feat: Introduce CloudEvents to KEDA (#4968)

Co-authored-by: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es>
Co-authored-by: Zbynek Roubalik <zroubalik@gmail.com>
Co-authored-by: Josef Karasek <karasek.jose@gmail.com>
Co-authored-by: Jan Wozniak <wozniak.jan@gmail.com>

CHANGELOG.md

@@ -56,7 +56,7 @@ To learn more about active deprecations, we recommend checking [GitHub Discussio
 
 Here is an overview of all new **experimental** features:
 
-- **General**: TODO ([#XXX](https://github.com/kedacore/keda/issues/XXX))
+- **General**:  Emit CloudEvents on major KEDA events ([#3533](https://github.com/kedacore/keda/issues/3533))
 
 ### Improvements
 

Makefile

@@ -160,14 +160,16 @@ proto-gen: protoc-gen ## Generate Liiklus, ExternalScaler and MetricsService pro
 	PATH="$(LOCALBIN):$(PATH)" protoc -I vendor --proto_path=pkg/metricsservice/api metrics.proto --go_out=pkg/metricsservice/api --go-grpc_out=pkg/metricsservice/api
 
 .PHONY: mockgen-gen
-mockgen-gen: mockgen pkg/mock/mock_scaling/mock_interface.go pkg/mock/mock_scaling/mock_executor/mock_interface.go pkg/mock/mock_scaler/mock_scaler.go pkg/mock/mock_scale/mock_interfaces.go pkg/mock/mock_client/mock_interfaces.go pkg/scalers/liiklus/mocks/mock_liiklus.go pkg/mock/mock_secretlister/mock_interfaces.go
+mockgen-gen: mockgen pkg/mock/mock_scaling/mock_interface.go pkg/mock/mock_scaling/mock_executor/mock_interface.go pkg/mock/mock_scaler/mock_scaler.go pkg/mock/mock_scale/mock_interfaces.go pkg/mock/mock_client/mock_interfaces.go pkg/scalers/liiklus/mocks/mock_liiklus.go pkg/mock/mock_secretlister/mock_interfaces.go pkg/mock/mock_eventemitter/mock_interface.go
 
 pkg/mock/mock_scaling/mock_interface.go: pkg/scaling/scale_handler.go
 	$(MOCKGEN) -destination=$@ -package=mock_scaling -source=$^
 pkg/mock/mock_scaling/mock_executor/mock_interface.go: pkg/scaling/executor/scale_executor.go
 	$(MOCKGEN) -destination=$@ -package=mock_executor -source=$^
 pkg/mock/mock_scaler/mock_scaler.go: pkg/scalers/scaler.go
 	$(MOCKGEN) -destination=$@ -package=mock_scalers -source=$^
+pkg/mock/mock_eventemitter/mock_interface.go: pkg/eventemitter/eventemitter.go
+	$(MOCKGEN) -destination=$@ -package=mock_eventemitter -source=$^
 pkg/mock/mock_secretlister/mock_interfaces.go: vendor/k8s.io/client-go/listers/core/v1/secret.go
 	mkdir -p pkg/mock/mock_secretlister
 	$(MOCKGEN) k8s.io/client-go/listers/core/v1 SecretLister,SecretNamespaceLister > $@

apis/eventing/v1alpha1/cloudeventsource_types.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2023 The KEDA 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 v1alpha1
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	v1alpha1 "github.com/kedacore/keda/v2/apis/keda/v1alpha1"
+)
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+
+// CloudEventSource defines how a KEDA event will be sent to event sink
+// +kubebuilder:resource:path=cloudeventsources,scope=Namespaced
+// +kubebuilder:subresource:status
+// +kubebuilder:printcolumn:name="Active",type="string",JSONPath=".status.conditions[?(@.type==\"Active\")].status"
+type CloudEventSource struct {
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata,omitempty"`
+
+	Spec   CloudEventSourceSpec   `json:"spec"`
+	Status CloudEventSourceStatus `json:"status,omitempty"`
+}
+
+// +kubebuilder:object:root=true
+
+// CloudEventSourceList is a list of CloudEventSource resources
+type CloudEventSourceList struct {
+	metav1.TypeMeta `json:",inline"`
+	metav1.ListMeta `json:"metadata"`
+	Items           []CloudEventSource `json:"items"`
+}
+
+// CloudEventSourceSpec defines the spec of CloudEventSource
+type CloudEventSourceSpec struct {
+	// +optional
+	ClusterName string `json:"clusterName,omitempty"`
+
+	Destination Destination `json:"destination"`
+}
+
+// CloudEventSourceStatus defines the observed state of CloudEventSource
+// +optional
+type CloudEventSourceStatus struct {
+	// +optional
+	Conditions v1alpha1.Conditions `json:"conditions,omitempty"`
+}
+
+// Destination defines the various ways to emit events
+type Destination struct {
+	// +optional
+	HTTP *CloudEventHTTP `json:"http"`
+}
+
+type CloudEventHTTP struct {
+	URI string `json:"uri"`
+}
+
+func init() {
+	SchemeBuilder.Register(&CloudEventSource{}, &CloudEventSourceList{})
+}
+
+// GenerateIdentifier returns identifier for the object in for "kind.namespace.name"
+func (t *CloudEventSource) GenerateIdentifier() string {
+	return v1alpha1.GenerateIdentifier("CloudEventSource", t.Namespace, t.Name)
+}
+
+// GetCloudEventSourceInitializedConditions returns CloudEventSource Conditions initialized to the default -> Status: Unknown
+func GetCloudEventSourceInitializedConditions() *v1alpha1.Conditions {
+	return &v1alpha1.Conditions{{Type: v1alpha1.ConditionActive, Status: metav1.ConditionUnknown}}
+}

apis/eventing/v1alpha1/condition_types.go

@@ -0,0 +1,28 @@
+/*
+Copyright 2023 The KEDA 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 v1alpha1
+
+const (
+	// CloudEventSourceConditionActiveReason defines the active condition reason for CloudEventSource
+	CloudEventSourceConditionActiveReason = "CloudEventSourceActive"
+	// CloudEventSourceConditionFailedReason defines the failed condition reason for CloudEventSource
+	CloudEventSourceConditionFailedReason = "CloudEventSourceFailed"
+	// CloudEventSourceConditionActiveMessage defines the active condition message for CloudEventSource
+	CloudEventSourceConditionActiveMessage = "Is configured to send events to the configured destination"
+	// CloudEventSourceConditionFailedMessage defines the failed condition message for CloudEventSource
+	CloudEventSourceConditionFailedMessage = "Failed to send events to the configured destination"
+)

apis/eventing/v1alpha1/groupversion_info.go

@@ -0,0 +1,36 @@
+/*
+Copyright 2023 The KEDA 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 v1alpha1 contains API Schema definitions for the eventing v1alpha1 API group
+// +kubebuilder:object:generate=true
+// +groupName=eventing.keda.sh
+package v1alpha1
+
+import (
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/controller-runtime/pkg/scheme"
+)
+
+var (
+	// GroupVersion is group version used to register these objects
+	GroupVersion = schema.GroupVersion{Group: "eventing.keda.sh", Version: "v1alpha1"}
+
+	// SchemeBuilder is used to add go types to the GroupVersionKind scheme
+	SchemeBuilder = &scheme.Builder{GroupVersion: GroupVersion}
+
+	// AddToScheme adds the types in this group-version to the given scheme.
+	AddToScheme = SchemeBuilder.AddToScheme
+)

apis/keda/v1alpha1/condition_types.go

@@ -37,8 +37,8 @@ const (
 )
 
 const (
-	// ScaledObjectConditionReadySucccesReason defines the default Reason for correct ScaledObject
-	ScaledObjectConditionReadySucccesReason = "ScaledObjectReady"
+	// ScaledObjectConditionReadySuccessReason defines the default Reason for correct ScaledObject
+	ScaledObjectConditionReadySuccessReason = "ScaledObjectReady"
 	// ScaledObjectConditionReadySuccessMessage defines the default Message for correct ScaledObject
 	ScaledObjectConditionReadySuccessMessage = "ScaledObject is defined correctly and is ready for scaling"
 	// ScaledObjectConditionPausedReason defines the default Reason for paused ScaledObject