initial commit

internal/controller/resolution_controller.go

@@ -0,0 +1,146 @@
+/*
+Copyright 2026.
+
+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 controller
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"net"
+	"slices"
+
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/runtime"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	logf "sigs.k8s.io/controller-runtime/pkg/log"
+
+	dnsv1 "stinnesbeck.com/dns/api/v1"
+)
+
+// ResolutionReconciler reconciles a Resolution object
+type ResolutionReconciler struct {
+	client.Client
+	Scheme *runtime.Scheme
+}
+
+// +kubebuilder:rbac:groups=dns.stinnesbeck.com,resources=resolutions,verbs=get;list;watch;create;update;patch;delete
+// +kubebuilder:rbac:groups=dns.stinnesbeck.com,resources=resolutions/status,verbs=get;update;patch
+// +kubebuilder:rbac:groups=dns.stinnesbeck.com,resources=resolutions/finalizers,verbs=update
+
+// Reconcile is part of the main kubernetes reconciliation loop which aims to
+// move the current state of the cluster closer to the desired state.
+// TODO(user): Modify the Reconcile function to compare the state specified by
+// the Resolution object against the actual cluster state, and then
+// perform operations to make the cluster state reflect the state specified by
+// the user.
+//
+// For more details, check Reconcile and its Result here:
+// - https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.23.3/pkg/reconcile
+func (r *ResolutionReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
+	log := logf.FromContext(ctx)
+
+	var resolution dnsv1.Resolution
+
+	switch err := r.Get(ctx, req.NamespacedName, &resolution); {
+	case apierrors.IsNotFound(err):
+		// resolution was deleted, this is expected
+		// exit reconcile loop here
+		return ctrl.Result{}, nil
+
+	case err != nil:
+		// an error occurred this is not expected
+		log.Error(err, "error while retrieving resolution")
+		return ctrl.Result{}, err
+	}
+
+	// Snapshot before mutation
+	patchBase := resolution.DeepCopy()
+
+	addrs, err := net.LookupHost(resolution.Spec.Address)
+	if err != nil {
+		log.Error(err, "error while resolving resolution")
+		return ctrl.Result{}, err
+	}
+
+	// Build new desired status (IMPORTANT: no append)
+	var ips []net.IP
+	for _, addr := range addrs {
+		if ip := net.ParseIP(addr); ip != nil {
+			ips = append(ips, ip)
+		}
+	}
+
+	slices.SortStableFunc(ips, func(a, b net.IP) int {
+		for i := range 15 {
+			if a[i] < b[i] {
+				return -1
+			}
+
+			if a[i] > b[i] {
+				return 1
+			}
+		}
+
+		return 0
+	})
+
+	// check if both ip address slices are the same
+	if slices.EqualFunc(patchBase.Status.IPAddresses, ips, func(s1, s2 net.IP) bool {
+		return bytes.Equal(s1, s2)
+	}) {
+		return ctrl.Result{}, nil
+	}
+
+	log.Info(fmt.Sprintf("found the following IP addresses: %v", ips))
+
+	resolution.Status.IPAddresses = ips
+
+	// Only patch status (clean + minimal diff)
+	if err := r.Status().Patch(
+		ctx,
+		&resolution,
+		client.MergeFrom(patchBase),
+	); err != nil {
+		return ctrl.Result{}, err
+	}
+
+	return ctrl.Result{}, nil
+
+	// if err := r.Patch(ctx, &resolution, client.Merge); err != nil {
+	// 	return ctrl.Result{}, err
+	// }
+
+	// r := &net.Resolver{
+	// 	PreferGo: true,
+	// 	Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
+	// 		d := net.Dialer{
+	// 			Timeout: time.Millisecond * time.Duration(10000),
+	// 		}
+	// 		return d.DialContext(ctx, network, "8.8.8.8:53")
+	// 	},
+	// }
+	// ip, _ := r.LookupHost(context.Background(), "www.google.com")
+}
+
+// SetupWithManager sets up the controller with the Manager.
+func (r *ResolutionReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	return ctrl.NewControllerManagedBy(mgr).
+		For(&dnsv1.Resolution{}).
+		Named("resolution").
+		Complete(r)
+}