Always pull images by default

The behaviour prior to this patch caused some confusion for
users since they expected a behaviour like Swarm / Kubernetes
which always pulls images by default, even if cached. I've tested
the change and it is working as expected. By default images are
always pulled upon deployment.

To revert to the prior behaviour, simply add to faasd up:
--pull-policy=IfNotPresent

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

cmd/provider.go

@@ -19,13 +19,25 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var providerCmd = &cobra.Command{
+func makeProviderCmd() *cobra.Command {
+	var command = &cobra.Command{
 		Use:   "provider",
 		Short: "Run the faasd-provider",
-	RunE:  runProvider,
+	}
-}
 
-func runProvider(_ *cobra.Command, _ []string) error {
+	command.Flags().String("pull-policy", "Always", `Set to "Always" to force a pull of images upon deployment, or "IfNotPresent" to try to use a cached image.`)
+
+	command.RunE = func(_ *cobra.Command, _ []string) error {
+
+		pullPolicy, flagErr := command.Flags().GetString("pull-policy")
+		if flagErr != nil {
+			return flagErr
+		}
+
+		alwaysPull := false
+		if pullPolicy == "Always" {
+			alwaysPull = true
+		}
 
 		config, providerConfig, err := config.ReadFromEnv(types.OsEnv{})
 		if err != nil {
@@ -72,11 +84,11 @@ func runProvider(_ *cobra.Command, _ []string) error {
 		bootstrapHandlers := types.FaaSHandlers{
 			FunctionProxy:        proxy.NewHandlerFunc(*config, invokeResolver),
 			DeleteHandler:        handlers.MakeDeleteHandler(client, cni),
-		DeployHandler:        handlers.MakeDeployHandler(client, cni, userSecretPath),
+			DeployHandler:        handlers.MakeDeployHandler(client, cni, userSecretPath, alwaysPull),
 			FunctionReader:       handlers.MakeReadHandler(client),
 			ReplicaReader:        handlers.MakeReplicaReaderHandler(client),
 			ReplicaUpdater:       handlers.MakeReplicaUpdateHandler(client, cni),
-		UpdateHandler:        handlers.MakeUpdateHandler(client, cni, userSecretPath),
+			UpdateHandler:        handlers.MakeUpdateHandler(client, cni, userSecretPath, alwaysPull),
 			HealthHandler:        func(w http.ResponseWriter, r *http.Request) {},
 			InfoHandler:          handlers.MakeInfoHandler(Version, GitCommit),
 			ListNamespaceHandler: listNamespaces(),
@@ -93,8 +105,10 @@ func runProvider(_ *cobra.Command, _ []string) error {
 
 		log.Printf("Listening on TCP port: %d\n", *config.TCPPort)
 		bootstrap.Serve(&bootstrapHandlers, config)
-
 		return nil
+	}
+
+	return command
 }
 
 func listNamespaces() func(w http.ResponseWriter, r *http.Request) {

cmd/root.go

@@ -14,7 +14,7 @@ func init() {
 	rootCommand.AddCommand(versionCmd)
 	rootCommand.AddCommand(upCmd)
 	rootCommand.AddCommand(installCmd)
-	rootCommand.AddCommand(providerCmd)
+	rootCommand.AddCommand(makeProviderCmd())
 	rootCommand.AddCommand(collectCmd)
 }
 

cmd/up.go

@@ -14,8 +14,8 @@ import (
 
 	"github.com/pkg/errors"
 
-	"github.com/openfaas/faasd/pkg"
 	"github.com/alexellis/k3sup/pkg/env"
+	"github.com/openfaas/faasd/pkg"
 	"github.com/sethvargo/go-password/password"
 	"github.com/spf13/cobra"
 )
@@ -116,6 +116,7 @@ func runUp(_ *cobra.Command, _ []string) error {
 			log.Println(fileErr)
 			return
 		}
+
 		host := ""
 		lines := strings.Split(string(fileData), "\n")
 		for _, line := range lines {

pkg/provider/handlers/deploy.go

@@ -23,7 +23,7 @@ import (
 	"github.com/pkg/errors"
 )
 
-func MakeDeployHandler(client *containerd.Client, cni gocni.CNI, secretMountPath string) func(w http.ResponseWriter, r *http.Request) {
+func MakeDeployHandler(client *containerd.Client, cni gocni.CNI, secretMountPath string, alwaysPull bool) func(w http.ResponseWriter, r *http.Request) {
 
 	return func(w http.ResponseWriter, r *http.Request) {
 
@@ -54,7 +54,7 @@ func MakeDeployHandler(client *containerd.Client, cni gocni.CNI, secretMountPath
 		name := req.Service
 		ctx := namespaces.WithNamespace(context.Background(), FunctionNamespace)
 
-		deployErr := deploy(ctx, req, client, cni, secretMountPath)
+		deployErr := deploy(ctx, req, client, cni, secretMountPath, alwaysPull)
 		if deployErr != nil {
 			log.Printf("[Deploy] error deploying %s, error: %s\n", name, deployErr)
 			http.Error(w, deployErr.Error(), http.StatusBadRequest)
@@ -63,7 +63,7 @@ func MakeDeployHandler(client *containerd.Client, cni gocni.CNI, secretMountPath
 	}
 }
 
-func deploy(ctx context.Context, req types.FunctionDeployment, client *containerd.Client, cni gocni.CNI, secretMountPath string) error {
+func deploy(ctx context.Context, req types.FunctionDeployment, client *containerd.Client, cni gocni.CNI, secretMountPath string, alwaysPull bool) error {
 	r, err := reference.ParseNormalizedNamed(req.Image)
 	if err != nil {
 		return err
@@ -75,7 +75,7 @@ func deploy(ctx context.Context, req types.FunctionDeployment, client *container
 		snapshotter = val
 	}
 
-	image, err := service.PrepareImage(ctx, client, imgRef, snapshotter)
+	image, err := service.PrepareImage(ctx, client, imgRef, snapshotter, alwaysPull)
 	if err != nil {
 		return errors.Wrapf(err, "unable to pull image %s", imgRef)
 	}

pkg/provider/handlers/update.go

@@ -8,15 +8,15 @@ import (
 	"log"
 	"net/http"
 
-	"github.com/openfaas/faasd/pkg/cninetwork"
-	"github.com/openfaas/faasd/pkg/service"
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/namespaces"
 	gocni "github.com/containerd/go-cni"
 	"github.com/openfaas/faas-provider/types"
+	"github.com/openfaas/faasd/pkg/cninetwork"
+	"github.com/openfaas/faasd/pkg/service"
 )
 
-func MakeUpdateHandler(client *containerd.Client, cni gocni.CNI, secretMountPath string) func(w http.ResponseWriter, r *http.Request) {
+func MakeUpdateHandler(client *containerd.Client, cni gocni.CNI, secretMountPath string, alwaysPull bool) func(w http.ResponseWriter, r *http.Request) {
 
 	return func(w http.ResponseWriter, r *http.Request) {
 
@@ -68,7 +68,7 @@ func MakeUpdateHandler(client *containerd.Client, cni gocni.CNI, secretMountPath
 			return
 		}
 
-		deployErr := deploy(ctx, req, client, cni, secretMountPath)
+		deployErr := deploy(ctx, req, client, cni, secretMountPath, alwaysPull)
 		if deployErr != nil {
 			log.Printf("[Update] error deploying %s, error: %s\n", name, deployErr)
 			http.Error(w, deployErr.Error(), http.StatusBadRequest)

pkg/service/service.go

@@ -122,11 +122,12 @@ func getResolver(ctx context.Context, configFile *configfile.ConfigFile) (remote
 	return docker.NewResolver(opts), nil
 }
 
-func PrepareImage(ctx context.Context, client *containerd.Client, imageName, snapshotter string) (containerd.Image, error) {
+func PrepareImage(ctx context.Context, client *containerd.Client, imageName, snapshotter string, pullAlways bool) (containerd.Image, error) {
 	var (
 		empty    containerd.Image
 		resolver remotes.Resolver
 	)
+
 	if _, stErr := os.Stat(filepath.Join(dockerConfigDir, config.ConfigFileName)); stErr == nil {
 		configFile, err := config.Load(dockerConfigDir)
 		if err != nil {
@@ -140,22 +141,29 @@ func PrepareImage(ctx context.Context, client *containerd.Client, imageName, sna
 		return empty, stErr
 	}
 
-	image, err := client.GetImage(ctx, imageName)
+	var image containerd.Image
+	if pullAlways {
+		img, err := pullImage(ctx, client, resolver, imageName)
+		if err != nil {
+			return empty, err
+		}
+
+		image = img
+	} else {
+
+		img, err := client.GetImage(ctx, imageName)
 		if err != nil {
 			if !errdefs.IsNotFound(err) {
 				return empty, err
 			}
-		rOpts := []containerd.RemoteOpt{
+			img, err := pullImage(ctx, client, resolver, imageName)
-			containerd.WithPullUnpack,
-		}
-		if resolver != nil {
-			rOpts = append(rOpts, containerd.WithResolver(resolver))
-		}
-		img, err := client.Pull(ctx, imageName, rOpts...)
 			if err != nil {
-			return empty, fmt.Errorf("cannot pull: %s", err)
+				return empty, err
 			}
 			image = img
+		} else {
+			image = img
+		}
 	}
 
 	unpacked, err := image.IsUnpacked(ctx, snapshotter)
@@ -171,3 +179,21 @@ func PrepareImage(ctx context.Context, client *containerd.Client, imageName, sna
 
 	return image, nil
 }
+
+func pullImage(ctx context.Context, client *containerd.Client, resolver remotes.Resolver, imageName string) (containerd.Image, error) {
+
+	var empty containerd.Image
+
+	rOpts := []containerd.RemoteOpt{
+		containerd.WithPullUnpack,
+	}
+	if resolver != nil {
+		rOpts = append(rOpts, containerd.WithResolver(resolver))
+	}
+	img, err := client.Pull(ctx, imageName, rOpts...)
+	if err != nil {
+		return empty, fmt.Errorf("cannot pull: %s", err)
+	}
+
+	return img, nil
+}

pkg/supervisor.go

@@ -8,13 +8,13 @@ import (
 	"os"
 	"path"
 
-	"github.com/openfaas/faasd/pkg/cninetwork"
-	"github.com/openfaas/faasd/pkg/service"
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/cio"
 	"github.com/containerd/containerd/containers"
 	"github.com/containerd/containerd/oci"
 	gocni "github.com/containerd/go-cni"
+	"github.com/openfaas/faasd/pkg/cninetwork"
+	"github.com/openfaas/faasd/pkg/service"
 
 	"github.com/containerd/containerd/namespaces"
 	"github.com/opencontainers/runtime-spec/specs-go"
@@ -25,6 +25,7 @@ const (
 	workingDirectoryPermission = 0644
 	// faasdNamespace is the containerd namespace services are created
 	faasdNamespace         = "default"
+	faasServicesPullAlways = false
 )
 
 type Service struct {
@@ -88,7 +89,7 @@ func (s *Supervisor) Start(svcs []Service) error {
 	for _, svc := range svcs {
 		fmt.Printf("Preparing: %s with image: %s\n", svc.Name, svc.Image)
 
-		img, err := service.PrepareImage(ctx, s.client, svc.Image, defaultSnapshotter)
+		img, err := service.PrepareImage(ctx, s.client, svc.Image, defaultSnapshotter, faasServicesPullAlways)
 		if err != nil {
 			return err
 		}