[cozystack-controller] Introduce system helm reconciler (#1033)

Signed-off-by: Andrei Kvapil <kvapss@gmail.com>


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Introduced automated monitoring of key configuration changes to ensure
system applications are promptly updated when relevant settings are
modified.
- **Bug Fixes**
- Improved error logging for controller setup to display accurate
controller names and ensure consistent error handling.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

cmd/cozystack-controller/main.go

@@ -194,7 +194,15 @@ func main() {
 		Client: mgr.GetClient(),
 		Scheme: mgr.GetScheme(),
 	}).SetupWithManager(mgr); err != nil {
-		setupLog.Error(err, "unable to create controller", "controller", "Workload")
+		setupLog.Error(err, "unable to create controller", "controller", "TenantHelmReconciler")
+		os.Exit(1)
+	}
+
+	if err = (&controller.CozystackConfigReconciler{
+		Client: mgr.GetClient(),
+		Scheme: mgr.GetScheme(),
+	}).SetupWithManager(mgr); err != nil {
+		setupLog.Error(err, "unable to create controller", "controller", "CozystackConfigReconciler")
 		os.Exit(1)
 	}
 

internal/controller/system_helm_reconciler.go

@@ -0,0 +1,139 @@
+package controller
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"sort"
+	"time"
+
+	helmv2 "github.com/fluxcd/helm-controller/api/v2"
+	corev1 "k8s.io/api/core/v1"
+	kerrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/runtime"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/event"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/predicate"
+)
+
+type CozystackConfigReconciler struct {
+	client.Client
+	Scheme *runtime.Scheme
+}
+
+var configMapNames = []string{"cozystack", "cozystack-branding", "cozystack-scheduling"}
+
+const configMapNamespace = "cozy-system"
+const digestAnnotation = "cozystack.io/cozy-config-digest"
+const forceReconcileKey = "reconcile.fluxcd.io/forceAt"
+const requestedAt = "reconcile.fluxcd.io/requestedAt"
+
+func (r *CozystackConfigReconciler) Reconcile(ctx context.Context, _ ctrl.Request) (ctrl.Result, error) {
+	log := log.FromContext(ctx)
+
+	digest, err := r.computeDigest(ctx)
+	if err != nil {
+		log.Error(err, "failed to compute config digest")
+		return ctrl.Result{}, nil
+	}
+
+	var helmList helmv2.HelmReleaseList
+	if err := r.List(ctx, &helmList); err != nil {
+		return ctrl.Result{}, fmt.Errorf("failed to list HelmReleases: %w", err)
+	}
+
+	now := time.Now().Format(time.RFC3339Nano)
+	updated := 0
+
+	for _, hr := range helmList.Items {
+		isSystemApp := hr.Labels["cozystack.io/system-app"] == "true"
+		isTenantRoot := hr.Namespace == "tenant-root" && hr.Name == "tenant-root"
+		if !isSystemApp && !isTenantRoot {
+			continue
+		}
+
+		if hr.Annotations == nil {
+			hr.Annotations = map[string]string{}
+		}
+
+		if hr.Annotations[digestAnnotation] == digest {
+			continue
+		}
+
+		patch := client.MergeFrom(hr.DeepCopy())
+		hr.Annotations[digestAnnotation] = digest
+		hr.Annotations[forceReconcileKey] = now
+		hr.Annotations[requestedAt] = now
+
+		if err := r.Patch(ctx, &hr, patch); err != nil {
+			log.Error(err, "failed to patch HelmRelease", "name", hr.Name, "namespace", hr.Namespace)
+			continue
+		}
+		updated++
+		log.Info("patched HelmRelease with new config digest", "name", hr.Name, "namespace", hr.Namespace)
+	}
+
+	log.Info("finished reconciliation", "updatedHelmReleases", updated)
+	return ctrl.Result{}, nil
+}
+
+func (r *CozystackConfigReconciler) computeDigest(ctx context.Context) (string, error) {
+	hash := sha256.New()
+
+	for _, name := range configMapNames {
+		var cm corev1.ConfigMap
+		err := r.Get(ctx, client.ObjectKey{Namespace: configMapNamespace, Name: name}, &cm)
+		if err != nil {
+			if kerrors.IsNotFound(err) {
+				continue // ignore missing
+			}
+			return "", err
+		}
+
+		// Sort keys for consistent hashing
+		var keys []string
+		for k := range cm.Data {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+
+		for _, k := range keys {
+			v := cm.Data[k]
+			fmt.Fprintf(hash, "%s:%s=%s\n", name, k, v)
+		}
+	}
+
+	return hex.EncodeToString(hash.Sum(nil)), nil
+}
+
+func (r *CozystackConfigReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	return ctrl.NewControllerManagedBy(mgr).
+		WithEventFilter(predicate.Funcs{
+			UpdateFunc: func(e event.UpdateEvent) bool {
+				cm, ok := e.ObjectNew.(*corev1.ConfigMap)
+				return ok && cm.Namespace == configMapNamespace && contains(configMapNames, cm.Name)
+			},
+			CreateFunc: func(e event.CreateEvent) bool {
+				cm, ok := e.Object.(*corev1.ConfigMap)
+				return ok && cm.Namespace == configMapNamespace && contains(configMapNames, cm.Name)
+			},
+			DeleteFunc: func(e event.DeleteEvent) bool {
+				cm, ok := e.Object.(*corev1.ConfigMap)
+				return ok && cm.Namespace == configMapNamespace && contains(configMapNames, cm.Name)
+			},
+		}).
+		For(&corev1.ConfigMap{}).
+		Complete(r)
+}
+
+func contains(slice []string, val string) bool {
+	for _, s := range slice {
+		if s == val {
+			return true
+		}
+	}
+	return false
+}