Delete a Workload if the related object is absent (#779)

Workload object counts were previously getting out of control as the recreation of a related Pod would spawn a new workload, while the old one would never get deleted (except for StatefulSets, where the names of Pods are stable). Workloads without a matching object are now deleted.

cmd/cozystack-controller/main.go

@@ -178,6 +178,15 @@ func main() {
 		setupLog.Error(err, "unable to create controller", "controller", "WorkloadMonitor")
 		os.Exit(1)
 	}
+
+	if err = (&controller.WorkloadReconciler{
+		Client: mgr.GetClient(),
+		Scheme: mgr.GetScheme(),
+	}).SetupWithManager(mgr); err != nil {
+		setupLog.Error(err, "unable to create controller", "controller", "Workload")
+		os.Exit(1)
+	}
+
 	// +kubebuilder:scaffold:builder
 
 	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {

internal/controller/workload_controller.go

@@ -0,0 +1,87 @@
+package controller
+
+import (
+	"context"
+	"strings"
+
+	corev1 "k8s.io/api/core/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+
+	cozyv1alpha1 "github.com/cozystack/cozystack/api/v1alpha1"
+)
+
+// WorkloadMonitorReconciler reconciles a WorkloadMonitor object
+type WorkloadReconciler struct {
+	client.Client
+	Scheme *runtime.Scheme
+}
+
+func (r *WorkloadReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
+	logger := log.FromContext(ctx)
+	w := &cozyv1alpha1.Workload{}
+	err := r.Get(ctx, req.NamespacedName, w)
+	if err != nil {
+		if apierrors.IsNotFound(err) {
+			return ctrl.Result{}, nil
+		}
+		logger.Error(err, "Unable to fetch Workload")
+		return ctrl.Result{}, err
+	}
+
+	// it's being deleted, nothing to handle
+	if w.DeletionTimestamp != nil {
+		return ctrl.Result{}, nil
+	}
+
+	t := getMonitoredObject(w)
+	err = r.Get(ctx, types.NamespacedName{Name: t.GetName(), Namespace: t.GetNamespace()}, t)
+
+	// found object, nothing to do
+	if err == nil {
+		return ctrl.Result{}, nil
+	}
+
+	// error getting object but not 404 -- requeue
+	if !apierrors.IsNotFound(err) {
+		logger.Error(err, "failed to get dependent object", "kind", t.GetObjectKind(), "dependent-object-name", t.GetName())
+		return ctrl.Result{}, err
+	}
+
+	err = r.Delete(ctx, w)
+	if err != nil {
+		logger.Error(err, "failed to delete workload")
+	}
+	return ctrl.Result{}, err
+}
+
+// SetupWithManager registers our controller with the Manager and sets up watches.
+func (r *WorkloadReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	return ctrl.NewControllerManagedBy(mgr).
+		// Watch WorkloadMonitor objects
+		For(&cozyv1alpha1.Workload{}).
+		Complete(r)
+}
+
+func getMonitoredObject(w *cozyv1alpha1.Workload) client.Object {
+	if strings.HasPrefix(w.Name, "pvc-") {
+		obj := &corev1.PersistentVolumeClaim{}
+		obj.Name = strings.TrimPrefix(w.Name, "pvc-")
+		obj.Namespace = w.Namespace
+		return obj
+	}
+	if strings.HasPrefix(w.Name, "svc-") {
+		obj := &corev1.Service{}
+		obj.Name = strings.TrimPrefix(w.Name, "svc-")
+		obj.Namespace = w.Namespace
+		return obj
+	}
+	obj := &corev1.Pod{}
+	obj.Name = w.Name
+	obj.Namespace = w.Namespace
+	return obj
+}