feat: Support APIService relationships

Signed-off-by: Justin Toh <tohjustin@hotmail.com>

README.md

@@ -86,6 +86,7 @@ monitoring-system   └── ServiceAccount/kube-state-metrics
 List of supported relationships used for discovering dependent objects:
 
 - Kubernetes
+  - [APIService References](https://kubernetes.io/docs/reference/kubernetes-api/cluster-resources/api-service-v1/)
   - [ClusterRole References](https://kubernetes.io/docs/reference/kubernetes-api/authorization-resources/cluster-role-v1/), [ClusterRoleBinding References](https://kubernetes.io/docs/reference/kubernetes-api/authorization-resources/cluster-role-binding-v1/), [Role References](https://kubernetes.io/docs/reference/kubernetes-api/authorization-resources/role-v1/) & [RoleBinding References](https://kubernetes.io/docs/reference/kubernetes-api/authorization-resources/role-binding-v1/)
   - [Controller References](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/api-machinery/controller-ref.md) & [Owner References](https://kubernetes.io/docs/concepts/overview/working-with-objects/owners-dependents/)
   - [CSINode References](https://kubernetes.io/docs/reference/kubernetes-api/config-and-storage-resources/csi-node-v1/)

go.mod

@@ -12,5 +12,6 @@ require (
 	k8s.io/cli-runtime v0.22.1
 	k8s.io/client-go v0.22.1
 	k8s.io/klog/v2 v2.9.0
+	k8s.io/kube-aggregator v0.22.1
 	k8s.io/kubectl v0.22.1
 )

go.sum

@@ -1469,6 +1469,8 @@ k8s.io/klog/v2 v2.2.0/go.mod h1:Od+F08eJP+W3HUb4pSrPpgp9DGU4GzlpG/TmITuYh/Y=
 k8s.io/klog/v2 v2.4.0/go.mod h1:Od+F08eJP+W3HUb4pSrPpgp9DGU4GzlpG/TmITuYh/Y=
 k8s.io/klog/v2 v2.9.0 h1:D7HV+n1V57XeZ0m6tdRkfknthUaM06VFbWldOFh8kzM=
 k8s.io/klog/v2 v2.9.0/go.mod h1:hy9LJ/NvuK+iVyP4Ehqva4HxZG/oXyIS3n3Jmire4Ec=
+k8s.io/kube-aggregator v0.22.1 h1:hsntyWsnkLiL4ccmoKfqiUVyxnlnqtqPRMuq/mT2wGQ=
+k8s.io/kube-aggregator v0.22.1/go.mod h1:VbmI+8fUeCPkzSvarWTrlIGEgUGEGI/66SFajDQ0Pdc=
 k8s.io/kube-openapi v0.0.0-20201113171705-d219536bb9fd/go.mod h1:WOJ3KddDSol4tAGcJo0Tvi+dK12EcqSLqcWsryKMpfM=
 k8s.io/kube-openapi v0.0.0-20210421082810-95288971da7e h1:KLHHjkdQFomZy8+06csTWZ0m1343QqxZhR2LJ1OxCYM=
 k8s.io/kube-openapi v0.0.0-20210421082810-95288971da7e/go.mod h1:vHXdDvt9+2spS2Rx9ql3I8tycm3H9FDfdUoIuKCefvw=

internal/graph/graph.go

@@ -486,6 +486,13 @@ func ResolveDependents(m meta.RESTMapper, objects []unstructuredv1.Unstructured,
 				klog.V(4).Infof("Failed to get relationships for validatingwebhookconfiguration named \"%s\": %s", node.Name, err)
 				continue
 			}
+		// Populate dependents based on APIService relationships
+		case node.Group == "apiregistration.k8s.io" && node.Kind == "APIService":
+			rmap, err = getAPIServiceRelationships(node)
+			if err != nil {
+				klog.V(4).Infof("Failed to get relationships for apiservice named \"%s\": %s", node.Name, err)
+				continue
+			}
 		// Populate dependents based on Event relationships
 		case (node.Group == "events.k8s.io" || node.Group == "") && node.Kind == "Event":
 			rmap, err = getEventRelationships(node)

internal/graph/kubernetes.go

@@ -17,9 +17,13 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/sets"
+	apiregistrationv1 "k8s.io/kube-aggregator/pkg/apis/apiregistration/v1"
 )
 
 const (
+	// Kubernetes APIService relationships.
+	RelationshipAPIService Relationship = "APIService"
+
 	// Kubernetes ClusterRole, ClusterRoleBinding, RoleBinding relationships.
 	RelationshipClusterRoleAggregationRule Relationship = "ClusterRoleAggregationRule"
 	RelationshipClusterRolePolicyRule      Relationship = "ClusterRolePolicyRule"
@@ -99,6 +103,29 @@ const (
 	RelationshipVolumeAttachmentSourceVolumeStorageClass    Relationship = "VolumeAttachmentSourceVolumeStorageClass"
 )
 
+// getAPIServiceRelationships returns a map of relationships that this
+// APIService has with other objects, based on what was referenced in its
+// manifest.
+func getAPIServiceRelationships(n *Node) (*RelationshipMap, error) {
+	var apisvc apiregistrationv1.APIService
+	err := runtime.DefaultUnstructuredConverter.FromUnstructured(n.UnstructuredContent(), &apisvc)
+	if err != nil {
+		return nil, err
+	}
+
+	// var os ObjectSelector
+	var ref ObjectReference
+	result := newRelationshipMap()
+
+	// RelationshipAPIService
+	if svc := apisvc.Spec.Service; svc != nil {
+		ref = ObjectReference{Kind: "Service", Namespace: svc.Namespace, Name: svc.Name}
+		result.AddDependencyByKey(ref.Key(), RelationshipAPIService)
+	}
+
+	return &result, nil
+}
+
 // getClusterRoleRelationships returns a map of relationships that this
 // ClusterRole has with other objects, based on what was referenced in
 // its manifest.
@@ -109,8 +136,8 @@ func getClusterRoleRelationships(n *Node) (*RelationshipMap, error) {
 		return nil, err
 	}
 
-	var ols ObjectLabelSelector
 	var os ObjectSelector
+	var ols ObjectLabelSelector
 	var ref ObjectReference
 	result := newRelationshipMap()
 
@@ -645,8 +672,8 @@ func getRoleRelationships(n *Node) (*RelationshipMap, error) {
 	if err != nil {
 		return nil, err
 	}
-
 	var os ObjectSelector
+
 	var ref ObjectReference
 	result := newRelationshipMap()
 

internal/printers/printers_humanreadable.go

@@ -18,6 +18,7 @@ import (
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/duration"
 	"k8s.io/client-go/util/jsonpath"
+	apiregistrationv1 "k8s.io/kube-aggregator/pkg/apis/apiregistration/v1"
 
 	"github.com/tohjustin/kube-lineage/internal/graph"
 )
@@ -160,6 +161,28 @@ func getObjectReadyStatus(u *unstructuredv1.Unstructured) (string, string, error
 	return ready, status, nil
 }
 
+// getAPIServiceReadyStatus returns the ready & status value of a APIService
+// which is based off the table cell values computed by printAPIService from
+// https://github.com/kubernetes/kubernetes/blob/v1.22.1/pkg/printers/internalversion/printers.go.
+func getAPIServiceReadyStatus(u *unstructuredv1.Unstructured) (string, string, error) {
+	var apisvc apiregistrationv1.APIService
+	err := runtime.DefaultUnstructuredConverter.FromUnstructured(u.UnstructuredContent(), &apisvc)
+	if err != nil {
+		return "", "", err
+	}
+	var ready, status string
+	for _, condition := range apisvc.Status.Conditions {
+		if condition.Type == apiregistrationv1.Available {
+			ready = string(condition.Status)
+			if condition.Status != apiregistrationv1.ConditionTrue {
+				status = condition.Reason
+			}
+		}
+	}
+
+	return ready, status, nil
+}
+
 // getDaemonSetReadyStatus returns the ready & status value of a DaemonSet
 // which is based off the table cell values computed by printDaemonSet from
 // https://github.com/kubernetes/kubernetes/blob/v1.22.1/pkg/printers/internalversion/printers.go.
@@ -413,7 +436,7 @@ func getVolumeAttachmentReadyStatus(u *unstructuredv1.Unstructured) (string, str
 }
 
 // nodeToTableRow converts the provided node into a table row.
-//nolint:gocognit,goconst
+//nolint:funlen,gocognit,goconst
 func nodeToTableRow(node *graph.Node, rset graph.RelationshipSet, namePrefix string, showGroupFn func(kind string) bool) metav1.TableRow {
 	var name, ready, status, age string
 	var relationships interface{}
@@ -443,6 +466,8 @@ func nodeToTableRow(node *graph.Node, rset graph.RelationshipSet, namePrefix str
 		ready, status, _ = getStatefulSetReadyStatus(node.Unstructured)
 	case node.Group == "policy" && node.Kind == "PodDisruptionBudget":
 		ready, status, _ = getPodDisruptionBudgetReadyStatus(node.Unstructured)
+	case node.Group == "apiregistration.k8s.io" && node.Kind == "APIService":
+		ready, status, _ = getAPIServiceReadyStatus(node.Unstructured)
 	case node.Group == "events.k8s.io" && node.Kind == "Event":
 		ready, status, _ = getEventReadyStatus(node.Unstructured)
 	case node.Group == "storage.k8s.io" && node.Kind == "VolumeAttachment":