _, r := range target {
+		if !existingResources[objectKey(r)] {
+			toBeCreated = append(toBeCreated, r)
+		}
+	}
+
+	if err := existingResourceConflict(toBeCreated); err != nil {
+		return nil, errors.Wrap(err, "rendered manifests contain a new resource that already exists. Unable to continue with update")
+	}
+
+	u.cfg.Log("creating upgraded release for %s", upgradedRelease.Name)
+	if err := u.cfg.Releases.Create(upgradedRelease); err != nil {
+		return nil, err
+	}
+
 	// pre-upgrade hooks
 	if !u.DisableHooks {
 		if err := u.cfg.execHook(upgradedRelease, release.HookPreUpgrade, u.Timeout); err != nil {
@@ -396,3 +412,8 @@ func recreate(cfg *Configuration, resources kube.ResourceList) error {
 	}
 	return nil
 }
+
+func objectKey(r *resource.Info) string {
+	gvk := r.Object.GetObjectKind().GroupVersionKind()
+	return fmt.Sprintf("%s/%s/%s", gvk.GroupVersion().String(), gvk.Kind, r.Name)
+}

pkg/action/validate.go

@@ -0,0 +1,47 @@
+/*
+Copyright The Helm 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 action
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/cli-runtime/pkg/resource"
+
+	"helm.sh/helm/pkg/kube"
+)
+
+func existingResourceConflict(resources kube.ResourceList) error {
+	err := resources.Visit(func(info *resource.Info, err error) error {
+		if err != nil {
+			return err
+		}
+
+		helper := resource.NewHelper(info.Client, info.Mapping)
+		if _, err := helper.Get(info.Namespace, info.Name, info.Export); err != nil {
+			if apierrors.IsNotFound(err) {
+				return nil
+			}
+
+			return errors.Wrap(err, "could not get information about the resource")
+		}
+
+		return fmt.Errorf("existing resource conflict: kind: %s, namespace: %s, name: %s", info.Mapping.GroupVersionKind.Kind, info.Namespace, info.Name)
+	})
+	return err
+}

pkg/kube/client.go

@@ -191,7 +191,7 @@ func (c *Client) Update(original, target ResourceList, force bool) (*Result, err
 	for _, info := range original.Difference(target) {
 		c.Log("Deleting %q in %s...", info.Name, info.Namespace)
 		res.Deleted = append(res.Deleted, info)
-		if err := deleteResource(info); err != nil {
+		if err := deleteResource(info); err != nil && !apierrors.IsNotFound(err) {
 			c.Log("Failed to delete %q, err: %s", info.Name, err)
 			return res, errors.Wrapf(err, "Failed to delete %q", info.Name)
 		}