Add initial API server proxy

Co-authored-by: Shyam <shyam0904a@users.noreply.github.com>

main.go

@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: BSD-3-Clause
+
+package main
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"golang.org/x/sync/errgroup"
+
+	"github.com/netbirdio/netbird/client/embed"
+	netbird "github.com/netbirdio/netbird/shared/management/client/rest"
+
+	"github.com/netbirdio/netbird-kubeapi-proxy/internal/proxy"
+)
+
+func main() {
+	var (
+		mgmtURL       string
+		apiKey        string
+		setupKey      string
+		kubeAPIServer string
+		instanceName  string
+		clusterName   string
+	)
+	flag.StringVar(&mgmtURL, "management-url", "https://api.netbird.io", "NetBird management URL")
+	flag.StringVar(&apiKey, "api-key", os.Getenv("NB_API_KEY"), "NetBird API key")
+	flag.StringVar(&setupKey, "setup-key", os.Getenv("NB_SETUP_KEY"), "NetBird setup key")
+	flag.StringVar(&kubeAPIServer, "kubernetes-api-server", "https://kubernetes.default.svc.cluster.local", "Target Kubernetes API server URL")
+	flag.StringVar(&instanceName, "instance-name", "", "Name of the instance")
+	flag.StringVar(&clusterName, "cluster-name", "", "Name of the cluster")
+	flag.Parse()
+
+	err := run(context.Background(), kubeAPIServer, mgmtURL, apiKey, setupKey, instanceName, clusterName)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func run(ctx context.Context, kubeAPIServer, mgmtURL, apiKey, setupKey, instanceName, clusterName string) error {
+	ctx, cancel := signal.NotifyContext(ctx, syscall.SIGTERM)
+	defer cancel()
+	g, gCtx := errgroup.WithContext(ctx)
+
+	kubeAPIServerURL, err := url.Parse(kubeAPIServer)
+	if err != nil {
+		return err
+	}
+	if kubeAPIServerURL.Scheme != "https" || kubeAPIServerURL.Host == "" {
+		return errors.New("kubernetes-api-server must be an absolute https URL")
+	}
+
+	netbirdClient := netbird.NewWithOptions(
+		netbird.WithManagementURL(mgmtURL),
+		netbird.WithBearerToken(apiKey),
+	)
+
+	opts := embed.Options{
+		ManagementURL: mgmtURL,
+		SetupKey:      setupKey,
+		DeviceName:    instanceName,
+		LogOutput:     io.Discard,
+		DNSLabels:     []string{clusterName + "." + "netbird-kubeapi-proxy"},
+	}
+	embedClient, err := embed.New(opts)
+	if err != nil {
+		return err
+	}
+	err = embedClient.Start(ctx)
+	if err != nil {
+		return err
+	}
+	g.Go(func() error {
+		<-gCtx.Done()
+		return embedClient.Stop(context.Background())
+	})
+
+	proxySrv, err := proxy.Server(embedClient, netbirdClient, kubeAPIServerURL)
+	if err != nil {
+		return err
+	}
+	listener, err := embedClient.ListenTCP(":443")
+	if err != nil {
+		return err
+	}
+	g.Go(func() error {
+		err := proxySrv.ServeTLS(listener, "", "")
+		if err != nil && !errors.Is(err, http.ErrServerClosed) {
+			return err
+		}
+		return nil
+	})
+	g.Go(func() error {
+		<-gCtx.Done()
+		return proxySrv.Shutdown(context.Background())
+	})
+
+	err = g.Wait()
+	if err != nil {
+		return err
+	}
+	return nil
+}