From 206cd7787ff0cc0c8962ef9e4f21c45df85969e9 Mon Sep 17 00:00:00 2001
From: Kajol Asabe <114986456+kasabe28@users.noreply.github.com>
Date: Mon, 4 Mar 2024 14:10:33 +0530
Subject: [PATCH] Add `ResourceVersion` to internal `Machine` type (#191)

Co-authored-by: Lukas Koszegy <l.koszegy@gmail.com>
---
 pkg/api/api.go     | 17 ++++++++++++++---
 pkg/host/store.go  |  9 ++++++++-
 pkg/store/store.go |  5 +++--
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/pkg/api/api.go b/pkg/api/api.go
index e1aac7ce..5c64cfb0 100644
--- a/pkg/api/api.go
+++ b/pkg/api/api.go
@@ -10,9 +10,10 @@ type Metadata struct {
 	Annotations map[string]string `json:"annotations"`
 	Labels      map[string]string `json:"labels"`
 
-	CreatedAt  time.Time  `json:"createdAt"`
-	DeletedAt  *time.Time `json:"deletedAt,omitempty"`
-	Generation int64      `json:"generation"`
+	CreatedAt       time.Time  `json:"createdAt"`
+	DeletedAt       *time.Time `json:"deletedAt,omitempty"`
+	Generation      int64      `json:"generation"`
+	ResourceVersion uint64     `json:"resourceVersion"`
 
 	Finalizers []string `json:"finalizers,omitempty"`
 }
@@ -45,6 +46,10 @@ func (m *Metadata) GetFinalizers() []string {
 	return m.Finalizers
 }
 
+func (m *Metadata) GetResourceVersion() uint64 {
+	return m.ResourceVersion
+}
+
 func (m *Metadata) SetID(id string) {
 	m.ID = id
 }
@@ -73,6 +78,10 @@ func (m *Metadata) SetFinalizers(finalizers []string) {
 	m.Finalizers = finalizers
 }
 
+func (m *Metadata) IncrementResourceVersion() {
+	m.ResourceVersion++
+}
+
 type Object interface {
 	GetID() string
 	GetAnnotations() map[string]string
@@ -81,6 +90,7 @@ type Object interface {
 	GetDeletedAt() *time.Time
 	GetGeneration() int64
 	GetFinalizers() []string
+	GetResourceVersion() uint64
 
 	SetID(id string)
 	SetAnnotations(annotations map[string]string)
@@ -89,4 +99,5 @@ type Object interface {
 	SetDeletedAt(deleted *time.Time)
 	SetGeneration(generation int64)
 	SetFinalizers(finalizers []string)
+	IncrementResourceVersion()
 }
diff --git a/pkg/host/store.go b/pkg/host/store.go
index 4ccc6baa..1450e7a2 100644
--- a/pkg/host/store.go
+++ b/pkg/host/store.go
@@ -86,6 +86,7 @@ func (s *Store[E]) Create(_ context.Context, obj E) (E, error) {
 	}
 
 	obj.SetCreatedAt(time.Now())
+	obj.IncrementResourceVersion()
 
 	obj, err = s.set(obj)
 	if err != nil {
@@ -128,11 +129,16 @@ func (s *Store[E]) Update(_ context.Context, obj E) (E, error) {
 		return obj, nil
 	}
 
+	if oldObj.GetResourceVersion() != obj.GetResourceVersion() {
+		return utils.Zero[E](), fmt.Errorf("failed to update object: %w", store.ErrResourceVersionNotLatest)
+	}
+
 	if reflect.DeepEqual(oldObj, obj) {
 		return obj, nil
 	}
 
-	//Todo: update version
+	obj.IncrementResourceVersion()
+
 	obj, err = s.set(obj)
 	if err != nil {
 		return utils.Zero[E](), err
@@ -161,6 +167,7 @@ func (s *Store[E]) Delete(_ context.Context, id string) error {
 
 	now := time.Now()
 	obj.SetDeletedAt(&now)
+	obj.IncrementResourceVersion()
 
 	if _, err := s.set(obj); err != nil {
 		return fmt.Errorf("failed to set object metadata: %w", err)
diff --git a/pkg/store/store.go b/pkg/store/store.go
index 4a5e0b49..5c52b761 100644
--- a/pkg/store/store.go
+++ b/pkg/store/store.go
@@ -11,8 +11,9 @@ import (
 )
 
 var (
-	ErrNotFound      = errors.New("not found")
-	ErrAlreadyExists = errors.New("already exists")
+	ErrNotFound                 = errors.New("not found")
+	ErrAlreadyExists            = errors.New("already exists")
+	ErrResourceVersionNotLatest = errors.New("resourceVersion is not latest")
 )
 
 func IgnoreErrNotFound(err error) error {