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server.go
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server.go
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package app
import (
"context"
"crypto/tls"
"crypto/x509"
"fmt"
"io/ioutil"
"net"
"net/http"
"net/http/pprof"
"os"
"os/signal"
"path/filepath"
"runtime"
"sync"
"syscall"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/spf13/cobra"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/keepalive"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/klog/v2"
"sigs.k8s.io/apiserver-network-proxy/cmd/server/app/options"
"sigs.k8s.io/apiserver-network-proxy/konnectivity-client/proto/client"
"sigs.k8s.io/apiserver-network-proxy/pkg/server"
"sigs.k8s.io/apiserver-network-proxy/pkg/util"
"sigs.k8s.io/apiserver-network-proxy/proto/agent"
)
var udsListenerLock sync.Mutex
func NewProxyCommand(p *Proxy, o *options.ProxyRunOptions) *cobra.Command {
cmd := &cobra.Command{
Use: "proxy",
Long: `A gRPC proxy server, receives requests from the API server and forwards to the agent.`,
RunE: func(cmd *cobra.Command, args []string) error {
return p.run(o)
},
}
return cmd
}
type Proxy struct {
}
type StopFunc func()
func (p *Proxy) run(o *options.ProxyRunOptions) error {
o.Print()
if err := o.Validate(); err != nil {
return fmt.Errorf("failed to validate server options with %v", err)
}
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
var k8sClient *kubernetes.Clientset
if o.AgentNamespace != "" {
config, err := clientcmd.BuildConfigFromFlags("", o.KubeconfigPath)
if err != nil {
return fmt.Errorf("failed to load kubernetes client config: %v", err)
}
if o.KubeconfigQPS != 0 {
klog.V(1).Infof("Setting k8s client QPS: %v", o.KubeconfigQPS)
config.QPS = o.KubeconfigQPS
}
if o.KubeconfigBurst != 0 {
klog.V(1).Infof("Setting k8s client Burst: %v", o.KubeconfigBurst)
config.Burst = o.KubeconfigBurst
}
k8sClient, err = kubernetes.NewForConfig(config)
if err != nil {
return fmt.Errorf("failed to create kubernetes clientset: %v", err)
}
}
authOpt := &server.AgentTokenAuthenticationOptions{
Enabled: o.AgentNamespace != "",
AgentNamespace: o.AgentNamespace,
AgentServiceAccount: o.AgentServiceAccount,
KubernetesClient: k8sClient,
AuthenticationAudience: o.AuthenticationAudience,
}
klog.V(1).Infoln("Starting frontend server for client connections.")
ps, err := server.GenProxyStrategiesFromStr(o.ProxyStrategies)
if err != nil {
return err
}
server := server.NewProxyServer(o.ServerID, ps, int(o.ServerCount), authOpt)
frontendStop, err := p.runFrontendServer(ctx, o, server)
if err != nil {
return fmt.Errorf("failed to run the frontend server: %v", err)
}
klog.V(1).Infoln("Starting agent server for tunnel connections.")
err = p.runAgentServer(o, server)
if err != nil {
return fmt.Errorf("failed to run the agent server: %v", err)
}
klog.V(1).Infoln("Starting admin server for debug connections.")
err = p.runAdminServer(o, server)
if err != nil {
return fmt.Errorf("failed to run the admin server: %v", err)
}
klog.V(1).Infoln("Starting health server for healthchecks.")
err = p.runHealthServer(o, server)
if err != nil {
return fmt.Errorf("failed to run the health server: %v", err)
}
stopCh := SetupSignalHandler()
<-stopCh
klog.V(1).Infoln("Shutting down server.")
if frontendStop != nil {
frontendStop()
}
return nil
}
var shutdownSignals = []os.Signal{os.Interrupt, syscall.SIGTERM}
func SetupSignalHandler() (stopCh <-chan struct{}) {
stop := make(chan struct{})
c := make(chan os.Signal, 2)
signal.Notify(c, shutdownSignals...)
go func() {
<-c
close(stop)
<-c
os.Exit(1) // second signal. Exit directly.
}()
return stop
}
func getUDSListener(ctx context.Context, udsName string) (net.Listener, error) {
udsListenerLock.Lock()
defer udsListenerLock.Unlock()
oldUmask := syscall.Umask(0007)
defer syscall.Umask(oldUmask)
var lc net.ListenConfig
lis, err := lc.Listen(ctx, "unix", udsName)
if err != nil {
return nil, fmt.Errorf("failed to listen(unix) name %s: %v", udsName, err)
}
return lis, nil
}
func (p *Proxy) runFrontendServer(ctx context.Context, o *options.ProxyRunOptions, server *server.ProxyServer) (StopFunc, error) {
if o.UdsName != "" {
return p.runUDSFrontendServer(ctx, o, server)
}
return p.runMTLSFrontendServer(ctx, o, server)
}
func (p *Proxy) runUDSFrontendServer(ctx context.Context, o *options.ProxyRunOptions, s *server.ProxyServer) (StopFunc, error) {
if o.DeleteUDSFile {
if err := os.Remove(o.UdsName); err != nil && !os.IsNotExist(err) {
klog.ErrorS(err, "failed to delete file", "file", o.UdsName)
}
}
var stop StopFunc
if o.Mode == "grpc" {
grpcServer := grpc.NewServer()
client.RegisterProxyServiceServer(grpcServer, s)
lis, err := getUDSListener(ctx, o.UdsName)
if err != nil {
return nil, fmt.Errorf("failed to get uds listener: %v", err)
}
go grpcServer.Serve(lis)
stop = grpcServer.GracefulStop
} else {
// http-connect
server := &http.Server{
Handler: &server.Tunnel{
Server: s,
},
}
stop = func() {
err := server.Shutdown(ctx)
klog.ErrorS(err, "error shutting down server")
}
go func() {
udsListener, err := getUDSListener(ctx, o.UdsName)
if err != nil {
klog.ErrorS(err, "failed to get uds listener")
}
defer func() {
err := udsListener.Close()
klog.ErrorS(err, "failed to close uds listener")
}()
err = server.Serve(udsListener)
if err != nil {
klog.ErrorS(err, "failed to serve uds requests")
}
}()
}
return stop, nil
}
func (p *Proxy) getTLSConfig(caFile, certFile, keyFile string) (*tls.Config, error) {
cert, err := tls.LoadX509KeyPair(certFile, keyFile)
if err != nil {
return nil, fmt.Errorf("failed to load X509 key pair %s and %s: %v", certFile, keyFile, err)
}
if caFile == "" {
return &tls.Config{Certificates: []tls.Certificate{cert}, MinVersion: tls.VersionTLS12}, nil
}
certPool := x509.NewCertPool()
caCert, err := ioutil.ReadFile(filepath.Clean(caFile))
if err != nil {
return nil, fmt.Errorf("failed to read cluster CA cert %s: %v", caFile, err)
}
ok := certPool.AppendCertsFromPEM(caCert)
if !ok {
return nil, fmt.Errorf("failed to append cluster CA cert to the cert pool")
}
tlsConfig := &tls.Config{
ClientAuth: tls.RequireAndVerifyClientCert,
Certificates: []tls.Certificate{cert},
ClientCAs: certPool,
MinVersion: tls.VersionTLS12,
}
return tlsConfig, nil
}
func (p *Proxy) runMTLSFrontendServer(ctx context.Context, o *options.ProxyRunOptions, s *server.ProxyServer) (StopFunc, error) {
var stop StopFunc
var tlsConfig *tls.Config
var err error
if tlsConfig, err = p.getTLSConfig(o.ServerCaCert, o.ServerCert, o.ServerKey); err != nil {
return nil, err
}
addr := fmt.Sprintf(":%d", o.ServerPort)
if o.Mode == "grpc" {
frontendServerOptions := []grpc.ServerOption{
grpc.Creds(credentials.NewTLS(tlsConfig)),
grpc.KeepaliveParams(keepalive.ServerParameters{Time: o.FrontendKeepaliveTime}),
}
grpcServer := grpc.NewServer(frontendServerOptions...)
client.RegisterProxyServiceServer(grpcServer, s)
lis, err := net.Listen("tcp", addr)
if err != nil {
return nil, fmt.Errorf("failed to listen on %s: %v", addr, err)
}
go grpcServer.Serve(lis)
stop = grpcServer.GracefulStop
} else {
// http-connect with no tls
httpServer := &http.Server{
Addr: ":8088",
Handler: &server.Tunnel{
Server: s,
},
}
// http-connect
server := &http.Server{
Addr: addr,
TLSConfig: tlsConfig,
Handler: &server.Tunnel{
Server: s,
},
TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)),
}
stop = func() {
err := server.Shutdown(ctx)
if err != nil {
klog.ErrorS(err, "failed to shutdown server")
}
err = httpServer.Shutdown(ctx)
if err != nil {
klog.ErrorS(err, "failed to shutdown httpServer")
}
}
go func() {
err := server.ListenAndServeTLS("", "") // empty files defaults to tlsConfig
if err != nil {
klog.ErrorS(err, "failed to listen on frontend port")
}
}()
go func() {
err := httpServer.ListenAndServe()
if err != nil {
klog.ErrorS(err, "failed to listen on http master port")
}
}()
}
return stop, nil
}
func (p *Proxy) runAgentServer(o *options.ProxyRunOptions, server *server.ProxyServer) error {
var tlsConfig *tls.Config
var err error
if tlsConfig, err = p.getTLSConfig(o.ClusterCaCert, o.ClusterCert, o.ClusterKey); err != nil {
return err
}
addr := fmt.Sprintf(":%d", o.AgentPort)
agentServerOptions := []grpc.ServerOption{
grpc.Creds(credentials.NewTLS(tlsConfig)),
grpc.KeepaliveParams(keepalive.ServerParameters{Time: o.KeepaliveTime}),
}
grpcServer := grpc.NewServer(agentServerOptions...)
agent.RegisterAgentServiceServer(grpcServer, server)
lis, err := net.Listen("tcp", addr)
if err != nil {
return fmt.Errorf("failed to listen on %s: %v", addr, err)
}
go grpcServer.Serve(lis)
return nil
}
func (p *Proxy) runAdminServer(o *options.ProxyRunOptions, server *server.ProxyServer) error {
muxHandler := http.NewServeMux()
muxHandler.Handle("/metrics", promhttp.Handler())
if o.EnableProfiling {
muxHandler.HandleFunc("/debug/pprof", util.RedirectTo("/debug/pprof/"))
muxHandler.HandleFunc("/debug/pprof/", pprof.Index)
if o.EnableContentionProfiling {
runtime.SetBlockProfileRate(1)
}
}
adminServer := &http.Server{
Addr: fmt.Sprintf("127.0.0.1:%d", o.AdminPort),
Handler: muxHandler,
MaxHeaderBytes: 1 << 20,
}
go func() {
err := adminServer.ListenAndServe()
if err != nil {
klog.ErrorS(err, "admin server could not listen")
}
klog.V(1).Infoln("Admin server stopped listening")
}()
return nil
}
func (p *Proxy) runHealthServer(o *options.ProxyRunOptions, server *server.ProxyServer) error {
livenessHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "ok")
})
readinessHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ready, msg := server.Readiness.Ready()
if ready {
w.WriteHeader(200)
fmt.Fprintf(w, "ok")
return
}
w.WriteHeader(500)
fmt.Fprintf(w, msg)
})
muxHandler := http.NewServeMux()
muxHandler.HandleFunc("/healthz", livenessHandler)
// "/ready" is deprecated but being maintained for backward compatibility
muxHandler.HandleFunc("/ready", readinessHandler)
muxHandler.HandleFunc("/readyz", readinessHandler)
healthServer := &http.Server{
Addr: fmt.Sprintf(":%d", o.HealthPort),
Handler: muxHandler,
MaxHeaderBytes: 1 << 20,
}
go func() {
err := healthServer.ListenAndServe()
if err != nil {
klog.ErrorS(err, "health server could not listen")
}
klog.V(1).Infoln("Health server stopped listening")
}()
return nil
}