Add NewContainer and Delete container support

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

container.go

@@ -1,21 +1,47 @@
 package containerd
 
-import "github.com/containerd/containerd/api/services/containers"
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/containerd/containerd/api/services/containers"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+)
 
 func containerFromProto(client *Client, c containers.Container) *Container {
 	return &Container{
 		client: client,
-		id:     c.ID,
+		c:      c,
 	}
 }
 
 type Container struct {
 	client *Client
 
-	id string
+	c containers.Container
 }
 
 // ID returns the container's unique id
 func (c *Container) ID() string {
-	return c.id
+	return c.c.ID
+}
+
+// Spec returns the current OCI specification for the container
+func (c *Container) Spec() (*specs.Spec, error) {
+	var s specs.Spec
+	if err := json.Unmarshal(c.c.Spec.Value, &s); err != nil {
+		return nil, err
+	}
+	return &s, nil
+}
+
+// Delete deletes an existing container
+// an error is returned if the container has running tasks
+func (c *Container) Delete(ctx context.Context) error {
+	// TODO: should the client be the one removing resources attached
+	// to the container at the moment before we have GC?
+	_, err := c.client.containers().Delete(ctx, &containers.DeleteContainerRequest{
+		ID: c.c.ID,
+	})
+	return err
 }