From 77cbcba0906d70736f20d6f1513f1f3b3d054af3 Mon Sep 17 00:00:00 2001
From: biecho <diego.a.meyer@gmail.com>
Date: Sun, 30 Oct 2022 12:15:39 -0600
Subject: [PATCH] When pulling images check for stale cached images

---
 ctriface/iface.go                             | 82 +++++++++++++------
 ctriface/iface_test.go                        |  4 +-
 .../self-hosted-kind/scripts/setup-runner.sh  |  3 +
 taps/tapManager.go                            |  1 -
 4 files changed, 60 insertions(+), 30 deletions(-)

diff --git a/ctriface/iface.go b/ctriface/iface.go
index 6cef27890..0f2bdd6ff 100644
--- a/ctriface/iface.go
+++ b/ctriface/iface.go
@@ -50,10 +50,10 @@ import (
 	_ "google.golang.org/grpc/codes"  //tmp
 	_ "google.golang.org/grpc/status" //tmp
 
+	"github.com/go-multierror/multierror"
 	"github.com/vhive-serverless/vhive/memory/manager"
 	"github.com/vhive-serverless/vhive/metrics"
 	"github.com/vhive-serverless/vhive/misc"
-	"github.com/go-multierror/multierror"
 
 	_ "github.com/davecgh/go-spew/spew" //tmp
 )
@@ -314,42 +314,70 @@ func getImageURL(image string) string {
 
 func (o *Orchestrator) getImage(ctx context.Context, imageName string) (*containerd.Image, error) {
 	image, found := o.cachedImages[imageName]
-	if !found {
-		var err error
-		log.Debug(fmt.Sprintf("Pulling image %s", imageName))
-
-		imageURL := getImageURL(imageName)
-		local, _ := isLocalDomain(imageURL)
-		if local {
-			// Pull local image using HTTP
-			resolver := docker.NewResolver(docker.ResolverOptions{
-				Client: http.DefaultClient,
-				Hosts: docker.ConfigureDefaultRegistries(
-					docker.WithPlainHTTP(docker.MatchAllHosts),
-				),
-			})
-			image, err = o.client.Pull(ctx, imageURL,
-				containerd.WithPullUnpack,
-				containerd.WithPullSnapshotter(o.snapshotter),
-				containerd.WithResolver(resolver),
-			)
-		} else {
-			// Pull remote image
-			image, err = o.client.Pull(ctx, imageURL,
-				containerd.WithPullUnpack,
-				containerd.WithPullSnapshotter(o.snapshotter),
-			)
-		}
+
+	imageUrl := getImageURL(imageName)
+	if !found || imageIsOutdated(image, imageUrl) {
+		image, err := o.pullImage(ctx, imageUrl)
 
 		if err != nil {
 			return &image, err
 		}
 		o.cachedImages[imageName] = image
+		return &image, nil
 	}
 
 	return &image, nil
 }
 
+func imageIsOutdated(cachedImage containerd.Image, imageUrl string) bool {
+	remoteImageDigest, err := remoteImageDigest(imageUrl)
+	return err == nil && cachedImage.Target().Digest.String() != remoteImageDigest
+}
+
+func remoteImageDigest(imageUrl string) (string, error) {
+	cmd := fmt.Sprintf("skopeo inspect docker://%s | jq -r '.Digest'", imageUrl)
+
+	start := time.Now()
+	out, err := exec.Command("bash", "-c", cmd).Output()
+	elapsed := time.Since(start)
+	log.Printf("Remote digest fetching took %s", elapsed)
+
+	return string(out), err
+}
+
+func (o *Orchestrator) pullImage(ctx context.Context, imageUrl string) (containerd.Image, error) {
+	log.Debugf("Pulling image %s\n", imageUrl)
+
+	local, _ := isLocalDomain(imageUrl)
+
+	if local {
+		return o.pullLocalImage(ctx, imageUrl)
+	}
+	return o.pullRemoteImage(ctx, imageUrl)
+}
+
+func (o *Orchestrator) pullRemoteImage(ctx context.Context, imageUrl string) (containerd.Image, error) {
+	return o.client.Pull(ctx, imageUrl,
+		containerd.WithPullUnpack,
+		containerd.WithPullSnapshotter(o.snapshotter),
+	)
+}
+
+// Pull local image using HTTP
+func (o *Orchestrator) pullLocalImage(ctx context.Context, imageUrl string) (containerd.Image, error) {
+	resolver := docker.NewResolver(docker.ResolverOptions{
+		Client: http.DefaultClient,
+		Hosts: docker.ConfigureDefaultRegistries(
+			docker.WithPlainHTTP(docker.MatchAllHosts),
+		),
+	})
+	return o.client.Pull(ctx, imageUrl,
+		containerd.WithPullUnpack,
+		containerd.WithPullSnapshotter(o.snapshotter),
+		containerd.WithResolver(resolver),
+	)
+}
+
 func getK8sDNS() []string {
 	//using googleDNS as a backup
 	dnsIPs := []string{"8.8.8.8"}
diff --git a/ctriface/iface_test.go b/ctriface/iface_test.go
index cda2e97a0..9a39e8d58 100644
--- a/ctriface/iface_test.go
+++ b/ctriface/iface_test.go
@@ -1,6 +1,6 @@
 // MIT License
 //
-// Copyright (c) 2020 Dmitrii Ustiugov, Plamen Petrov and EASE lab
+// # Copyright (c) 2020 Dmitrii Ustiugov, Plamen Petrov and EASE lab
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
@@ -41,7 +41,7 @@ var (
 	isUPFEnabled = flag.Bool("upf", false, "Set UPF enabled")
 	isLazyMode   = flag.Bool("lazy", false, "Set lazy serving on or off")
 	//nolint:deadcode,unused,varcheck
-	isWithCache  = flag.Bool("withCache", false, "Do not drop the cache before measurements")
+	isWithCache = flag.Bool("withCache", false, "Do not drop the cache before measurements")
 )
 
 func TestPauseSnapResume(t *testing.T) {
diff --git a/scripts/self-hosted-kind/scripts/setup-runner.sh b/scripts/self-hosted-kind/scripts/setup-runner.sh
index 7805dad02..26dfe5ca7 100644
--- a/scripts/self-hosted-kind/scripts/setup-runner.sh
+++ b/scripts/self-hosted-kind/scripts/setup-runner.sh
@@ -24,6 +24,9 @@
 
 set -e
 
+# Needed for 'skopeo'
+echo "deb http://mirrors.kernel.org/ubuntu kinetic main universe" | sudo tee -a /etc/apt/sources.list
+
 # Install base- and setup-dependencies
 apt-get update
 apt-get install --yes \
diff --git a/taps/tapManager.go b/taps/tapManager.go
index d079d1e79..646cf412d 100644
--- a/taps/tapManager.go
+++ b/taps/tapManager.go
@@ -126,7 +126,6 @@ func setupForwardRules(tapName, hostIface string) error {
 		}
 	}
 
-
 	conn := nftables.Conn{}
 
 	// 1. nft add table ip filter