feat: support flagsets in internal cmd package (#5461)

* feat: add signal in internal cmd package

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

* logger

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

* feat: support flagsets in internal cmd package

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

* setup

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

* setup

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

* init container

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>
Co-authored-by: Vyankatesh Kudtarkar <vyankateshkd@gmail.com>

cmd/cleanup-controller/main.go

@@ -32,16 +32,6 @@ const (
 	resyncPeriod = 15 * time.Minute
 )
 
-func parseFlags(config internal.Configuration) {
-	internal.InitFlags(config)
-	flag.StringVar(&otel, "otelConfig", "prometheus", "Set this flag to 'grpc', to enable exporting metrics to an Opentelemetry Collector. The default collector is set to \"prometheus\"")
-	flag.StringVar(&otelCollector, "otelCollector", "opentelemetrycollector.kyverno.svc.cluster.local", "Set this flag to the OpenTelemetry Collector Service Address. Kyverno will try to connect to this on the metrics port.")
-	flag.StringVar(&transportCreds, "transportCreds", "", "Set this flag to the CA secret containing the certificate which is used by our Opentelemetry Metrics Client. If empty string is set, means an insecure connection will be used")
-	flag.StringVar(&metricsPort, "metricsPort", "8000", "Expose prometheus metrics at the given port, default to 8000.")
-	flag.BoolVar(&disableMetricsExport, "disableMetrics", false, "Set this flag to 'true' to disable metrics.")
-	flag.Parse()
-}
-
 func setupMetrics(logger logr.Logger, kubeClient kubernetes.Interface) (*metrics.MetricsConfig, context.CancelFunc, error) {
 	logger = logger.WithName("metrics")
 	logger.Info("setup metrics...", "otel", otel, "port", metricsPort, "collector", otelCollector, "creds", transportCreds)
@@ -82,23 +72,29 @@ func setupMetrics(logger logr.Logger, kubeClient kubernetes.Interface) (*metrics
 }
 
 func main() {
+	// application flags
+	flagset := flag.NewFlagSet("application", flag.ExitOnError)
+	flagset.StringVar(&otel, "otelConfig", "prometheus", "Set this flag to 'grpc', to enable exporting metrics to an Opentelemetry Collector. The default collector is set to \"prometheus\"")
+	flagset.StringVar(&otelCollector, "otelCollector", "opentelemetrycollector.kyverno.svc.cluster.local", "Set this flag to the OpenTelemetry Collector Service Address. Kyverno will try to connect to this on the metrics port.")
+	flagset.StringVar(&transportCreds, "transportCreds", "", "Set this flag to the CA secret containing the certificate which is used by our Opentelemetry Metrics Client. If empty string is set, means an insecure connection will be used")
+	flagset.StringVar(&metricsPort, "metricsPort", "8000", "Expose prometheus metrics at the given port, default to 8000.")
+	flagset.BoolVar(&disableMetricsExport, "disableMetrics", false, "Set this flag to 'true' to disable metrics.")
 	// config
 	appConfig := internal.NewConfiguration(
 		internal.WithProfiling(),
 		internal.WithTracing(),
 		internal.WithKubeconfig(),
+		internal.WithFlagSets(flagset),
 	)
 	// parse flags
-	parseFlags(appConfig)
+	internal.ParseFlags(appConfig)
 	// setup logger
-	logger := internal.SetupLogger()
-	// setup maxprocs
-	undo := internal.SetupMaxProcs(logger)
-	defer undo()
 	// show version
-	internal.ShowVersion(logger)
 	// start profiling
-	internal.SetupProfiling(logger)
+	// setup signals
+	// setup maxprocs
+	ctx, logger, sdown := internal.Setup()
+	defer sdown()
 	// create raw client
 	rawClient := internal.CreateKubernetesClient(logger)
 	// setup signals
@@ -128,7 +124,7 @@ func main() {
 	secretLister := kubeKyvernoInformer.Core().V1().Secrets().Lister()
 	// start informers and wait for cache sync
 	// we need to call start again because we potentially registered new informers
-	if !internal.StartInformersAndWaitForCacheSync(signalCtx, kubeKyvernoInformer) {
+	if !internal.StartInformersAndWaitForCacheSync(ctx, kubeKyvernoInformer) {
 		os.Exit(1)
 	}
 	server := NewServer(
@@ -142,7 +138,7 @@ func main() {
 		},
 	)
 	// start webhooks server
-	server.Run(signalCtx.Done())
+	server.Run(ctx.Done())
 	// wait for termination signal
-	<-signalCtx.Done()
+	<-ctx.Done()
 }

cmd/initContainer/main.go

@@ -6,7 +6,6 @@ package main
 import (
 	"context"
 	"encoding/json"
-	"flag"
 	"os"
 	"sync"
 	"time"
@@ -34,46 +33,29 @@ const (
 	convertGenerateRequest  string = "ConvertGenerateRequest"
 )
 
-func parseFlags(config internal.Configuration) {
-	internal.InitFlags(config)
-	flag.Parse()
-}
-
 func main() {
 	// config
 	appConfig := internal.NewConfiguration(
 		internal.WithKubeconfig(),
 	)
 	// parse flags
-	parseFlags(appConfig)
+	internal.ParseFlags(appConfig)
 	// setup logger
-	logger := internal.SetupLogger()
-	// setup maxprocs
-	undo := internal.SetupMaxProcs(logger)
-	defer undo()
 	// show version
-	internal.ShowVersion(logger)
+	// start profiling
-	// os signal handler
+	// setup signals
-	signalCtx, signalCancel := internal.SetupSignals(logger)
+	// setup maxprocs
-	defer signalCancel()
+	ctx, logger, sdown := internal.Setup()
-
+	defer sdown()
+	// create clients
 	kubeClient := internal.CreateKubernetesClient(logger)
 	dynamicClient := internal.CreateDynamicClient(logger)
 	kyvernoClient := internal.CreateKyvernoClient(logger)
-
+	client, err := dclient.NewClient(ctx, dynamicClient, kubeClient, 15*time.Minute)
-	// DYNAMIC CLIENT
-	// - client for all registered resources
-	client, err := dclient.NewClient(
-		signalCtx,
-		dynamicClient,
-		kubeClient,
-		15*time.Minute,
-	)
 	if err != nil {
 		logger.Error(err, "Failed to create client")
 		os.Exit(1)
 	}
-
 	// Exit for unsupported version of kubernetes cluster
 	if !utils.HigherThanKubernetesVersion(kubeClient.Discovery(), logging.GlobalLogger(), 1, 16, 0) {
 		os.Exit(1)
@@ -86,8 +68,8 @@ func main() {
 	}
 
 	go func() {
-		defer signalCancel()
+		defer sdown()
-		<-signalCtx.Done()
+		<-ctx.Done()
 	}()
 
 	done := make(chan struct{})
@@ -113,19 +95,19 @@ func main() {
 			}
 		}
 
-		if err = acquireLeader(signalCtx, kubeClient); err != nil {
+		if err = acquireLeader(ctx, kubeClient); err != nil {
 			logging.V(2).Info("Failed to create lease 'kyvernopre-lock'")
 			os.Exit(1)
 		}
 
 		// use pipeline to pass request to cleanup resources
-		in := gen(done, signalCtx.Done(), requests...)
+		in := gen(done, ctx.Done(), requests...)
 		// process requests
 		// processing routine count : 2
-		p1 := process(client, kyvernoClient, done, signalCtx.Done(), in)
+		p1 := process(client, kyvernoClient, done, ctx.Done(), in)
-		p2 := process(client, kyvernoClient, done, signalCtx.Done(), in)
+		p2 := process(client, kyvernoClient, done, ctx.Done(), in)
 		// merge results from processing routines
-		for err := range merge(done, signalCtx.Done(), p1, p2) {
+		for err := range merge(done, ctx.Done(), p1, p2) {
 			if err != nil {
 				failure = true
 				logging.Error(err, "failed to cleanup resource")
@@ -155,7 +137,7 @@ func main() {
 		os.Exit(1)
 	}
 
-	le.Run(signalCtx)
+	le.Run(ctx)
 }
 
 func acquireLeader(ctx context.Context, kubeClient kubernetes.Interface) error {

cmd/internal/config.go

@@ -1,9 +1,12 @@
 package internal
 
+import "flag"
+
 type Configuration interface {
 	UsesTracing() bool
 	UsesProfiling() bool
 	UsesKubeconfig() bool
+	FlagSets() []*flag.FlagSet
 }
 
 func NewConfiguration(options ...ConfigurationOption) Configuration {
@@ -34,10 +37,17 @@ func WithKubeconfig() ConfigurationOption {
 	}
 }
 
+func WithFlagSets(flagsets ...*flag.FlagSet) ConfigurationOption {
+	return func(c *configuration) {
+		c.flagSets = append(c.flagSets, flagsets...)
+	}
+}
+
 type configuration struct {
 	usesTracing    bool
 	usesProfiling  bool
 	usesKubeconfig bool
+	flagSets       []*flag.FlagSet
 }
 
 func (c *configuration) UsesTracing() bool {
@@ -51,3 +61,7 @@ func (c *configuration) UsesProfiling() bool {
 func (c *configuration) UsesKubeconfig() bool {
 	return c.usesKubeconfig
 }
+
+func (c *configuration) FlagSets() []*flag.FlagSet {
+	return c.flagSets
+}

cmd/internal/flag.go

@@ -64,4 +64,14 @@ func InitFlags(config Configuration) {
 	if config.UsesKubeconfig() {
 		initKubeconfigFlags()
 	}
+	for _, flagset := range config.FlagSets() {
+		flagset.VisitAll(func(f *flag.Flag) {
+			flag.CommandLine.Var(f.Value, f.Name, f.Usage)
+		})
+	}
+}
+
+func ParseFlags(config Configuration) {
+	InitFlags(config)
+	flag.Parse()
 }

cmd/internal/setup.go

@@ -0,0 +1,25 @@
+package internal
+
+import (
+	"context"
+
+	"github.com/go-logr/logr"
+)
+
+func shutdown(logger logr.Logger, sdowns ...context.CancelFunc) context.CancelFunc {
+	return func() {
+		for i := range sdowns {
+			logger.Info("shuting down...")
+			defer sdowns[i]()
+		}
+	}
+}
+
+func Setup() (context.Context, logr.Logger, context.CancelFunc) {
+	logger := SetupLogger()
+	ShowVersion(logger)
+	sdownMaxProcs := SetupMaxProcs(logger)
+	SetupProfiling(logger)
+	ctx, sdownSignals := SetupSignals(logger)
+	return ctx, logger, shutdown(logger.WithName("shutdown"), sdownMaxProcs, sdownSignals)
+}