Clear snapshot when container doesn't exist

This clears up a scenario where a container can be deleted but
its snapshot is not.

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

README.md

@@ -86,17 +86,17 @@ go build
 
 ```sh
 # For x86_64
-sudo curl -fSLs "https://github.com/alexellis/faasd/releases/download/0.2.4/faasd" \
+sudo curl -fSLs "https://github.com/alexellis/faasd/releases/download/0.2.5/faasd" \
     -o "/usr/local/bin/faasd" \
     && sudo chmod a+x "/usr/local/bin/faasd"
 
 # armhf
-sudo curl -fSLs "https://github.com/alexellis/faasd/releases/download/0.2.4/faasd-armhf" \
+sudo curl -fSLs "https://github.com/alexellis/faasd/releases/download/0.2.5/faasd-armhf" \
     -o "/usr/local/bin/faasd" \
     && sudo chmod a+x "/usr/local/bin/faasd"
 
 # arm64
-sudo curl -fSLs "https://github.com/alexellis/faasd/releases/download/0.2.4/faasd-arm64" \
+sudo curl -fSLs "https://github.com/alexellis/faasd/releases/download/0.2.5/faasd-arm64" \
     -o "/usr/local/bin/faasd" \
     && sudo chmod a+x "/usr/local/bin/faasd"
 ```

pkg/service/service.go

@@ -0,0 +1,117 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"sync"
+	"time"
+
+	"github.com/containerd/containerd"
+	"github.com/containerd/containerd/errdefs"
+	"golang.org/x/sys/unix"
+)
+
+// Remove removes a container
+func Remove(ctx context.Context, client *containerd.Client, name string) error {
+
+	container, containerErr := client.LoadContainer(ctx, name)
+
+	if containerErr == nil {
+		found := true
+		t, err := container.Task(ctx, nil)
+		if err != nil {
+			if errdefs.IsNotFound(err) {
+				found = false
+			} else {
+				return fmt.Errorf("unable to get task %s: ", err)
+			}
+		}
+
+		if found {
+			status, _ := t.Status(ctx)
+			fmt.Printf("Status of %s is: %s\n", name, status.Status)
+
+			log.Printf("Need to kill %s\n", name)
+			err := killTask(ctx, t)
+			if err != nil {
+				return fmt.Errorf("error killing task %s, %s, %s", container.ID(), name, err)
+			}
+		}
+
+		err = container.Delete(ctx, containerd.WithSnapshotCleanup)
+		if err != nil {
+			return fmt.Errorf("error deleting container %s, %s, %s", container.ID(), name, err)
+		}
+	} else {
+		service := client.SnapshotService("")
+		key := name + "snapshot"
+		if _, err := client.SnapshotService("").Stat(ctx, key); err == nil {
+			service.Remove(ctx, key)
+		}
+	}
+	return nil
+}
+
+// From Stellar
+func killTask(ctx context.Context, task containerd.Task) error {
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+	var err error
+	go func() {
+		defer wg.Done()
+		if task != nil {
+			wait, err := task.Wait(ctx)
+			if err != nil {
+				err = fmt.Errorf("error waiting on task: %s", err)
+				return
+			}
+			if err := task.Kill(ctx, unix.SIGTERM, containerd.WithKillAll); err != nil {
+				log.Printf("error killing container task: %s", err)
+			}
+			select {
+			case <-wait:
+				task.Delete(ctx)
+				return
+			case <-time.After(5 * time.Second):
+				if err := task.Kill(ctx, unix.SIGKILL, containerd.WithKillAll); err != nil {
+					log.Printf("error force killing container task: %s", err)
+				}
+				return
+			}
+		}
+	}()
+	wg.Wait()
+
+	return err
+}
+
+func PrepareImage(ctx context.Context, client *containerd.Client, imageName, snapshotter string) (containerd.Image, error) {
+
+	var empty containerd.Image
+	image, err := client.GetImage(ctx, imageName)
+	if err != nil {
+		if !errdefs.IsNotFound(err) {
+			return empty, err
+		}
+
+		img, err := client.Pull(ctx, imageName, containerd.WithPullUnpack)
+		if err != nil {
+			return empty, fmt.Errorf("cannot pull: %s", err)
+		}
+		image = img
+	}
+
+	unpacked, err := image.IsUnpacked(ctx, snapshotter)
+	if err != nil {
+		return empty, fmt.Errorf("cannot check if unpacked: %s", err)
+	}
+
+	if !unpacked {
+		if err := image.Unpack(ctx, snapshotter); err != nil {
+			return empty, fmt.Errorf("cannot unpack: %s", err)
+		}
+	}
+
+	return image, nil
+}

pkg/supervisor.go

@@ -8,15 +8,12 @@ import (
 	"os"
 	"os/exec"
 	"path"
-	"sync"
-	"time"
 
+	"github.com/alexellis/faasd/pkg/service"
 	"github.com/alexellis/faasd/pkg/weave"
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/cio"
 	"github.com/containerd/containerd/containers"
-	"github.com/containerd/containerd/errdefs"
-	"golang.org/x/sys/unix"
 
 	"github.com/containerd/containerd/namespaces"
 	"github.com/containerd/containerd/oci"
@@ -48,7 +45,7 @@ func (s *Supervisor) Remove(svcs []Service) error {
 	ctx := namespaces.WithNamespace(context.Background(), "default")
 
 	for _, svc := range svcs {
-		err := removeContainer(ctx, s.client, svc.Name)
+		err := service.Remove(ctx, s.client, svc.Name)
 		if err != nil {
 			return err
 		}
@@ -75,7 +72,7 @@ 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 := prepareImage(ctx, s.client, svc.Image)
+		img, err := service.PrepareImage(ctx, s.client, svc.Image, defaultSnapshotter)
 		if err != nil {
 			return err
 		}
@@ -87,13 +84,13 @@ func (s *Supervisor) Start(svcs []Service) error {
 	for _, svc := range svcs {
 		fmt.Printf("Reconciling: %s\n", svc.Name)
 
-		image := images[svc.Name]
-
-		containerErr := removeContainer(ctx, s.client, svc.Name)
+		containerErr := service.Remove(ctx, s.client, svc.Name)
 		if containerErr != nil {
 			return containerErr
 		}
 
+		image := images[svc.Name]
+
 		mounts := []specs.Mount{}
 		if len(svc.Mounts) > 0 {
 			for _, mnt := range svc.Mounts {
@@ -199,37 +196,6 @@ func (s *Supervisor) Start(svcs []Service) error {
 	return nil
 }
 
-func prepareImage(ctx context.Context, client *containerd.Client, imageName string) (containerd.Image, error) {
-	snapshotter := defaultSnapshotter
-
-	var empty containerd.Image
-	image, err := client.GetImage(ctx, imageName)
-	if err != nil {
-		if !errdefs.IsNotFound(err) {
-			return empty, err
-		}
-
-		img, err := client.Pull(ctx, imageName, containerd.WithPullUnpack)
-		if err != nil {
-			return empty, fmt.Errorf("cannot pull: %s", err)
-		}
-		image = img
-	}
-
-	unpacked, err := image.IsUnpacked(ctx, snapshotter)
-	if err != nil {
-		return empty, fmt.Errorf("cannot check if unpacked: %s", err)
-	}
-
-	if !unpacked {
-		if err := image.Unpack(ctx, snapshotter); err != nil {
-			return empty, fmt.Errorf("cannot unpack: %s", err)
-		}
-	}
-
-	return image, nil
-}
-
 func getIP(containerID string, taskPID uint32) string {
 	// https://github.com/weaveworks/weave/blob/master/net/netdev.go
 
@@ -274,70 +240,3 @@ func withOCIArgs(args []string) oci.SpecOpts {
 	}
 
 }
-
-// From Stellar
-func killTask(ctx context.Context, task containerd.Task) error {
-	wg := &sync.WaitGroup{}
-	wg.Add(1)
-	var err error
-	go func() {
-		defer wg.Done()
-		if task != nil {
-			wait, err := task.Wait(ctx)
-			if err != nil {
-				err = fmt.Errorf("error waiting on task: %s", err)
-				return
-			}
-			if err := task.Kill(ctx, unix.SIGTERM, containerd.WithKillAll); err != nil {
-				log.Printf("error killing container task: %s", err)
-			}
-			select {
-			case <-wait:
-				task.Delete(ctx)
-				return
-			case <-time.After(5 * time.Second):
-				if err := task.Kill(ctx, unix.SIGKILL, containerd.WithKillAll); err != nil {
-					log.Printf("error force killing container task: %s", err)
-				}
-				return
-			}
-		}
-	}()
-	wg.Wait()
-
-	return err
-}
-
-func removeContainer(ctx context.Context, client *containerd.Client, name string) error {
-
-	container, containerErr := client.LoadContainer(ctx, name)
-
-	if containerErr == nil {
-		found := true
-		t, err := container.Task(ctx, nil)
-		if err != nil {
-			if errdefs.IsNotFound(err) {
-				found = false
-			} else {
-				return fmt.Errorf("unable to get task %s: ", err)
-			}
-		}
-
-		if found {
-			status, _ := t.Status(ctx)
-			fmt.Printf("Status of %s is: %s\n", name, status.Status)
-
-			log.Printf("Need to kill %s\n", name)
-			err := killTask(ctx, t)
-			if err != nil {
-				return fmt.Errorf("error killing task %s, %s, %s", container.ID(), name, err)
-			}
-		}
-
-		err = container.Delete(ctx, containerd.WithSnapshotCleanup)
-		if err != nil {
-			return fmt.Errorf("error deleting container %s, %s, %s", container.ID(), name, err)
-		}
-	}
-	return nil
-}