Initial

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

pkg/supervisor.go

@@ -0,0 +1,67 @@
+package pkg
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/containerd/containerd"
+	"github.com/containerd/containerd/namespaces"
+)
+
+type Supervisor struct {
+	client *containerd.Client
+}
+
+func NewSupervisor(sock string) (*Supervisor, error) {
+	client, err := containerd.New(sock)
+	if err != nil {
+		panic(err)
+	}
+
+	return &Supervisor{
+		client: client,
+	}, nil
+}
+
+func (s *Supervisor) Close() {
+	defer s.client.Close()
+}
+
+func (s *Supervisor) Start(svcs []Service) error {
+	for _, svc := range svcs {
+		fmt.Printf("Preparing: %s", svc.Name)
+
+		fmt.Printf("Pulling: %s\n", svc.Image)
+		bytesOut, err := pullImage(s.client, svc.Image)
+		if err != nil {
+			return err
+		}
+		fmt.Printf("Pull done for: %s, %d bytes\n", svc.Image, bytesOut)
+	}
+
+	return nil
+}
+
+func pullImage(client *containerd.Client, image string) (int64, error) {
+	ctx := namespaces.WithNamespace(context.Background(), "default")
+
+	pulled, err := client.Pull(ctx, image, containerd.WithPullUnpack)
+
+	if err != nil {
+		return 0, err
+	}
+	bytesOut, _ := pulled.Size(ctx)
+	return bytesOut, nil
+}
+
+type Service struct {
+	Image  string
+	Env    []string
+	Name   string
+	Mounts []Mount
+}
+
+type Mount struct {
+	Src  string
+	Dest string
+}