add pod_watcher

Signed-off-by: walnuts1018 <r.juglans.1018@gmail.com>

cmd/nat-gateway/main.go

@@ -0,0 +1,163 @@
+package main
+
+import (
+	"crypto/tls"
+	"flag"
+	"os"
+
+	// Import all Kubernetes client auth plugins (e.g. Azure, GCP, OIDC, etc.)
+	// to ensure that exec-entrypoint and run can make use of them.
+	_ "k8s.io/client-go/plugin/pkg/client/auth"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/healthz"
+	"sigs.k8s.io/controller-runtime/pkg/log/zap"
+	"sigs.k8s.io/controller-runtime/pkg/metrics/filters"
+	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
+	"sigs.k8s.io/controller-runtime/pkg/webhook"
+
+	ponav1beta1 "github.com/cybozu-go/pona/api/v1beta1"
+	"github.com/cybozu-go/pona/internal/controller"
+	// +kubebuilder:scaffold:imports
+)
+
+var (
+	scheme   = runtime.NewScheme()
+	setupLog = ctrl.Log.WithName("setup")
+)
+
+func init() {
+	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
+
+	utilruntime.Must(ponav1beta1.AddToScheme(scheme))
+	// +kubebuilder:scaffold:scheme
+}
+
+type Config struct {
+	FoUPort int
+}
+
+func main() {
+	var metricsAddr string
+	var enableLeaderElection bool
+	var probeAddr string
+	var secureMetrics bool
+	var enableHTTP2 bool
+	var tlsOpts []func(*tls.Config)
+
+	var config Config
+
+	flag.StringVar(&metricsAddr, "metrics-bind-address", "0", "The address the metrics endpoint binds to. "+
+		"Use :8443 for HTTPS or :8080 for HTTP, or leave as 0 to disable the metrics service.")
+	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
+	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
+		"Enable leader election for controller manager. "+
+			"Enabling this will ensure there is only one active controller manager.")
+	flag.BoolVar(&secureMetrics, "metrics-secure", true,
+		"If set, the metrics endpoint is served securely via HTTPS. Use --metrics-secure=false to use HTTP instead.")
+	flag.BoolVar(&enableHTTP2, "enable-http2", false,
+		"If set, HTTP/2 will be enabled for the metrics and webhook servers")
+	flag.IntVar(&config.FoUPort, "fou-port", 5555, "port number for foo-over-udp tunnels")
+
+	opts := zap.Options{
+		Development: true,
+	}
+	opts.BindFlags(flag.CommandLine)
+	flag.Parse()
+
+	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))
+
+	// if the enable-http2 flag is false (the default), http/2 should be disabled
+	// due to its vulnerabilities. More specifically, disabling http/2 will
+	// prevent from being vulnerable to the HTTP/2 Stream Cancellation and
+	// Rapid Reset CVEs. For more information see:
+	// - https://github.com/advisories/GHSA-qppj-fm5r-hxr3
+	// - https://github.com/advisories/GHSA-4374-p667-p6c8
+	disableHTTP2 := func(c *tls.Config) {
+		setupLog.Info("disabling http/2")
+		c.NextProtos = []string{"http/1.1"}
+	}
+
+	if !enableHTTP2 {
+		tlsOpts = append(tlsOpts, disableHTTP2)
+	}
+
+	webhookServer := webhook.NewServer(webhook.Options{
+		TLSOpts: tlsOpts,
+	})
+
+	// Metrics endpoint is enabled in 'config/default/kustomization.yaml'. The Metrics options configure the server.
+	// More info:
+	// - https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.18.4/pkg/metrics/server
+	// - https://book.kubebuilder.io/reference/metrics.html
+	metricsServerOptions := metricsserver.Options{
+		BindAddress:   metricsAddr,
+		SecureServing: secureMetrics,
+		// TODO(user): TLSOpts is used to allow configuring the TLS config used for the server. If certificates are
+		// not provided, self-signed certificates will be generated by default. This option is not recommended for
+		// production environments as self-signed certificates do not offer the same level of trust and security
+		// as certificates issued by a trusted Certificate Authority (CA). The primary risk is potentially allowing
+		// unauthorized access to sensitive metrics data. Consider replacing with CertDir, CertName, and KeyName
+		// to provide certificates, ensuring the server communicates using trusted and secure certificates.
+		TLSOpts: tlsOpts,
+	}
+
+	if secureMetrics {
+		// FilterProvider is used to protect the metrics endpoint with authn/authz.
+		// These configurations ensure that only authorized users and service accounts
+		// can access the metrics endpoint. The RBAC are configured in 'config/rbac/kustomization.yaml'. More info:
+		// https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.18.4/pkg/metrics/filters#WithAuthenticationAndAuthorization
+		metricsServerOptions.FilterProvider = filters.WithAuthenticationAndAuthorization
+	}
+
+	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
+		Scheme:                 scheme,
+		Metrics:                metricsServerOptions,
+		WebhookServer:          webhookServer,
+		HealthProbeBindAddress: probeAddr,
+		LeaderElection:         enableLeaderElection,
+		LeaderElectionID:       "7e4aaa0a.pona.cybozu.com",
+		// LeaderElectionReleaseOnCancel defines if the leader should step down voluntarily
+		// when the Manager ends. This requires the binary to immediately end when the
+		// Manager is stopped, otherwise, this setting is unsafe. Setting this significantly
+		// speeds up voluntary leader transitions as the new leader don't have to wait
+		// LeaseDuration time first.
+		//
+		// In the default scaffold provided, the program ends immediately after
+		// the manager stops, so would be fine to enable this option. However,
+		// if you are doing or is intended to do any operation such as perform cleanups
+		// after the manager stops then its usage might be unsafe.
+		// LeaderElectionReleaseOnCancel: true,
+	})
+	if err != nil {
+		setupLog.Error(err, "unable to start manager")
+		os.Exit(1)
+	}
+
+	if err = (&controller.PodReconciler{
+		Client: mgr.GetClient(),
+		Scheme: mgr.GetScheme(),
+	}).SetupWithManager(mgr); err != nil {
+		setupLog.Error(err, "unable to create controller", "controller", "Pod")
+		os.Exit(1)
+	}
+	// +kubebuilder:scaffold:builder
+
+	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {
+		setupLog.Error(err, "unable to set up health check")
+		os.Exit(1)
+	}
+	if err := mgr.AddReadyzCheck("readyz", healthz.Ping); err != nil {
+		setupLog.Error(err, "unable to set up ready check")
+		os.Exit(1)
+	}
+
+	setupLog.Info("starting manager")
+	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
+		setupLog.Error(err, "problem running manager")
+		os.Exit(1)
+	}
+}

internal/controller/pod_watcher.go

@@ -0,0 +1,86 @@
+package controller
+
+import (
+	"context"
+	"strings"
+
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+)
+
+const (
+	EgressAnnotationPrefix = "egress.pona.cybozu.com/"
+)
+
+// PodReconciler reconciles a Pod object
+type PodReconciler struct {
+	client.Client
+	Scheme *runtime.Scheme
+
+	EgressName      string
+	EgressNamespace string
+}
+
+// +kubebuilder:rbac:groups=core,resources=pods,verbs=get;list;watch
+
+// 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 Pod 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@v0.19.0/pkg/reconcile
+func (r *PodReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
+	logger := log.FromContext(ctx)
+
+	pod := &corev1.Pod{}
+	if err := r.Get(ctx, req.NamespacedName, pod); err != nil {
+
+	}
+
+	return ctrl.Result{}, nil
+}
+
+func (r *PodReconciler) shouldHandle(pod *corev1.Pod) bool {
+	if pod.Spec.HostNetwork {
+		// Egress feature is not available for Pods running in the host network.
+		return false
+	}
+
+	return false
+}
+
+func (r *PodReconciler) hasEgressAnnotation(pod *corev1.Pod) bool {
+	for k, v := range pod.Annotations {
+		if !strings.HasPrefix(k, EgressAnnotationPrefix) {
+			continue
+		}
+
+		if k[len(EgressAnnotationPrefix):] != r.EgressNamespace {
+			continue
+		}
+
+		// shortcut for the most typical case
+		if v == r.myName {
+			return true
+		}
+
+		for _, n := range strings.Split(v, ",") {
+			if n == r.myName {
+				return true
+			}
+		}
+	}
+}
+
+// SetupWithManager sets up the controller with the Manager.
+func (r *PodReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	return ctrl.NewControllerManagedBy(mgr).
+		For(&corev1.Pod{}).
+		Complete(r)
+}

internal/controller/pod_watcher_test.go

@@ -0,0 +1,16 @@
+package controller
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+)
+
+var _ = Describe("Pod Controller", func() {
+	Context("When reconciling a resource", func() {
+
+		It("should successfully reconcile the resource", func() {
+
+			// TODO(user): Add more specific assertions depending on your controller's reconciliation logic.
+			// Example: If you expect a certain status condition after reconciliation, verify it here.
+		})
+	})
+})