From 50eed0c5a27385730caec4a981049fd064bbddff Mon Sep 17 00:00:00 2001
From: Francesco Cheinasso <francesco.cheinasso@staff.aruba.it>
Date: Thu, 12 Oct 2023 19:29:18 +0200
Subject: [PATCH] Metric Agent: cache fix

---
 cmd/metric-agent/main.go | 66 ++++++++++++++++++++++++++++++++--------
 1 file changed, 54 insertions(+), 12 deletions(-)

diff --git a/cmd/metric-agent/main.go b/cmd/metric-agent/main.go
index 43f65b99eb..3d902ffc26 100644
--- a/cmd/metric-agent/main.go
+++ b/cmd/metric-agent/main.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package main is the entrypoint of the metric-agent.
 package main
 
 import (
@@ -19,14 +20,13 @@ import (
 	"flag"
 	"fmt"
 	"net/http"
+	"os"
 
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/selection"
-	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/client-go/kubernetes"
-	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/klog/v2"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/cache"
@@ -35,7 +35,6 @@ import (
 
 	"github.com/liqotech/liqo/pkg/consts"
 	"github.com/liqotech/liqo/pkg/remotemetrics"
-	clientutils "github.com/liqotech/liqo/pkg/utils/clients"
 	"github.com/liqotech/liqo/pkg/utils/mapper"
 	"github.com/liqotech/liqo/pkg/utils/restcfg"
 )
@@ -49,6 +48,8 @@ func main() {
 
 	keyPath := flag.String("key-path", "server.key", "Path to the key file")
 	certPath := flag.String("cert-path", "server.crt", "Path to the certificate file")
+	readTimeout := flag.Duration("read-timeout", 0, "Read timeout")
+	writeTimeout := flag.Duration("write-timeout", 0, "Write timeout")
 	port := flag.Int("port", 8443, "Port to listen on")
 
 	klog.InitFlags(nil)
@@ -61,18 +62,25 @@ func main() {
 	kcl := kubernetes.NewForConfigOrDie(config)
 
 	scheme := runtime.NewScheme()
-	_ = clientgoscheme.AddToScheme(scheme)
+	if err := corev1.AddToScheme(scheme); err != nil {
+		klog.Fatalf("error adding client-go scheme: %s", err)
+		os.Exit(1)
+	}
 
 	liqoMapper, err := (mapper.LiqoMapperProvider(scheme))(config, nil)
 	if err != nil {
 		klog.Fatalf("mapper: %s", err)
+		os.Exit(1)
 	}
 
 	podsLabelRequirement, err := labels.NewRequirement(consts.ManagedByLabelKey,
 		selection.Equals, []string{consts.ManagedByShadowPodValue})
-	utilruntime.Must(err)
+	if err != nil {
+		klog.Fatalf("error creating label requirement: %s", err)
+		os.Exit(1)
+	}
 
-	cacheOptions := &cache.Options{
+	podcache, err := cache.New(config, cache.Options{
 		Scheme: scheme,
 		Mapper: liqoMapper,
 		ByObject: map[client.Object]cache.ByObject{
@@ -80,23 +88,57 @@ func main() {
 				Label: labels.NewSelector().Add(*podsLabelRequirement),
 			},
 		},
+	})
+
+	go func() {
+		klog.Info("starting pod cache")
+		if err := podcache.Start(ctx); err != nil {
+			klog.Fatalf("error starting pod cache: %s", err)
+			os.Exit(1)
+		}
+	}()
+
+	klog.Info("waiting for pod cache sync")
+
+	if ok := podcache.WaitForCacheSync(ctx); !ok {
+		klog.Fatalf("error waiting for cache sync: %s", err)
+		os.Exit(1)
 	}
+
+	klog.Info("pod cache synced")
+
 	if err != nil {
-		klog.Fatalf("error creating cache: %s", err)
+		klog.Fatalf("error creating pod cache: %s", err)
+		os.Exit(1)
 	}
 
-	cl, err := clientutils.GetCachedClientWithConfig(ctx, scheme, config, cacheOptions)
+	cl, err := client.New(config, client.Options{
+		Cache: &client.CacheOptions{
+			Reader: podcache,
+		},
+	})
+
 	if err != nil {
-		klog.Fatal(err)
+		klog.Fatalf("error creating client: %s", err)
+		os.Exit(1)
 	}
 
 	router, err := remotemetrics.GetHTTPHandler(kcl.RESTClient(), cl)
 	if err != nil {
 		klog.Fatal(err)
+		os.Exit(1)
 	}
 
-	err = http.ListenAndServeTLS(fmt.Sprintf(":%d", *port), *certPath, *keyPath, router)
-	if err != nil {
-		klog.Fatal("ListenAndServe: ", err)
+	server := http.Server{
+		Addr:         fmt.Sprintf(":%d", *port),
+		Handler:      router,
+		ReadTimeout:  *readTimeout,
+		WriteTimeout: *writeTimeout,
+	}
+
+	klog.Infof("starting server on port %d", *port)
+	if err := server.ListenAndServeTLS(*certPath, *keyPath); err != nil {
+		klog.Fatal(err)
+		os.Exit(1)
 	}
 }