fix: support lease obj in kubectl datadog clusteragent leader cmd (#1375

)

Co-authored-by: fanny-jiang <fanny.jiang@datadoghq.com>

.devcontainer/devcontainer.json

@@ -1,7 +1,7 @@
 {
 	"image": "mcr.microsoft.com/devcontainers/go:dev-1.22",
 	"features": {
-		"ghcr.io/devcontainers/features/docker-outside-of-docker:1": {},
+		"ghcr.io/devcontainers/features/docker-outside-of-docker:1": {}
 	},
 	"runArgs": ["--name", "datadog-operator-devenv", "-w", "/workspaces/datadog-operator"],
 	"postStartCommand": ["git", "config", "--global", "--add", "safe.directory", "/workspaces/datadog-operator"]

cmd/kubectl-datadog/clusteragent/leader/leader.go

@@ -13,9 +13,12 @@ import (
 	"github.com/DataDog/datadog-operator/pkg/plugin/common"
 
 	"github.com/spf13/cobra"
+	coordv1 "k8s.io/api/coordination/v1"
 	corev1 "k8s.io/api/core/v1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/cli-runtime/pkg/genericclioptions"
+	"k8s.io/client-go/discovery"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
@@ -29,6 +32,8 @@ type options struct {
 	genericclioptions.IOStreams
 	common.Options
 	args []string
+
+	DDAName string
 }
 
 type leaderResponse struct {
@@ -49,9 +54,9 @@ func newOptions(streams genericclioptions.IOStreams) *options {
 func New(streams genericclioptions.IOStreams) *cobra.Command {
 	o := newOptions(streams)
 	cmd := &cobra.Command{
-		Use:          "leader",
+		Use:          "leader <DatadogAgent resource name>",
 		Short:        "Get Datadog Cluster Agent leader",
-		Example:      fmt.Sprintf(leaderExample, "kubectl datadog clusteragent"),
+		Example:      fmt.Sprintf(leaderExample, "kubectl datadog clusteragent datadog-agent"),
 		SilenceUsage: true,
 		RunE: func(c *cobra.Command, args []string) error {
 			if err := o.complete(c, args); err != nil {
@@ -64,6 +69,7 @@ func New(streams genericclioptions.IOStreams) *cobra.Command {
 		},
 	}
 
+	cmd.Flags().StringVarP(&o.DDAName, "dda-name", "", "", "The DatadogAgent resource name to get the leader from")
 	o.ConfigFlags.AddFlags(cmd.Flags())
 
 	return cmd
@@ -78,34 +84,97 @@ func (o *options) complete(cmd *cobra.Command, args []string) error {
 
 // validate ensures that all required arguments and flag values are provided.
 func (o *options) validate() error {
+	if o.DDAName == "" {
+		if len(o.args) != 0 {
+			o.DDAName = o.args[0]
+		} else {
+			return fmt.Errorf("DatadogAgent resource name is required")
+		}
+	}
 	return nil
 }
 
 // run runs the leader command.
 func (o *options) run(cmd *cobra.Command) error {
-	// FIXME: Support multiple leader election config maps.
-	cmName := "datadog-leader-election"
+	leaderObjName := fmt.Sprintf("%s-leader-election", o.DDAName)
+	objKey := client.ObjectKey{Namespace: o.UserNamespace, Name: leaderObjName}
+
+	var leaderName string
+	var err error
+	var useLease bool
+
+	useLease, err = isLeaseSupported(o.DiscoveryClient)
+	if err != nil {
+		return fmt.Errorf("unable to check if lease is suppoered %w", err)
+	}
+	if useLease {
+		fmt.Fprintln(o.IOStreams.Out, "Using lease for leader election")
+		leaderName, err = o.getLeaderFromLease(objKey)
+	} else {
+		fmt.Fprintln(o.IOStreams.Out, "Using lease for configmap")
+		leaderName, err = o.getLeaderFromConfigMap(objKey)
+	}
+	if err != nil {
+		return fmt.Errorf("unable to get leader from lease: %w", err)
+	}
 
+	cmd.Println("The Pod name of the Cluster Agent is:", leaderName)
+
+	return nil
+}
+
+func (o *options) getLeaderFromLease(objKey client.ObjectKey) (string, error) {
+	lease := &coordv1.Lease{}
+	err := o.Client.Get(context.TODO(), objKey, lease)
+	if err != nil && apierrors.IsNotFound(err) {
+		return "", fmt.Errorf("lease %s/%s not found", objKey.Namespace, objKey.Name)
+	} else if err != nil {
+		return "", fmt.Errorf("unable to get leader election config map: %w", err)
+	}
+
+	// get the info from the lease
+	if lease.Spec.HolderIdentity == nil {
+		return "", fmt.Errorf("lease %s/%s does not have a holder identity", objKey.Namespace, objKey.Name)
+	}
+
+	return *lease.Spec.HolderIdentity, nil
+}
+
+func (o *options) getLeaderFromConfigMap(objKey client.ObjectKey) (string, error) {
 	// Get the config map holding the leader identity.
 	cm := &corev1.ConfigMap{}
-	err := o.Client.Get(context.TODO(), client.ObjectKey{Namespace: o.UserNamespace, Name: cmName}, cm)
+	err := o.Client.Get(context.TODO(), objKey, cm)
 	if err != nil && apierrors.IsNotFound(err) {
-		return fmt.Errorf("config map %s/%s not found", o.UserNamespace, cmName)
+		return "", fmt.Errorf("config map %s/%s not found", objKey.Namespace, objKey.Name)
 	} else if err != nil {
-		return fmt.Errorf("unable to get leader election config map: %w", err)
+		return "", fmt.Errorf("unable to get leader election config map: %w", err)
 	}
 
 	// Get leader from annotations.
 	annotations := cm.GetAnnotations()
 	leaderInfo, found := annotations["control-plane.alpha.kubernetes.io/leader"]
 	if !found {
-		return fmt.Errorf("couldn't find leader annotation on %s config map", cmName)
+		return "", fmt.Errorf("couldn't find leader annotation on %s/%s config map", objKey.Namespace, objKey.Name)
 	}
-	leader := leaderResponse{}
-	if err := json.Unmarshal([]byte(leaderInfo), &leader); err != nil {
-		return fmt.Errorf("couldn't unmarshal leader annotation: %w", err)
+	resp := leaderResponse{}
+	if err := json.Unmarshal([]byte(leaderInfo), &resp); err != nil {
+		return "", fmt.Errorf("couldn't unmarshal leader annotation: %w", err)
 	}
-	cmd.Println("The Pod name of the Cluster Agent is:", leader.HolderIdentity)
 
-	return nil
+	return resp.HolderIdentity, nil
+}
+
+func isLeaseSupported(client discovery.DiscoveryInterface) (bool, error) {
+	apiGroupList, err := client.ServerGroups()
+	if err != nil {
+		return false, fmt.Errorf("unable to discover APIGroups, err:%w", err)
+	}
+	groupVersions := metav1.ExtractGroupVersions(apiGroupList)
+	for _, grv := range groupVersions {
+		if grv == "coordination.k8s.io/v1" || grv == "coordination.k8s.io/v1beta1" {
+			return true, nil
+		}
+	}
+
+	return false, nil
 }

pkg/plugin/common/options.go

@@ -11,17 +11,19 @@ import (
 	"github.com/spf13/cobra"
 	apiextensionclient "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
 	"k8s.io/cli-runtime/pkg/genericclioptions"
+	"k8s.io/client-go/discovery"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/clientcmd"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
 // Options encapsulates the common fields of command options
 type Options struct {
-	ConfigFlags  *genericclioptions.ConfigFlags
-	Client       client.Client
-	Clientset    *kubernetes.Clientset
-	APIExtClient *apiextensionclient.Clientset
+	ConfigFlags     *genericclioptions.ConfigFlags
+	Client          client.Client
+	Clientset       *kubernetes.Clientset
+	APIExtClient    *apiextensionclient.Clientset
+	DiscoveryClient discovery.DiscoveryInterface
 
 	UserNamespace string
 }
@@ -52,6 +54,12 @@ func (o *Options) Init(cmd *cobra.Command) error {
 	}
 	o.SetApiExtensionClient(apiextClient)
 
+	discoveryClient, err := discovery.NewDiscoveryClientForConfig(restConfig)
+	if err != nil {
+		return fmt.Errorf("unable to create DiscoveryClient, err:%w", err)
+	}
+	o.SetDiscoveryClient(discoveryClient)
+
 	nsConfig, _, err := clientConfig.Namespace()
 	if err != nil {
 		return err
@@ -90,6 +98,11 @@ func (o *Options) SetApiExtensionClient(client *apiextensionclient.Clientset) {
 	o.APIExtClient = client
 }
 
+// SetDiscoveryClient configures the DiscoveryClient
+func (o *Options) SetDiscoveryClient(client discovery.DiscoveryInterface) {
+	o.DiscoveryClient = client
+}
+
 // GetClientConfig returns the client config
 func (o *Options) GetClientConfig() clientcmd.ClientConfig {
 	return o.ConfigFlags.ToRawKubeConfigLoader()