From 321058915b26ea70f9d5a3a19109de0accef6357 Mon Sep 17 00:00:00 2001
From: Justin Kulikauskas <jkulikau@redhat.com>
Date: Wed, 8 May 2024 17:02:06 -0400
Subject: [PATCH] WIP: next

---
 api/v1beta1/policycore_types.go   |  24 +++++++
 pkg/compliance/k8sEventEmitter.go | 103 ++++++++++++++++++++++++++++++
 2 files changed, 127 insertions(+)
 create mode 100644 pkg/compliance/k8sEventEmitter.go

diff --git a/api/v1beta1/policycore_types.go b/api/v1beta1/policycore_types.go
index 2acde7a..5f04edd 100644
--- a/api/v1beta1/policycore_types.go
+++ b/api/v1beta1/policycore_types.go
@@ -193,3 +193,27 @@ type PolicyCore struct {
 	Spec   PolicyCoreSpec   `json:"spec,omitempty"`
 	Status PolicyCoreStatus `json:"status,omitempty"`
 }
+
+//+kubebuilder:object:generate=false
+
+// PolicyLike is an interface that policies should implement so that they can be worked with
+// generically, without worrying about the specific kind of policy.
+type PolicyLike interface {
+	client.Object
+
+	// The ComplianceState (Compliant/NonCompliant) of the specific policy.
+	ComplianceState() ComplianceState
+
+	// A human-readable string describing the current state of the policy, and why it is either
+	// Compliant or NonCompliant.
+	ComplianceMessage() string
+
+	// The "parent" object on this cluster for the specific policy. Generally a Policy, in the API
+	// GroupVersion `policy.open-cluster-management.io/v1`. For namespaced kinds of policies, this
+	// will usually be the owner of the policy. For cluster-scoped policies, this must be stored
+	// some other way.
+	Parent() metav1.OwnerReference
+
+	// The namespace of the "parent" object.
+	ParentNamespace() string
+}
diff --git a/pkg/compliance/k8sEventEmitter.go b/pkg/compliance/k8sEventEmitter.go
new file mode 100644
index 0000000..130aa8a
--- /dev/null
+++ b/pkg/compliance/k8sEventEmitter.go
@@ -0,0 +1,103 @@
+// Copyright Contributors to the Open Cluster Management project
+
+package compliance
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+
+	nucleusv1beta1 "open-cluster-management.io/governance-policy-nucleus/api/v1beta1"
+)
+
+// Can't be an interface because then Emit couldn't be a method
+type K8sEmitter struct {
+	Client client.Client      // required
+	Source corev1.EventSource // optional?
+
+	// debatable for inclusion; allows tweaks of the event like adding/removing labels
+	// if not included, we could skip creating the event, just build it for the user to send
+	// but if it is included, we can build bigger things on top of this, and still have extensibility
+	Mutators []func(corev1.Event) (corev1.Event, error)
+}
+
+func (e K8sEmitter) Emit(ctx context.Context, pl nucleusv1beta1.PolicyLike) (*corev1.Event, error) {
+	plGVK := pl.GetObjectKind().GroupVersionKind()
+	time := time.Now()
+
+	// This event name matches the convention of recorders from client-go
+	name := fmt.Sprintf("%v.%x", pl.Parent().Name, time.UnixNano())
+
+	// The reason must match a pattern looked for by the policy framework
+	var reason string
+	if ns := pl.GetNamespace(); ns != "" {
+		reason = "policy: " + ns + "/" + pl.GetName()
+	} else {
+		reason = "policy: " + pl.GetName()
+	}
+
+	// The message must begin with the compliance, then go into the descriptive message.
+	message := string(pl.ComplianceState()) + "; " + pl.ComplianceMessage()
+
+	evType := "Normal"
+	if pl.ComplianceState() != nucleusv1beta1.Compliant {
+		evType = "Warning"
+	}
+
+	event := corev1.Event{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "Event",
+			APIVersion: "v1",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:        name,
+			Namespace:   pl.ParentNamespace(),
+			Labels:      pl.GetLabels(),
+			Annotations: pl.GetAnnotations(),
+		},
+		InvolvedObject: corev1.ObjectReference{
+			Kind:       pl.Parent().Kind,
+			Namespace:  pl.ParentNamespace(),
+			Name:       pl.Parent().Name,
+			UID:        pl.Parent().UID,
+			APIVersion: pl.Parent().APIVersion,
+		},
+		Reason:         reason,
+		Message:        message,
+		Source:         e.Source,
+		FirstTimestamp: metav1.NewTime(time),
+		LastTimestamp:  metav1.NewTime(time),
+		Count:          1,
+		Type:           evType,
+		EventTime:      metav1.NewMicroTime(time), // does this break anything?
+		Series:         nil,
+		Action:         "ComplianceStateUpdate",
+		Related: &corev1.ObjectReference{
+			Kind:            plGVK.Kind,
+			Namespace:       pl.GetNamespace(),
+			Name:            pl.GetName(),
+			UID:             pl.GetUID(),
+			APIVersion:      plGVK.GroupVersion().String(),
+			ResourceVersion: pl.GetResourceVersion(),
+		},
+		ReportingController: e.Source.Component,
+		ReportingInstance:   e.Source.Host,
+	}
+
+	for _, mutatorFunc := range e.Mutators {
+		var err error
+
+		event, err = mutatorFunc(event)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	err := e.Client.Create(ctx, &event)
+
+	return &event, err
+}