applylib: combine field managers

This ensures that we don't lose managed fields as we update them.

go.mod

@@ -57,6 +57,7 @@ require (
 	helm.sh/helm/v3 v3.10.2
 	k8s.io/api v0.25.4
 	k8s.io/apimachinery v0.25.4
+	k8s.io/apiserver v0.25.4
 	k8s.io/cli-runtime v0.25.4
 	k8s.io/client-go v0.25.4
 	k8s.io/cloud-provider-aws v1.25.1
@@ -69,6 +70,7 @@ require (
 	k8s.io/mount-utils v0.25.4
 	k8s.io/utils v0.0.0-20221108210102-8e77b1f39fe2
 	sigs.k8s.io/controller-runtime v0.13.1
+	sigs.k8s.io/structured-merge-diff/v4 v4.2.3
 	sigs.k8s.io/yaml v1.3.0
 )
 
@@ -248,5 +250,4 @@ require (
 	sigs.k8s.io/json v0.0.0-20220713155537-f223a00ba0e2 // indirect
 	sigs.k8s.io/kustomize/api v0.12.1 // indirect
 	sigs.k8s.io/kustomize/kyaml v0.13.9 // indirect
-	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
 )

go.sum

@@ -1345,6 +1345,8 @@ k8s.io/apiextensions-apiserver v0.25.2 h1:8uOQX17RE7XL02ngtnh3TgifY7EhekpK+/piwz
 k8s.io/apiextensions-apiserver v0.25.2/go.mod h1:iRwwRDlWPfaHhuBfQ0WMa5skdQfrE18QXJaJvIDLvE8=
 k8s.io/apimachinery v0.25.4 h1:CtXsuaitMESSu339tfhVXhQrPET+EiWnIY1rcurKnAc=
 k8s.io/apimachinery v0.25.4/go.mod h1:jaF9C/iPNM1FuLl7Zuy5b9v+n35HGSh6AQ4HYRkCqwo=
+k8s.io/apiserver v0.25.4 h1:/3TwZcgLqX7wUxq7TtXOUqXeBTwXIblVMQdhR5XZ7yo=
+k8s.io/apiserver v0.25.4/go.mod h1:rPcm567XxjOnnd7jedDUnGJGmDGAo+cT6H7QHAN+xV0=
 k8s.io/cli-runtime v0.25.4 h1:GTSBN7aKBrc2LqpdO30CmHQqJtRmotxV7XsMSP+QZIk=
 k8s.io/cli-runtime v0.25.4/go.mod h1:JGOw1CR8v4Mcz6cEKA7bFQe0bPrNn1l5sGAX1/Ke4Eg=
 k8s.io/client-go v0.25.4 h1:3RNRDffAkNU56M/a7gUfXaEzdhZlYhoW8dgViGy5fn8=

pkg/applylib/applyset/applyset.go

@@ -22,11 +22,9 @@ import (
 	"fmt"
 	"sync"
 
-	"k8s.io/apimachinery/pkg/api/errors"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/client-go/dynamic"
 )
@@ -102,6 +100,11 @@ func (a *ApplySet) ApplyOnce(ctx context.Context) (*ApplyResults, error) {
 	trackers := a.trackers
 	a.mutex.Unlock()
 
+	client := &UnstructuredClient{
+		client:     a.client,
+		restMapper: a.restMapper,
+	}
+
 	results := &ApplyResults{total: len(trackers.items)}
 
 	for i := range trackers.items {
@@ -113,54 +116,28 @@ func (a *ApplySet) ApplyOnce(ctx context.Context) (*ApplyResults, error) {
 		gvk := expectedObject.GroupVersionKind()
 		nn := types.NamespacedName{Namespace: ns, Name: name}
 
-		restMapping, err := a.restMapper.RESTMapping(gvk.GroupKind(), gvk.Version)
+		currentObj, err := client.Get(ctx, gvk, nn)
 		if err != nil {
-			results.applyError(gvk, nn, fmt.Errorf("error getting rest mapping for %v: %w", gvk, err))
+			if !apierrors.IsNotFound(err) {
+				results.applyError(gvk, nn, err)
 				continue
 			}
-		gvr := restMapping.Resource
+		}
 
-		var dynamicResource dynamic.ResourceInterface
+		// If the object exists, we need to update any client-side-apply field-managers
-
+		// Otherwise we often end up with old and new objects combined, which
-		switch restMapping.Scope.Name() {
+		// is unexpected and can be invalid.
-		case meta.RESTScopeNameNamespace:
+		if currentObj != nil {
-			if ns == "" {
+			managedFields := &ManagedFieldsMigrator{
-				// TODO: Differentiate between server-fixable vs client-fixable errors?
+				NewManager: "kops",
-				results.applyError(gvk, nn, fmt.Errorf("namespace was not provided for namespace-scoped object %v", gvk))
+				Client:     client,
+			}
+			if err := managedFields.Migrate(ctx, currentObj); err != nil {
+				results.applyError(gvk, nn, err)
 				continue
 			}
-			dynamicResource = a.client.Resource(gvr).Namespace(ns)
-
-		case meta.RESTScopeNameRoot:
-			if ns != "" {
-				// TODO: Differentiate between server-fixable vs client-fixable errors?
-				results.applyError(gvk, nn, fmt.Errorf("namespace %q was provided for cluster-scoped object %v", expectedObject.GetNamespace(), gvk))
-				continue
-			}
-			dynamicResource = a.client.Resource(gvr)
-
-		default:
-			// Internal error ... this is panic-level
-			return nil, fmt.Errorf("unknown scope for gvk %s: %q", gvk, restMapping.Scope.Name())
 		}
 
-		currentObj, err := dynamicResource.Get(ctx, name, v1.GetOptions{})
-		if err != nil {
-			if !errors.IsNotFound(err) {
-				return nil, fmt.Errorf("could not get existing object: %w", err)
-			}
-		}
-		jsonData, err := createManagedFieldPatch(currentObj)
-		if err != nil {
-			return nil, fmt.Errorf("failed to create json patch: %w", err)
-		}
-
-		if jsonData != nil {
-			_, err := dynamicResource.Patch(ctx, name, types.MergePatchType, jsonData, v1.PatchOptions{})
-			if err != nil {
-				return nil, fmt.Errorf("failed to patch object %q: %w", name, err)
-			}
-		}
 		j, err := json.Marshal(expectedObject)
 		if err != nil {
 			// TODO: Differentiate between server-fixable vs client-fixable errors?
@@ -168,7 +145,7 @@ func (a *ApplySet) ApplyOnce(ctx context.Context) (*ApplyResults, error) {
 			continue
 		}
 
-		lastApplied, err := dynamicResource.Patch(ctx, name, types.ApplyPatchType, j, a.patchOptions)
+		lastApplied, err := client.Patch(ctx, gvk, nn, types.ApplyPatchType, j, a.patchOptions)
 		if err != nil {
 			results.applyError(gvk, nn, fmt.Errorf("error from apply: %w", err))
 			continue
@@ -181,36 +158,3 @@ func (a *ApplySet) ApplyOnce(ctx context.Context) (*ApplyResults, error) {
 	}
 	return results, nil
 }
-
-func createManagedFieldPatch(currentObject *unstructured.Unstructured) ([]byte, error) {
-	if currentObject == nil {
-		return nil, nil
-	}
-	fixedManagedFields := []v1.ManagedFieldsEntry{}
-	for _, managedField := range currentObject.GetManagedFields() {
-		fixedManagedField := managedField.DeepCopy()
-		if managedField.Manager == "kubectl-edit" || managedField.Manager == "kubectl-client-side-apply" {
-			fixedManagedField.Manager = "kops"
-			fixedManagedField.Operation = "Apply"
-		}
-		// In case we have a kops & Update manager
-		if fixedManagedField.Manager == "kops" && fixedManagedField.Operation == "Update" {
-			fixedManagedField.Operation = "Apply"
-		}
-		fixedManagedFields = append(fixedManagedFields, *fixedManagedField)
-	}
-	if len(fixedManagedFields) == 0 {
-		return nil, nil
-	}
-	meta := &v1.ObjectMeta{}
-	meta.SetManagedFields(fixedManagedFields)
-	patchObject := map[string]interface{}{
-		"metadata": meta,
-	}
-
-	jsonData, err := json.Marshal(patchObject)
-	if err != nil {
-		return nil, fmt.Errorf("failed to marsal %q into json: %w", currentObject.GetName(), err)
-	}
-	return jsonData, nil
-}

pkg/applylib/applyset/managedfields.go

@@ -0,0 +1,182 @@
+/*
+Copyright 2022 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 applyset
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager"
+	"sigs.k8s.io/structured-merge-diff/v4/fieldpath"
+)
+
+// ManagedFieldsMigrator manages the migration of field managers from client-side managers to the server-side manager.
+type ManagedFieldsMigrator struct {
+	Client     *UnstructuredClient
+	NewManager string
+}
+
+// Migrate migrates from client-side field managers to the NewManager (with an Apply operation).
+// This is needed to move from client-side apply to server-side apply.
+func (m *ManagedFieldsMigrator) Migrate(ctx context.Context, obj *unstructured.Unstructured) error {
+	managedFieldPatch, err := m.createManagedFieldPatch(obj)
+	if err != nil {
+		return fmt.Errorf("failed to create managed-fields patch: %w", err)
+	}
+	if managedFieldPatch != nil {
+		gvk := obj.GroupVersionKind()
+		nn := types.NamespacedName{Namespace: obj.GetNamespace(), Name: obj.GetName()}
+		_, err := m.Client.Patch(ctx, gvk, nn, types.MergePatchType, managedFieldPatch, metav1.PatchOptions{})
+		if err != nil {
+			return fmt.Errorf("failed to patch object managed-fields for %q: %w", obj.GetName(), err)
+		}
+	}
+	return nil
+}
+
+// createManagedFieldPatch constructs a patch to combine managed fields.
+// It returns nil if no patch is needed.
+func (m *ManagedFieldsMigrator) createManagedFieldPatch(currentObject *unstructured.Unstructured) ([]byte, error) {
+	if currentObject == nil {
+		return nil, nil
+	}
+	needPatch := false
+	fixedManagedFields := []metav1.ManagedFieldsEntry{}
+	for _, managedField := range currentObject.GetManagedFields() {
+		fixedManagedField := managedField.DeepCopy()
+		if managedField.Manager == "kubectl-edit" || managedField.Manager == "kubectl-client-side-apply" {
+			needPatch = true
+			fixedManagedField.Manager = m.NewManager
+			fixedManagedField.Operation = metav1.ManagedFieldsOperationApply
+		}
+		// In case we have an existing Update operation
+		if fixedManagedField.Manager == m.NewManager && fixedManagedField.Operation == "Update" {
+			needPatch = true
+			fixedManagedField.Operation = metav1.ManagedFieldsOperationApply
+		}
+		fixedManagedFields = append(fixedManagedFields, *fixedManagedField)
+	}
+	if !needPatch {
+		return nil, nil
+	}
+
+	merged, err := mergeFieldManagers(fixedManagedFields)
+	if err != nil {
+		return nil, err
+	}
+	fixedManagedFields = merged
+
+	meta := &metav1.ObjectMeta{}
+	meta.SetManagedFields(fixedManagedFields)
+	patchObject := map[string]interface{}{
+		"metadata": meta,
+	}
+
+	jsonData, err := json.Marshal(patchObject)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marsal %q into json: %w", currentObject.GetName(), err)
+	}
+	return jsonData, nil
+}
+
+// fieldManagerKey is the primary key for a ManagedFieldEntry
+type fieldManagerKey struct {
+	Manager     string
+	Operation   metav1.ManagedFieldsOperationType
+	Subresource string
+}
+
+// mergeFieldManagers merges the managed fields from identical field managers.
+// If we don't do this, the apiserver will not currently construct the union for duplicate keys.
+func mergeFieldManagers(managedFields []metav1.ManagedFieldsEntry) ([]metav1.ManagedFieldsEntry, error) {
+	byKey := make(map[fieldManagerKey][]metav1.ManagedFieldsEntry)
+	for _, f := range managedFields {
+		k := fieldManagerKey{
+			Manager:     f.Manager,
+			Operation:   f.Operation,
+			Subresource: f.Subresource,
+		}
+
+		byKey[k] = append(byKey[k], f)
+	}
+
+	var result []metav1.ManagedFieldsEntry
+	for k := range byKey {
+		managers := byKey[k]
+		if len(managers) > 1 {
+			fieldSet, err := mergeManagedFields(managers)
+			if err != nil {
+				return nil, err
+			}
+			encoded, err := fieldSet.ToJSON()
+			if err != nil {
+				return nil, err
+			}
+			managers[0].FieldsV1.Raw = encoded
+		}
+		result = append(result, managers[0])
+	}
+	return result, nil
+}
+
+// mergeManagedFields merges a set of ManagedFieldEntry managed fields, that are expected to have the same key.
+func mergeManagedFields(managedFields []metav1.ManagedFieldsEntry) (*fieldpath.Set, error) {
+	if len(managedFields) == 0 {
+		return nil, fmt.Errorf("no managed fields supplied")
+	}
+
+	union, err := toFieldPathSet(&managedFields[0])
+	if err != nil {
+		return nil, err
+	}
+
+	for i := range managedFields {
+		if i == 0 {
+			continue
+		}
+		m := &managedFields[i]
+		if managedFields[0].APIVersion != m.APIVersion {
+			return nil, fmt.Errorf("cannot merge ManagedFieldsEntry apiVersion %q with apiVersion %q", managedFields[0].APIVersion, m.APIVersion)
+		}
+
+		set, err := toFieldPathSet(m)
+		if err != nil {
+			return nil, err
+		}
+		union = union.Union(set)
+	}
+	return union, nil
+}
+
+// toFieldPathSet converts an encoded ManagedFieldsEntry to a set of managed fields (a fieldpath.Set)
+func toFieldPathSet(fields *metav1.ManagedFieldsEntry) (*fieldpath.Set, error) {
+	decoded, err := fieldmanager.DecodeManagedFields([]metav1.ManagedFieldsEntry{*fields})
+	if err != nil {
+		return nil, err
+	}
+	if len(decoded.Fields()) != 1 {
+		return nil, fmt.Errorf("expected a single managed fields entry, but got %d", len(decoded.Fields()))
+	}
+	for _, fieldSet := range decoded.Fields() {
+		return fieldSet.Set(), nil
+	}
+	return nil, fmt.Errorf("no fields were decoded")
+}

pkg/applylib/applyset/unstructuredclient.go

@@ -0,0 +1,122 @@
+/*
+Copyright 2022 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 applyset
+
+import (
+	"context"
+	"fmt"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/client-go/dynamic"
+)
+
+// UnstructuredClient is a client that makes it easier to work with unstructured objects.
+// It is similar to client.Client in controller-runtime, but is never cached.
+type UnstructuredClient struct {
+	// client is the dynamic kubernetes client used to apply objects to the k8s cluster.
+	client dynamic.Interface
+	// restMapper is used to map object kind to resources, and to know if objects are cluster-scoped.
+	restMapper meta.RESTMapper
+}
+
+// NewUnstructuredClient constructs an UnstructuredClient
+func NewUnstructuredClient(options Options) *UnstructuredClient {
+	return &UnstructuredClient{
+		client:     options.Client,
+		restMapper: options.RESTMapper,
+	}
+}
+
+// dynamicResource is a helper to get the resource for a gvk (with the namespace)
+// It returns an error if a namespace is provided for a cluster-scoped resource,
+// or no namespace is provided for a namespace-scoped resource.
+func (c *UnstructuredClient) dynamicResource(ctx context.Context, gvk schema.GroupVersionKind, ns string) (dynamic.ResourceInterface, error) {
+	restMapping, err := c.restMapper.RESTMapping(gvk.GroupKind(), gvk.Version)
+	if err != nil {
+		return nil, fmt.Errorf("error getting rest mapping for %v: %w", gvk, err)
+	}
+	gvr := restMapping.Resource
+
+	switch restMapping.Scope.Name() {
+	case meta.RESTScopeNameNamespace:
+		if ns == "" {
+			// TODO: Differentiate between server-fixable vs client-fixable errors?
+			return nil, fmt.Errorf("namespace was not provided for namespace-scoped object %v", gvk)
+		}
+		return c.client.Resource(gvr).Namespace(ns), nil
+
+	case meta.RESTScopeNameRoot:
+		if ns != "" {
+			// TODO: Differentiate between server-fixable vs client-fixable errors?
+			return nil, fmt.Errorf("namespace %q was provided for cluster-scoped object %v", ns, gvk)
+		}
+		return c.client.Resource(gvr), nil
+
+	default:
+		// Internal error ... this is panic-level
+		return nil, fmt.Errorf("unknown scope for gvk %s: %q", gvk, restMapping.Scope.Name())
+	}
+}
+
+// Patch performs a Patch operation, used for server-side apply and client-side patch.
+func (c *UnstructuredClient) Patch(ctx context.Context, gvk schema.GroupVersionKind, nn types.NamespacedName, patchType types.PatchType, data []byte, opt metav1.PatchOptions) (*unstructured.Unstructured, error) {
+	dynamicResource, err := c.dynamicResource(ctx, gvk, nn.Namespace)
+	if err != nil {
+		return nil, err
+	}
+
+	name := nn.Name
+	patched, err := dynamicResource.Patch(ctx, name, patchType, data, opt)
+	if err != nil {
+		return nil, fmt.Errorf("error patching object: %w", err)
+	}
+	return patched, nil
+}
+
+// Update performs an Update operation on the object.  Generally we should prefer server-side-apply.
+func (c *UnstructuredClient) Update(ctx context.Context, obj *unstructured.Unstructured, opt metav1.UpdateOptions) (*unstructured.Unstructured, error) {
+	gvk := obj.GroupVersionKind()
+	dynamicResource, err := c.dynamicResource(ctx, gvk, obj.GetNamespace())
+	if err != nil {
+		return nil, err
+	}
+
+	updated, err := dynamicResource.Update(ctx, obj, opt)
+	if err != nil {
+		return nil, fmt.Errorf("error updating object: %w", err)
+	}
+	return updated, nil
+}
+
+// Get reads the specified object.
+func (c *UnstructuredClient) Get(ctx context.Context, gvk schema.GroupVersionKind, nn types.NamespacedName) (*unstructured.Unstructured, error) {
+	dynamicResource, err := c.dynamicResource(ctx, gvk, nn.Namespace)
+	if err != nil {
+		return nil, err
+	}
+
+	obj, err := dynamicResource.Get(ctx, nn.Name, metav1.GetOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("could not get existing object: %w", err)
+	}
+
+	return obj, nil
+}