✨ feat: Accessing old object on watchEvent

docs/src/KUBERNETES.md

@@ -12,11 +12,11 @@ The path to the file is found in the `$KUBERNETES_PATCH_PATH` environment variab
 ### Create
 
 * `operation` — specifies an operation's type.
-    * `CreateOrUpdate` — accept a Kubernetes object.
+  * `CreateOrUpdate` — accept a Kubernetes object.
       It retrieves an object, and if it already exists, computes a JSON Merge Patch and applies it (will not update .status field).
       If it does not exist, we create the object.
-    * `Create` — will fail if an object already exists
-    * `CreateIfNotExists` — create an object if such an object does not already
+  * `Create` — will fail if an object already exists
+  * `CreateIfNotExists` — create an object if such an object does not already
       exist by namespace/name.
 * `object` — full object specification including "apiVersion", "kind" and all necessary metadata. Can be a normal JSON or YAML object or a stringified JSON or YAML object.
 
@@ -25,6 +25,54 @@ The path to the file is found in the `$KUBERNETES_PATCH_PATH` environment variab
 ```json
 {
   "operation": "CreateOrUpdate",
+  "oldObject": {
+    "apiVersion": "apps/v1",
+    "kind": "DaemonSet",
+    "metadata": {
+      "name": "flannel",
+      "namespace": "d8-flannel"
+    },
+    "spec": {
+      "selector": {
+        "matchLabels": {
+          "app": "flannel"
+        }
+      },
+      "template": {
+        "metadata": {
+          "labels": {
+            "app": "flannel",
+            "tier": "old-node"
+          }
+        },
+        "spec": {
+          "containers": [
+            {
+              "args": [
+                "--ip-masq",
+                "--kube-subnet-mgr"
+              ],
+              "image": "flannel:v0.11",
+              "name": "kube-flannel",
+              "securityContext": {
+                "privileged": true
+              }
+            }
+          ],
+          "hostNetwork": true,
+          "imagePullSecrets": [
+            {
+              "name": "registry"
+            }
+          ],
+          "terminationGracePeriodSeconds": 5
+        }
+      },
+      "updateStrategy": {
+        "type": "RollingUpdate"
+      }
+    }
+  },
   "object": {
     "apiVersion": "apps/v1",
     "kind": "DaemonSet",
@@ -123,7 +171,7 @@ object: |
 
 ### Patch
 
-Use `JQPatch` for almost everything. Consider using `MergePatch` or `JSONPatch` if you are attempting to modify 
+Use `JQPatch` for almost everything. Consider using `MergePatch` or `JSONPatch` if you are attempting to modify
 rapidly changing object, for example `status` field with many concurrent changes (and incrementing `resourceVersion`).
 
 Be careful, when updating a `.status` field. If a `/status` subresource is enabled on a resource,
@@ -140,6 +188,7 @@ More info [here][spec-and-status].
 * `name` — object's name.
 * `jqFilter` — describes transformations to perform on an object.
 * `subresource` — a subresource name if subresource is to be transformed. For example, `status`.
+
 ##### Example
 
 ```json

pkg/kube_events_manager/resource_informer.go

@@ -266,22 +266,22 @@ func (ei *resourceInformer) LoadExistedObjects() error {
 }
 
 func (ei *resourceInformer) OnAdd(obj interface{}) {
-	ei.HandleWatchEvent(obj, WatchEventAdded)
+	ei.HandleWatchEvent(nil, obj, WatchEventAdded)
 }
 
-func (ei *resourceInformer) OnUpdate(_, newObj interface{}) {
-	ei.HandleWatchEvent(newObj, WatchEventModified)
+func (ei *resourceInformer) OnUpdate(oldObj, newObj interface{}) {
+	ei.HandleWatchEvent(oldObj, newObj, WatchEventModified)
 }
 
 func (ei *resourceInformer) OnDelete(obj interface{}) {
-	ei.HandleWatchEvent(obj, WatchEventDeleted)
+	ei.HandleWatchEvent(nil, obj, WatchEventDeleted)
 }
 
 // HandleKubeEvent register object in cache. Pass object to callback if object's checksum is changed.
 // TODO refactor: pass KubeEvent as argument
 // TODO add delay to merge Added and Modified events (node added and then labels applied — one hook run on Added+Modified is enough)
 // func (ei *resourceInformer) HandleKubeEvent(obj *unstructured.Unstructured, objectId string, filterResult string, newChecksum string, eventType WatchEventType) {
-func (ei *resourceInformer) HandleWatchEvent(object interface{}, eventType WatchEventType) {
+func (ei *resourceInformer) HandleWatchEvent(oldObject, object interface{}, eventType WatchEventType) {
 	// check if stop
 	if ei.stopped {
 		return
@@ -297,6 +297,11 @@ func (ei *resourceInformer) HandleWatchEvent(object interface{}, eventType Watch
 	}
 	obj := object.(*unstructured.Unstructured)
 
+	var oldObj *unstructured.Unstructured
+	if oldObject != nil {
+		oldObj = oldObject.(*unstructured.Unstructured)
+  }
+
 	resourceId := ResourceId(obj)
 
 	// Always calculate checksum and update cache, because we need an actual state in ei.cachedObjects.
@@ -319,6 +324,10 @@ func (ei *resourceInformer) HandleWatchEvent(object interface{}, eventType Watch
 
 	if !ei.Monitor.KeepFullObjectsInMemory {
 		objFilterRes.RemoveFullObject()
+	} else if ei.Monitor.KeepFullObjectsInMemory {
+		if oldObj != nil {
+			objFilterRes.OldObject = oldObj
+		}
 	}
 
 	// Do not fire Added or Modified if object is in cache and its checksum is equal to the newChecksum.

pkg/kube_events_manager/types/types.go

@@ -41,6 +41,7 @@ type ObjectAndFilterResult struct {
 		RemoveObject bool
 	}
 	Object       *unstructured.Unstructured // here is a pointer because of MarshalJSON receiver
+	OldObject    *unstructured.Unstructured // here is a pointer because of MarshalJSON receiver and also it's nullable for some events
 	FilterResult interface{}
 }