Add ObservedObjectCollection API type (#217)

* Add `ObservedObjectCollection` API type

Objects in the collection are defined by:
* GVK
* optional namespace
* label selector

The objects are fetched using the specified provider config
and for the matched objects the provider creates counterpart
observe-only objects in the local cluster.

The created objects are owned by the collection resource and
reconciled as usual by the provider. They are labeled with a common label, so that they can be fetched easily. 
The label is discoverable by reading  `.status.membershipLabel` field of `ObservedObjectCollection`.

Signed-off-by: Predrag Knezevic <[email protected]>

apis/kubernetes.go

@@ -22,6 +22,7 @@ import (
 
 	objectv1alpha1 "github.com/crossplane-contrib/provider-kubernetes/apis/object/v1alpha1"
 	objectv1alhpa2 "github.com/crossplane-contrib/provider-kubernetes/apis/object/v1alpha2"
+	observedobjectcollectionv1alpha1 "github.com/crossplane-contrib/provider-kubernetes/apis/observedobjectcollection/v1alpha1"
 	templatev1alpha1 "github.com/crossplane-contrib/provider-kubernetes/apis/v1alpha1"
 )
 
@@ -31,6 +32,7 @@ func init() {
 		templatev1alpha1.SchemeBuilder.AddToScheme,
 		objectv1alpha1.SchemeBuilder.AddToScheme,
 		objectv1alhpa2.SchemeBuilder.AddToScheme,
+		observedobjectcollectionv1alpha1.SchemeBuilder.AddToScheme,
 	)
 }
 

apis/observedobjectcollection/v1alpha1/doc.go

@@ -0,0 +1,22 @@
+/*
+Copyright 2024 The Crossplane 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 the v1alpha1 group ObservedObjectCollection resources of the Kubernetes provider.
+// +kubebuilder:ac:generate=true
+// +kubebuilder:object:generate=true
+// +groupName=kubernetes.crossplane.io
+// +versionName=v1alpha1
+package v1alpha1

apis/observedobjectcollection/v1alpha1/register.go

@@ -0,0 +1,50 @@
+/*
+Copyright 2024 The Crossplane 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 (
+	"reflect"
+
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/controller-runtime/pkg/scheme"
+)
+
+// Package type metadata.
+const (
+	Group   = "kubernetes.crossplane.io"
+	Version = "v1alpha1"
+)
+
+var (
+	// SchemeGroupVersion is group version used to register these objects
+	SchemeGroupVersion = schema.GroupVersion{Group: Group, Version: Version}
+
+	// SchemeBuilder is used to add go types to the GroupVersionKind scheme
+	SchemeBuilder = &scheme.Builder{GroupVersion: SchemeGroupVersion}
+)
+
+// ProviderConfig type metadata.
+var (
+	ObservedObjectCollectionKind             = reflect.TypeOf(ObservedObjectCollection{}).Name()
+	ObservedObjectCollectionGroupKind        = schema.GroupKind{Group: Group, Kind: ObservedObjectCollectionKind}.String()
+	ObservedObjectCollectionAPIVersion       = ObservedObjectCollectionKind + "." + SchemeGroupVersion.String()
+	ObservedObjectCollectionGroupVersionKind = SchemeGroupVersion.WithKind(ObservedObjectCollectionKind)
+)
+
+func init() {
+	SchemeBuilder.Register(&ObservedObjectCollection{}, &ObservedObjectCollectionList{})
+}

apis/observedobjectcollection/v1alpha1/types.go

@@ -0,0 +1,126 @@
+/*
+Copyright 2024 The Crossplane 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 (
+	"k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	v12 "github.com/crossplane/crossplane-runtime/apis/common/v1"
+)
+
+// +kubebuilder:object:root=true
+
+// A ObservedObjectCollection is a provider Kubernetes API type
+// +kubebuilder:subresource:status
+// +kubebuilder:printcolumn:name="KIND",type="string",JSONPath=".spec.kind"
+// +kubebuilder:printcolumn:name="APIVERSION",type="string",JSONPath=".spec.apiVersion",priority=1
+// +kubebuilder:printcolumn:name="PROVIDERCONFIG",type="string",JSONPath=".spec.providerConfigRef.name"
+// +kubebuilder:printcolumn:name="SYNCED",type="string",JSONPath=".status.conditions[?(@.type=='Synced')].status"
+// +kubebuilder:printcolumn:name="READY",type="string",JSONPath=".status.conditions[?(@.type=='Ready')].status"
+// +kubebuilder:printcolumn:name="AGE",type="date",JSONPath=".metadata.creationTimestamp"
+// +kubebuilder:resource:scope=Cluster,categories={crossplane,managed,kubernetes}
+// +kubebuilder:validation:XValidation:rule="size(self.metadata.name) < 64",message="metadata.name max length is 63"
+type ObservedObjectCollection struct {
+	v1.TypeMeta   `json:",inline"`
+	v1.ObjectMeta `json:"metadata,omitempty"`
+	Spec          ObservedObjectCollectionSpec   `json:"spec"`
+	Status        ObservedObjectCollectionStatus `json:"status,omitempty"`
+}
+
+// +kubebuilder:object:root=true
+
+// ObservedObjectCollectionList contains a list of ObservedObjectCollection
+type ObservedObjectCollectionList struct {
+	v1.TypeMeta `json:",inline"`
+	v1.ListMeta `json:"metadata,omitempty"`
+	Items       []ObservedObjectCollection `json:"items"`
+}
+
+// ObservedObjectCollectionSpec defines the desired state of ObservedObjectCollection
+type ObservedObjectCollectionSpec struct {
+
+	// ObserveObjects declares what criteria object need to fulfil
+	// to become a member of this collection
+	ObserveObjects ObserveObjectCriteria `json:"observeObjects"`
+
+	// ProviderConfigReference specifies how the provider that will be used to
+	// create, observe, update, and delete this managed resource should be
+	// configured.
+	// +kubebuilder:default={"name": "default"}
+	ProviderConfigReference v12.Reference `json:"providerConfigRef,omitempty"`
+
+	// Template when defined is used for creating Object instances
+	// +optional
+	Template *ObservedObjectTemplate `json:"objectTemplate,omitempty"`
+}
+
+// ObserveObjectCriteria declares criteria for an object to be a part of collection
+type ObserveObjectCriteria struct {
+
+	// APIVersion of objects that should be matched by the selector
+	// +kubebuilder:validation:MinLength:=1
+	APIVersion string `json:"apiVersion"`
+
+	// Kind of objects that should be matched by the selector
+	// +kubebuilder:validation:MinLength:=1
+	Kind string `json:"kind"`
+
+	// Namespace where to look for objects.
+	// If omitted, search is performed across all namespaces.
+	// For cluster-scoped objects, omit it.
+	// +optional
+	Namespace string `json:"namespace,omitempty"`
+
+	// Selector defines the criteria for including objects into the collection
+	Selector v1.LabelSelector `json:"selector"`
+}
+
+// ObservedObjectTemplate represents template used when creating observe-only Objects matching the given selector
+type ObservedObjectTemplate struct {
+
+	// Objects metadata
+	Metadata ObservedObjectTemplateMetadata `json:"metadata,omitempty"`
+}
+
+// ObservedObjectTemplateMetadata represents objects metadata
+type ObservedObjectTemplateMetadata struct {
+
+	// Labels of an object
+	Labels map[string]string `json:"labels,omitempty"`
+
+	// Annotations of an object
+	Annotations map[string]string `json:"annotations,omitempty"`
+}
+
+// ObservedObjectCollectionStatus represents the observed state of a ObservedObjectCollection
+type ObservedObjectCollectionStatus struct {
+	v12.ResourceStatus `json:",inline"`
+
+	// MembershipLabel is the label set on each member of this collection
+	// and can be used for fetching them.
+	// +optional
+	MembershipLabel map[string]string `json:"membershipLabel,omitempty"`
+}
+
+// ObservedObjectReference represents a reference to Object with ObserveOnly management policy
+type ObservedObjectReference struct {
+
+	// Name of the observed object
+	// +kubebuilder:validation:MinLength:=1
+	// +kubebuilder:validation:MaxLength:=253
+	Name string `json:"name"`
+}