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Merge pull request #1413 from timebertt/enh/strategic-merge-patch-0.8
✨ [release-0.8] Add client.StrategicMergeFrom
2 parents 12660d4 + f5c6519 commit c7e9da4

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pkg/client/client_test.go

Lines changed: 79 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3240,7 +3240,7 @@ var _ = Describe("DelegatingClient", func() {
32403240
})
32413241

32423242
var _ = Describe("Patch", func() {
3243-
Describe("CreateMergePatch", func() {
3243+
Describe("MergeFrom", func() {
32443244
var cm *corev1.ConfigMap
32453245

32463246
BeforeEach(func() {
@@ -3303,6 +3303,84 @@ var _ = Describe("Patch", func() {
33033303
Expect(data).To(Equal([]byte(fmt.Sprintf(`{"metadata":{"annotations":{"%s":"%s"},"resourceVersion":"%s"}}`, annotationKey, annotationValue, cm.ResourceVersion))))
33043304
})
33053305
})
3306+
3307+
Describe("StrategicMergeFrom", func() {
3308+
var dep *appsv1.Deployment
3309+
3310+
BeforeEach(func() {
3311+
dep = &appsv1.Deployment{
3312+
ObjectMeta: metav1.ObjectMeta{
3313+
Namespace: metav1.NamespaceDefault,
3314+
Name: "dep",
3315+
ResourceVersion: "10",
3316+
},
3317+
Spec: appsv1.DeploymentSpec{
3318+
Template: corev1.PodTemplateSpec{
3319+
Spec: corev1.PodSpec{Containers: []corev1.Container{{
3320+
Name: "main",
3321+
Image: "foo:v1",
3322+
}, {
3323+
Name: "sidecar",
3324+
Image: "bar:v1",
3325+
}}},
3326+
},
3327+
},
3328+
}
3329+
})
3330+
3331+
It("creates a strategic merge patch with the modifications applied during the mutation", func() {
3332+
By("creating a strategic merge patch")
3333+
patch := client.StrategicMergeFrom(dep.DeepCopy())
3334+
3335+
By("returning a patch with type StrategicMergePatchType")
3336+
Expect(patch.Type()).To(Equal(types.StrategicMergePatchType))
3337+
3338+
By("updating the main container's image")
3339+
for i, c := range dep.Spec.Template.Spec.Containers {
3340+
if c.Name == "main" {
3341+
c.Image = "foo:v2"
3342+
}
3343+
dep.Spec.Template.Spec.Containers[i] = c
3344+
}
3345+
3346+
By("computing the patch data")
3347+
data, err := patch.Data(dep)
3348+
3349+
By("returning no error")
3350+
Expect(err).NotTo(HaveOccurred())
3351+
3352+
By("returning a patch with data only containing the image change")
3353+
Expect(data).To(Equal([]byte(`{"spec":{"template":{"spec":{"$setElementOrder/containers":[{"name":"main"},` +
3354+
`{"name":"sidecar"}],"containers":[{"image":"foo:v2","name":"main"}]}}}}`)))
3355+
})
3356+
3357+
It("creates a strategic merge patch with the modifications applied during the mutation, using optimistic locking", func() {
3358+
By("creating a strategic merge patch")
3359+
patch := client.StrategicMergeFrom(dep.DeepCopy(), client.MergeFromWithOptimisticLock{})
3360+
3361+
By("returning a patch with type StrategicMergePatchType")
3362+
Expect(patch.Type()).To(Equal(types.StrategicMergePatchType))
3363+
3364+
By("updating the main container's image")
3365+
for i, c := range dep.Spec.Template.Spec.Containers {
3366+
if c.Name == "main" {
3367+
c.Image = "foo:v2"
3368+
}
3369+
dep.Spec.Template.Spec.Containers[i] = c
3370+
}
3371+
3372+
By("computing the patch data")
3373+
data, err := patch.Data(dep)
3374+
3375+
By("returning no error")
3376+
Expect(err).NotTo(HaveOccurred())
3377+
3378+
By("returning a patch with data containing the image change and the resourceVersion change")
3379+
Expect(data).To(Equal([]byte(fmt.Sprintf(`{"metadata":{"resourceVersion":"%s"},`+
3380+
`"spec":{"template":{"spec":{"$setElementOrder/containers":[{"name":"main"},{"name":"sidecar"}],"containers":[{"image":"foo:v2","name":"main"}]}}}}`,
3381+
dep.ResourceVersion))))
3382+
})
3383+
})
33063384
})
33073385

33083386
var _ = Describe("IgnoreNotFound", func() {

pkg/client/patch.go

Lines changed: 41 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -25,6 +25,7 @@ import (
2525
"k8s.io/apimachinery/pkg/runtime"
2626
"k8s.io/apimachinery/pkg/types"
2727
"k8s.io/apimachinery/pkg/util/json"
28+
"k8s.io/apimachinery/pkg/util/strategicpatch"
2829
)
2930

3031
var (
@@ -87,13 +88,15 @@ type MergeFromOptions struct {
8788
}
8889

8990
type mergeFromPatch struct {
90-
from runtime.Object
91-
opts MergeFromOptions
91+
patchType types.PatchType
92+
createPatch func(originalJSON, modifiedJSON []byte, dataStruct interface{}) ([]byte, error)
93+
from runtime.Object
94+
opts MergeFromOptions
9295
}
9396

9497
// Type implements patch.
9598
func (s *mergeFromPatch) Type() types.PatchType {
96-
return types.MergePatchType
99+
return s.patchType
97100
}
98101

99102
// Data implements Patch.
@@ -108,7 +111,7 @@ func (s *mergeFromPatch) Data(obj runtime.Object) ([]byte, error) {
108111
return nil, err
109112
}
110113

111-
data, err := jsonpatch.CreateMergePatch(originalJSON, modifiedJSON)
114+
data, err := s.createPatch(originalJSON, modifiedJSON, obj)
112115
if err != nil {
113116
return nil, err
114117
}
@@ -137,18 +140,50 @@ func (s *mergeFromPatch) Data(obj runtime.Object) ([]byte, error) {
137140
return data, nil
138141
}
139142

143+
func createMergePatch(originalJSON, modifiedJSON []byte, _ interface{}) ([]byte, error) {
144+
return jsonpatch.CreateMergePatch(originalJSON, modifiedJSON)
145+
}
146+
147+
func createStrategicMergePatch(originalJSON, modifiedJSON []byte, dataStruct interface{}) ([]byte, error) {
148+
return strategicpatch.CreateTwoWayMergePatch(originalJSON, modifiedJSON, dataStruct)
149+
}
150+
140151
// MergeFrom creates a Patch that patches using the merge-patch strategy with the given object as base.
152+
// The difference between MergeFrom and StrategicMergeFrom lays in the handling of modified list fields.
153+
// When using MergeFrom, existing lists will be completely replaced by new lists.
154+
// When using StrategicMergeFrom, the list field's `patchStrategy` is respected if specified in the API type,
155+
// e.g. the existing list is not replaced completely but rather merged with the new one using the list's `patchMergeKey`.
156+
// See https://kubernetes.io/docs/tasks/manage-kubernetes-objects/update-api-object-kubectl-patch/ for more details on
157+
// the difference between merge-patch and strategic-merge-patch.
141158
func MergeFrom(obj runtime.Object) Patch {
142-
return &mergeFromPatch{from: obj}
159+
return &mergeFromPatch{patchType: types.MergePatchType, createPatch: createMergePatch, from: obj}
143160
}
144161

145162
// MergeFromWithOptions creates a Patch that patches using the merge-patch strategy with the given object as base.
163+
// See MergeFrom for more details.
146164
func MergeFromWithOptions(obj runtime.Object, opts ...MergeFromOption) Patch {
147165
options := &MergeFromOptions{}
148166
for _, opt := range opts {
149167
opt.ApplyToMergeFrom(options)
150168
}
151-
return &mergeFromPatch{from: obj, opts: *options}
169+
return &mergeFromPatch{patchType: types.MergePatchType, createPatch: createMergePatch, from: obj, opts: *options}
170+
}
171+
172+
// StrategicMergeFrom creates a Patch that patches using the strategic-merge-patch strategy with the given object as base.
173+
// The difference between MergeFrom and StrategicMergeFrom lays in the handling of modified list fields.
174+
// When using MergeFrom, existing lists will be completely replaced by new lists.
175+
// When using StrategicMergeFrom, the list field's `patchStrategy` is respected if specified in the API type,
176+
// e.g. the existing list is not replaced completely but rather merged with the new one using the list's `patchMergeKey`.
177+
// See https://kubernetes.io/docs/tasks/manage-kubernetes-objects/update-api-object-kubectl-patch/ for more details on
178+
// the difference between merge-patch and strategic-merge-patch.
179+
// Please note, that CRDs don't support strategic-merge-patch, see
180+
// https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/#advanced-features-and-flexibility
181+
func StrategicMergeFrom(obj Object, opts ...MergeFromOption) Patch {
182+
options := &MergeFromOptions{}
183+
for _, opt := range opts {
184+
opt.ApplyToMergeFrom(options)
185+
}
186+
return &mergeFromPatch{patchType: types.StrategicMergePatchType, createPatch: createStrategicMergePatch, from: obj, opts: *options}
152187
}
153188

154189
// mergePatch uses a raw merge strategy to patch the object.

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