Deprecate the klog flags deprecated in Kubernetes 1.23

In order to display deprecation warnings, I swapped "flag" with "pflag".
We already import pflag, so I thought it would not be an issue.

Signed-off-by: Maël Valais <mael@vls.dev>

cmd/cainjector/main.go

@@ -27,6 +27,7 @@ import (
 	"github.com/cert-manager/cert-manager/cmd/cainjector/app"
 	"github.com/cert-manager/cert-manager/internal/cmd/util"
 	logf "github.com/cert-manager/cert-manager/pkg/logs"
+	"github.com/spf13/pflag"
 )
 
 func main() {
@@ -35,7 +36,7 @@ func main() {
 	stopCh, exit := util.SetupExitHandler(util.GracefulShutdown)
 	defer exit() // This function might call os.Exit, so defer last
 
-	logf.InitLogs(flag.CommandLine)
+	logf.InitLogs(pflag.CommandLine)
 	defer logf.FlushLogs()
 	ctrl.SetLogger(logf.Log)
 

cmd/controller/main.go

@@ -17,24 +17,23 @@ limitations under the License.
 package main
 
 import (
-	"flag"
-
 	"github.com/cert-manager/cert-manager/cmd/controller/app"
 	"github.com/cert-manager/cert-manager/internal/cmd/util"
 	logf "github.com/cert-manager/cert-manager/pkg/logs"
+	"github.com/spf13/pflag"
 )
 
 func main() {
 	stopCh, exit := util.SetupExitHandler(util.GracefulShutdown)
 	defer exit() // This function might call os.Exit, so defer last
 
-	logf.InitLogs(flag.CommandLine)
+	logf.InitLogs(pflag.CommandLine)
 	defer logf.FlushLogs()
 
 	cmd := app.NewCommandStartCertManagerController(stopCh)
-	cmd.Flags().AddGoFlagSet(flag.CommandLine)
+	cmd.Flags().AddFlagSet(pflag.CommandLine)
 
-	flag.CommandLine.Parse([]string{})
+	pflag.CommandLine.Parse([]string{})
 	if err := cmd.Execute(); err != nil {
 		logf.Log.Error(err, "error while executing")
 		util.SetExitCode(err)

cmd/webhook/app/options/globalflags.go

@@ -17,7 +17,6 @@ limitations under the License.
 package options
 
 import (
-	"flag"
 	"os"
 
 	"github.com/spf13/pflag"
@@ -30,7 +29,7 @@ func AddGlobalFlags(fs *pflag.FlagSet) {
 }
 
 func addKlogFlags(fs *pflag.FlagSet) {
-	local := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+	local := pflag.NewFlagSet(os.Args[0], pflag.ExitOnError)
 	logs.InitLogs(local)
-	fs.AddGoFlagSet(local)
+	fs.AddFlagSet(local)
 }

cmd/webhook/main.go

@@ -22,13 +22,14 @@ import (
 	"github.com/cert-manager/cert-manager/cmd/webhook/app"
 	"github.com/cert-manager/cert-manager/internal/cmd/util"
 	logf "github.com/cert-manager/cert-manager/pkg/logs"
+	"github.com/spf13/pflag"
 )
 
 func main() {
 	stopCh, exit := util.SetupExitHandler(util.GracefulShutdown)
 	defer exit() // This function might call os.Exit, so defer last
 
-	logf.InitLogs(flag.CommandLine)
+	logf.InitLogs(pflag.CommandLine)
 	defer logf.FlushLogs()
 
 	cmd := app.NewServerCommand(stopCh)

pkg/controller/test/context_builder.go

@@ -18,7 +18,6 @@ package test
 
 import (
 	"context"
-	"flag"
 	"fmt"
 	"reflect"
 	"testing"
@@ -46,12 +45,13 @@ import (
 	"github.com/cert-manager/cert-manager/pkg/metrics"
 	"github.com/cert-manager/cert-manager/pkg/util"
 	discoveryfake "github.com/cert-manager/cert-manager/test/unit/discovery"
+	"github.com/spf13/pflag"
 )
 
 func init() {
 	logs.InitLogs(nil)
-	_ = flag.Set("alsologtostderr", fmt.Sprintf("%t", true))
-	_ = flag.Lookup("v").Value.Set("4")
+	_ = pflag.Set("alsologtostderr", fmt.Sprintf("%t", true))
+	_ = pflag.Lookup("v").Value.Set("4")
 }
 
 // Builder is a structure used to construct new Contexts for use during tests.

pkg/logs/logs.go

@@ -24,6 +24,7 @@ import (
 	"time"
 
 	"github.com/go-logr/logr"
+	"github.com/spf13/pflag"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -49,7 +50,7 @@ const (
 	TraceLevel        = 5
 )
 
-var logFlushFreq = flag.Duration("log-flush-frequency", 5*time.Second, "Maximum number of seconds between log flushes")
+var logFlushFreq = pflag.Duration("log-flush-frequency", 5*time.Second, "Maximum number of seconds between log flushes")
 
 // GlogWriter serves as a bridge between the standard log package and the glog package.
 type GlogWriter struct{}
@@ -61,16 +62,32 @@ func (writer GlogWriter) Write(data []byte) (n int, err error) {
 }
 
 // InitLogs initializes logs the way we want for kubernetes.
-func InitLogs(fs *flag.FlagSet) {
+func InitLogs(fs *pflag.FlagSet) {
 	if fs == nil {
-		fs = flag.CommandLine
+		fs = pflag.CommandLine
 	}
-	klog.InitFlags(fs)
-	_ = fs.Set("logtostderr", "true")
 
 	log.SetOutput(GlogWriter{})
 	log.SetFlags(0)
 
+	_ = fs.Set("logtostderr", "true")
+
+	// Add the klog flags by converting them to pflags, and mark deprecated
+	// flags.
+	klogflags := flag.NewFlagSet("", flag.ContinueOnError)
+	klog.InitFlags(klogflags)
+	klogflags.VisitAll(func(f *flag.Flag) {
+		pf := pflag.PFlagFromGoFlag(f)
+		switch f.Name {
+		case "v", "vmodule":
+			// Unchanged.
+		default:
+			// Deprecated.
+			pf.Deprecated = fmt.Sprintf("this flag will be removed in cert-manager 1.15")
+		}
+		fs.AddFlag(pf)
+	})
+
 	// The default glog flush interval is 30 seconds, which is frighteningly long.
 	go wait.Until(klog.Flush, *logFlushFreq, wait.NeverStop)
 }

test/acme/dns/fixture.go

@@ -17,7 +17,6 @@ limitations under the License.
 package dns
 
 import (
-	"flag"
 	"fmt"
 	"sync"
 	"testing"
@@ -29,12 +28,13 @@ import (
 
 	"github.com/cert-manager/cert-manager/pkg/acme/webhook"
 	"github.com/cert-manager/cert-manager/test/internal/apiserver"
+	"github.com/spf13/pflag"
 )
 
 func init() {
-	vFlag := flag.Lookup("v")
+	vFlag := pflag.Lookup("v")
 	if vFlag != nil {
-		flag.Set("alsologtostderr", fmt.Sprintf("%t", true))
+		pflag.Set("alsologtostderr", fmt.Sprintf("%t", true))
 		vFlag.Value.Set("12")
 	}
 }

test/e2e/e2e_test.go

@@ -25,14 +25,15 @@ import (
 
 	"github.com/onsi/ginkgo/v2"
 	"github.com/onsi/gomega"
+	"github.com/spf13/pflag"
 	"k8s.io/apimachinery/pkg/util/wait"
 
 	"github.com/cert-manager/cert-manager/pkg/logs"
 	_ "github.com/cert-manager/cert-manager/test/e2e/suite"
 )
 
 func init() {
-	logs.InitLogs(flag.CommandLine)
+	logs.InitLogs(pflag.CommandLine)
 	cfg.AddFlags(flag.CommandLine)
 
 	wait.ForeverTestTimeout = time.Second * 60