refactor: replace klog with slog

.golangci.yaml

@@ -3,9 +3,8 @@ run:
   modules-download-mode: readonly
 linters:
   enable:
-  - exhaustive
-  - exportloopref
   - dupl
+  - exportloopref
   - gochecknoinits
   - goconst
   - gocritic
@@ -22,10 +21,6 @@ linters:
   - usestdlibvars
   - whitespace
 linters-settings:
-  exhaustive:
-    # presence of "default" case in switch statements satisfies exhaustiveness,
-    # even if all enum members are not listed
-    default-signifies-exhaustive: true
 issues:
   exclude-rules:
   - path: _test.go

cmd/client/forwarder.go

@@ -2,15 +2,16 @@ package main
 
 import (
 	"fmt"
+	"log/slog"
 	"net"
 	"strconv"
 
 	"k8s.io/apimachinery/pkg/util/httpstream"
-	"k8s.io/klog/v2"
 
 	"github.com/knight42/krelay/pkg/constants"
 	"github.com/knight42/krelay/pkg/ports"
 	"github.com/knight42/krelay/pkg/remoteaddr"
+	slogutil "github.com/knight42/krelay/pkg/slog"
 	"github.com/knight42/krelay/pkg/xnet"
 )
 
@@ -53,14 +54,16 @@ func (p *portForwarder) listen(localIP string) error {
 func (p *portForwarder) run(streamConn httpstream.Connection) {
 	switch {
 	case p.tcpListener != nil:
-		l := p.tcpListener
-		defer l.Close()
-
-		localAddr := l.Addr().String()
-		klog.InfoS("Forwarding",
-			constants.LogFieldProtocol, p.ports.Protocol,
-			constants.LogFieldLocalAddr, localAddr,
-			constants.LogFieldRemotePort, p.ports.RemotePort,
+		lis := p.tcpListener
+		defer lis.Close()
+
+		localAddr := lis.Addr().String()
+		l := slog.With(
+			slog.String(constants.LogFieldProtocol, p.ports.Protocol),
+			slog.String(constants.LogFieldLocalAddr, localAddr),
+		)
+		l.Info("Forwarding",
+			slogutil.Uint16(constants.LogFieldRemotePort, p.ports.RemotePort),
 		)
 
 		for {
@@ -70,21 +73,15 @@ func (p *portForwarder) run(streamConn httpstream.Connection) {
 			default:
 			}
 
-			c, err := l.Accept()
+			c, err := lis.Accept()
 			if err != nil {
-				klog.ErrorS(err, "Fail to accept tcp connection",
-					constants.LogFieldProtocol, p.ports.Protocol,
-					constants.LogFieldLocalAddr, localAddr,
-				)
+				l.Error("Fail to accept tcp connection", slogutil.Error(err))
 				return
 			}
 
 			remoteAddr, err := p.addrGetter.Get()
 			if err != nil {
-				klog.ErrorS(err, "Fail to get remote address",
-					constants.LogFieldProtocol, p.ports.Protocol,
-					constants.LogFieldLocalAddr, localAddr,
-				)
+				l.Error("Fail to get remote address", slogutil.Error(err))
 				continue
 			}
 			go handleTCPConn(c, streamConn, remoteAddr, p.ports.RemotePort)
@@ -96,21 +93,21 @@ func (p *portForwarder) run(streamConn httpstream.Connection) {
 
 		udpConn := &xnet.UDPConn{UDPConn: pc.(*net.UDPConn)}
 		localAddr := pc.LocalAddr().String()
-		klog.InfoS("Forwarding",
-			constants.LogFieldProtocol, p.ports.Protocol,
-			constants.LogFieldLocalAddr, localAddr,
-			constants.LogFieldRemotePort, p.ports.RemotePort,
+		l := slog.With(
+			slog.String(constants.LogFieldProtocol, p.ports.Protocol),
+			slog.String(constants.LogFieldLocalAddr, localAddr),
+		)
+		l.Info("Forwarding",
+			slogutil.Uint16(constants.LogFieldRemotePort, p.ports.RemotePort),
 		)
 		track := newConnTrack()
 		finish := make(chan string)
 
 		go func() {
 			for key := range finish {
 				track.Delete(key)
-				klog.V(4).InfoS("Remove udp conn from conntrack table",
-					"key", key,
-					constants.LogFieldProtocol, p.ports.Protocol,
-					constants.LogFieldLocalAddr, localAddr,
+				l.Debug("Remove udp conn from conntrack table",
+					slog.String("key", key),
 				)
 			}
 		}()
@@ -128,9 +125,8 @@ func (p *portForwarder) run(streamConn httpstream.Connection) {
 
 			n, cliAddr, err := udpConn.ReadFrom(buf)
 			if err != nil {
-				klog.ErrorS(err, "Fail to read udp packet",
-					constants.LogFieldProtocol, p.ports.Protocol,
-					constants.LogFieldLocalAddr, localAddr,
+				l.Error("Fail to read udp packet",
+					slogutil.Error(err),
 				)
 				return
 			}
@@ -146,9 +142,8 @@ func (p *portForwarder) run(streamConn httpstream.Connection) {
 				track.Set(key, dataCh)
 				remoteAddr, err := p.addrGetter.Get()
 				if err != nil {
-					klog.ErrorS(err, "Fail to get remote address",
-						constants.LogFieldProtocol, p.ports.Protocol,
-						constants.LogFieldLocalAddr, localAddr,
+					l.Error("Fail to get remote address",
+						slogutil.Error(err),
 					)
 					continue
 				}

cmd/client/main.go

@@ -4,8 +4,8 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
-	"flag"
 	"fmt"
+	"log/slog"
 	"net/http"
 	"os"
 	"os/signal"
@@ -22,11 +22,11 @@ import (
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/transport/spdy"
-	"k8s.io/klog/v2"
 
 	"github.com/knight42/krelay/pkg/constants"
 	"github.com/knight42/krelay/pkg/ports"
 	"github.com/knight42/krelay/pkg/remoteaddr"
+	slogutil "github.com/knight42/krelay/pkg/slog"
 	"github.com/knight42/krelay/pkg/xnet"
 )
 
@@ -41,6 +41,8 @@ type Options struct {
 	address string
 	// targetsFile is the file containing the list of targets.
 	targetsFile string
+
+	verbosity int
 }
 
 // setKubernetesDefaults sets default values on the provided client config for accessing the Kubernetes API.
@@ -153,7 +155,7 @@ func (o *Options) Run(ctx context.Context, args []string) error {
 		}
 	}
 
-	klog.InfoS("Creating krelay-server", "namespace", o.serverNamespace)
+	slog.Info("Creating krelay-server", slog.String("namespace", o.serverNamespace))
 	svrPodName, err := createServerPod(ctx, cs, o.serverImage, o.serverNamespace)
 	if err != nil {
 		return fmt.Errorf("create krelay-server pod: %w", err)
@@ -164,7 +166,7 @@ func (o *Options) Run(ctx context.Context, args []string) error {
 	if err != nil {
 		return fmt.Errorf("ensure krelay-server is running: %w", err)
 	}
-	klog.InfoS("krelay-server is running", "pod", svrPodName, "namespace", o.serverNamespace)
+	slog.Info("krelay-server is running", slog.String("pod", svrPodName), slog.String("namespace", o.serverNamespace))
 
 	transport, upgrader, err := spdy.RoundTripperFor(restCfg)
 	if err != nil {
@@ -191,7 +193,7 @@ func (o *Options) Run(ctx context.Context, args []string) error {
 	for _, pf := range portForwarders {
 		err := pf.listen(o.address)
 		if err != nil {
-			klog.ErrorS(err, "Fail to listen on port", "port", pf.ports.LocalPort)
+			slog.Error("Fail to listen on port", slog.Any("port", pf.ports.LocalPort), slog.Any("error", err))
 		} else {
 			succeeded = true
 		}
@@ -204,15 +206,14 @@ func (o *Options) Run(ctx context.Context, args []string) error {
 
 	select {
 	case <-streamConn.CloseChan():
-		klog.InfoS("Lost connection to krelay-server pod")
+		slog.Info("Lost connection to krelay-server pod")
 	case <-ctx.Done():
 	}
 
 	return nil
 }
 
 func main() {
-	klog.InitFlags(nil)
 	cf := genericclioptions.NewConfigFlags(true)
 	o := Options{
 		getter: cf,
@@ -237,40 +238,29 @@ service, ip and hostname rather than only pods.`,
 				})
 			}
 
+			h := slog.NewTextHandler(cmd.ErrOrStderr(), &slog.HandlerOptions{
+				Level: slogutil.MapVerbosityToLogLevel(o.verbosity),
+			})
+			slog.SetDefault(slog.New(h))
 			ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
 			defer cancel()
 			return o.Run(ctx, args)
 		},
 		SilenceUsage: true,
 	}
 	flags := c.Flags()
-	flags.AddGoFlagSet(flag.CommandLine)
-	cf.AddFlags(flags)
+	flags.SortFlags = false
+	flags.StringVar(cf.KubeConfig, "kubeconfig", *cf.KubeConfig, "Path to the kubeconfig file to use for CLI requests.")
+	flags.StringVarP(cf.Namespace, "namespace", "n", *cf.Namespace, "If present, the namespace scope for this CLI request")
+	flags.StringVar(cf.Context, "context", *cf.Context, "The name of the kubeconfig context to use")
+	flags.StringVar(cf.ClusterName, "cluster", *cf.ClusterName, "The name of the kubeconfig cluster to use")
+
 	flags.BoolVarP(&printVersion, "version", "V", false, "Print version info and exit.")
 	flags.StringVar(&o.address, "address", "127.0.0.1", "Address to listen on. Only accepts IP addresses as a value.")
+	flags.StringVarP(&o.targetsFile, "file", "f", "", "Forward to the targets specified in the given file, with one target per line.")
 	flags.StringVar(&o.serverImage, "server.image", "ghcr.io/knight42/krelay-server:v0.0.2", "The krelay-server image to use.")
 	flags.StringVar(&o.serverNamespace, "server.namespace", metav1.NamespaceDefault, "The namespace in which krelay-server is located.")
-	flags.StringVarP(&o.targetsFile, "file", "f", "", "Forward to the targets specified in the given file, with one target per line.")
-
-	// I do not want these flags to show up in --help.
-	hiddenFlags := []string{
-		"add_dir_header",
-		"log_flush_frequency",
-		"alsologtostderr",
-		"log_backtrace_at",
-		"log_dir",
-		"log_file",
-		"log_file_max_size",
-		"one_output",
-		"logtostderr",
-		"skip_headers",
-		"skip_log_headers",
-		"stderrthreshold",
-		"vmodule",
-	}
-	for _, flagName := range hiddenFlags {
-		_ = flags.MarkHidden(flagName)
-	}
+	flags.IntVarP(&o.verbosity, "v", "v", 3, "Number for the log level verbosity. The bigger the more verbose.")
 
 	_ = c.Execute()
 }

cmd/client/tcp.go

@@ -2,12 +2,13 @@ package main
 
 import (
 	"io"
+	"log/slog"
 	"net"
 
 	"k8s.io/apimachinery/pkg/util/httpstream"
-	"k8s.io/klog/v2"
 
 	"github.com/knight42/krelay/pkg/constants"
+	slogutil "github.com/knight42/krelay/pkg/slog"
 	"github.com/knight42/krelay/pkg/xio"
 	"github.com/knight42/krelay/pkg/xnet"
 )
@@ -16,18 +17,17 @@ func handleTCPConn(clientConn net.Conn, serverConn httpstream.Connection, dstAdd
 	defer clientConn.Close()
 
 	requestID := xnet.NewRequestID()
-	kvs := []any{constants.LogFieldRequestID, requestID}
-	defer klog.V(4).InfoS("handleTCPConn exit", kvs...)
-	klog.InfoS("Handling tcp connection",
-		constants.LogFieldRequestID, requestID,
-		constants.LogFieldDestAddr, xnet.JoinHostPort(dstAddr.String(), dstPort),
-		constants.LogFieldLocalAddr, clientConn.LocalAddr().String(),
-		"clientAddr", clientConn.RemoteAddr().String(),
+	l := slog.With(slog.String(constants.LogFieldRequestID, requestID))
+	defer l.Debug("handleTCPConn exit")
+	l.Info("Handling tcp connection",
+		slog.String(constants.LogFieldDestAddr, xnet.JoinHostPort(dstAddr.String(), dstPort)),
+		slog.String(constants.LogFieldLocalAddr, clientConn.LocalAddr().String()),
+		slog.String("clientAddr", clientConn.RemoteAddr().String()),
 	)
 
 	dataStream, errorChan, err := createStream(serverConn, requestID)
 	if err != nil {
-		klog.ErrorS(err, "Fail to create stream", kvs...)
+		l.Error("Fail to create stream", slogutil.Error(err))
 		return
 	}
 
@@ -39,18 +39,18 @@ func handleTCPConn(clientConn net.Conn, serverConn httpstream.Connection, dstAdd
 	}
 	_, err = xio.WriteFull(dataStream, hdr.Marshal())
 	if err != nil {
-		klog.ErrorS(err, "Fail to write header", kvs...)
+		l.Error("Fail to write header", slogutil.Error(err))
 		return
 	}
 
 	var ack xnet.Acknowledgement
 	err = ack.FromReader(dataStream)
 	if err != nil {
-		klog.ErrorS(err, "Fail to receive ack", kvs...)
+		l.Error("Fail to receive ack", slogutil.Error(err))
 		return
 	}
 	if ack.Code != xnet.AckCodeOK {
-		klog.ErrorS(ack.Code, "Fail to connect", kvs...)
+		l.Error("Fail to connect", slogutil.Error(ack.Code))
 		return
 	}
 
@@ -60,7 +60,7 @@ func handleTCPConn(clientConn net.Conn, serverConn httpstream.Connection, dstAdd
 	go func() {
 		// Copy from the remote side to the local port.
 		if _, err := io.Copy(clientConn, dataStream); err != nil && !xnet.IsClosedConnectionError(err) {
-			klog.ErrorS(err, "Fail to copy from remote stream to local connection", kvs...)
+			l.Error("Fail to copy from remote stream to local connection", slogutil.Error(err))
 		}
 
 		// inform the select below that the remote copy is done
@@ -73,7 +73,7 @@ func handleTCPConn(clientConn net.Conn, serverConn httpstream.Connection, dstAdd
 
 		// Copy from the local port to the remote side.
 		if _, err := io.Copy(dataStream, clientConn); err != nil && !xnet.IsClosedConnectionError(err) {
-			klog.ErrorS(err, "Fail to copy from local connection to remote stream", kvs...)
+			l.Error("Fail to copy from local connection to remote stream", slogutil.Error(err))
 			// break out of the select below without waiting for the other copy to finish
 			close(localError)
 		}
@@ -88,6 +88,6 @@ func handleTCPConn(clientConn net.Conn, serverConn httpstream.Connection, dstAdd
 	// always expect something on errorChan (it may be nil)
 	err = <-errorChan
 	if err != nil {
-		klog.ErrorS(err, "Unexpected error from stream", kvs...)
+		l.Error("Unexpected error from stream", slogutil.Error(err))
 	}
 }