Merge pull request #6439 from nihar4276/metrics-adaptor-json-logging

JSON logging support for Karmada Metrics Adapter component

Author: karmada-bot

artifacts/deploy/karmada-metrics-adapter.yaml

@@ -46,6 +46,7 @@ spec:
             - --audit-log-maxbackup=0
             - --tls-min-version=VersionTLS13
             - --bind-address=$(POD_IP)
+            - --logging-format=json
           readinessProbe:
             httpGet:
               path: /readyz

cmd/metrics-adapter/app/metrics-adapter.go

@@ -22,9 +22,14 @@ import (
 
 	"github.com/spf13/cobra"
 	cliflag "k8s.io/component-base/cli/flag"
+	"k8s.io/component-base/logs"
+	logsv1 "k8s.io/component-base/logs/api/v1"
 	"k8s.io/component-base/term"
+	"k8s.io/klog/v2"
+	controllerruntime "sigs.k8s.io/controller-runtime"
 
 	"github.com/karmada-io/karmada/cmd/metrics-adapter/app/options"
+	"github.com/karmada-io/karmada/pkg/features"
 	"github.com/karmada-io/karmada/pkg/sharedcli"
 	"github.com/karmada-io/karmada/pkg/sharedcli/klogflag"
 	"github.com/karmada-io/karmada/pkg/util/names"
@@ -33,7 +38,17 @@ import (
 
 // NewMetricsAdapterCommand creates a *cobra.Command object with default parameters
 func NewMetricsAdapterCommand(ctx context.Context) *cobra.Command {
+	logConfig := logsv1.NewLoggingConfiguration()
+	fss := cliflag.NamedFlagSets{}
+
+	logsFlagSet := fss.FlagSet("logs")
+	logs.AddFlags(logsFlagSet, logs.SkipLoggingConfigurationFlags())
+	logsv1.AddFlags(logConfig, logsFlagSet)
+	klogflag.Add(logsFlagSet)
+
+	genericFlagSet := fss.FlagSet("generic")
 	opts := options.NewOptions()
+	opts.AddFlags(genericFlagSet)
 
 	cmd := &cobra.Command{
 		Use:  names.KarmadaMetricsAdapterComponentName,
@@ -50,6 +65,19 @@ func NewMetricsAdapterCommand(ctx context.Context) *cobra.Command {
 			}
 			return nil
 		},
+		PersistentPreRunE: func(_ *cobra.Command, _ []string) error {
+			if err := logsv1.ValidateAndApply(logConfig, features.FeatureGate); err != nil {
+				return err
+			}
+			logs.InitLogs()
+			// Starting from version 0.15.0, controller-runtime expects its consumers to set a logger through log.SetLogger.
+			// If SetLogger is not called within the first 30 seconds of a binaries lifetime, it will get
+			// set to a NullLogSink and report an error. Here's to silence the "log.SetLogger(...) was never called; logs will not be displayed" error
+			// by setting a logger through log.SetLogger.
+			// More info refer to: https://github.com/karmada-io/karmada/pull/4885.
+			controllerruntime.SetLogger(klog.Background())
+			return nil
+		},
 		Args: func(cmd *cobra.Command, args []string) error {
 			for _, arg := range args {
 				if len(arg) > 0 {
@@ -60,15 +88,6 @@ func NewMetricsAdapterCommand(ctx context.Context) *cobra.Command {
 		},
 	}
 
-	fss := cliflag.NamedFlagSets{}
-
-	genericFlagSet := fss.FlagSet("generic")
-	opts.AddFlags(genericFlagSet)
-
-	// Set klog flags
-	logsFlagSet := fss.FlagSet("logs")
-	klogflag.Add(logsFlagSet)
-
 	cmd.AddCommand(sharedcommand.NewCmdVersion(names.KarmadaMetricsAdapterComponentName))
 	cmd.Flags().AddFlagSet(genericFlagSet)
 	cmd.Flags().AddFlagSet(logsFlagSet)

cmd/metrics-adapter/main.go

@@ -20,22 +20,18 @@ import (
 	"os"
 
 	"k8s.io/component-base/cli"
+	"k8s.io/component-base/logs"
 	_ "k8s.io/component-base/logs/json/register" // for JSON log format registration
-	"k8s.io/klog/v2"
 	controllerruntime "sigs.k8s.io/controller-runtime"
 
 	"github.com/karmada-io/karmada/cmd/metrics-adapter/app"
 )
 
 func main() {
 	ctx := controllerruntime.SetupSignalHandler()
-	// Starting from version 0.15.0, controller-runtime expects its consumers to set a logger through log.SetLogger.
-	// If SetLogger is not called within the first 30 seconds of a binaries lifetime, it will get
-	// set to a NullLogSink and report an error. Here's to silence the "log.SetLogger(...) was never called; logs will not be displayed" error
-	// by setting a logger through log.SetLogger.
-	// More info refer to: https://github.com/karmada-io/karmada/pull/4885.
-	controllerruntime.SetLogger(klog.Background())
 	cmd := app.NewMetricsAdapterCommand(ctx)
-	code := cli.Run(cmd)
-	os.Exit(code)
+	exitCode := cli.Run(cmd)
+	// Ensure any buffered log entries are flushed
+	logs.FlushLogs()
+	os.Exit(exitCode)
 }