Add NewContainer and Delete container support

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

client.go

@@ -2,11 +2,23 @@ package containerd
 
 import (
 	"context"
+	"encoding/json"
 	"io/ioutil"
 	"log"
 	"time"
 
 	"github.com/containerd/containerd/api/services/containers"
+	contentapi "github.com/containerd/containerd/api/services/content"
+	snapshotapi "github.com/containerd/containerd/api/services/snapshot"
+	"github.com/containerd/containerd/content"
+	"github.com/containerd/containerd/images"
+	contentservice "github.com/containerd/containerd/services/content"
+	snapshotservice "github.com/containerd/containerd/services/snapshot"
+	"github.com/containerd/containerd/snapshot"
+	protobuf "github.com/gogo/protobuf/types"
+	"github.com/opencontainers/image-spec/identity"
+	"github.com/opencontainers/image-spec/specs-go/v1"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/grpclog"
@@ -51,6 +63,88 @@ func (c *Client) Containers(ctx context.Context) ([]*Container, error) {
 	return out, nil
 }
 
+type NewContainerOpts func(ctx context.Context, client *Client, c *containers.Container) error
+
+// NewContainerWithLables adds the provided labels to the container
+func NewContainerWithLables(labels map[string]string) NewContainerOpts {
+	return func(_ context.Context, _ *Client, c *containers.Container) error {
+		c.Labels = labels
+		return nil
+	}
+}
+
+// NewContainerWithExistingRootFS uses an existing root filesystem for the container
+func NewContainerWithExistingRootFS(id string) NewContainerOpts {
+	return func(ctx context.Context, client *Client, c *containers.Container) error {
+		// check that the snapshot exists, if not, fail on creation
+		if _, err := client.snapshotter().Mounts(ctx, id); err != nil {
+			return err
+		}
+		c.RootFS = id
+		return nil
+	}
+}
+
+// NewContainerWithNewRootFS allocates a new snapshot to be used by the container as the
+// root filesystem in read-write mode
+func NewContainerWithNewRootFS(id string, image v1.Descriptor) NewContainerOpts {
+	return func(ctx context.Context, client *Client, c *containers.Container) error {
+		diffIDs, err := images.RootFS(ctx, client.content(), image)
+		if err != nil {
+			return err
+		}
+		if _, err := client.snapshotter().Prepare(ctx, id, identity.ChainID(diffIDs).String()); err != nil {
+			return err
+		}
+		c.RootFS = id
+		return nil
+	}
+}
+
+// NewContainerWithNewReadonlyRootFS allocates a new snapshot to be used by the container as the
+// root filesystem in read-only mode
+func NewContainerWithNewReadonlyRootFS(id string, image v1.Descriptor) NewContainerOpts {
+	return func(ctx context.Context, client *Client, c *containers.Container) error {
+		diffIDs, err := images.RootFS(ctx, client.content(), image)
+		if err != nil {
+			return err
+		}
+		if _, err := client.snapshotter().View(ctx, id, identity.ChainID(diffIDs).String()); err != nil {
+			return err
+		}
+		c.RootFS = id
+		return nil
+	}
+}
+
+// NewContainer will create a new container in container with the provided id
+// the id must be unique within the namespace
+func (c *Client) NewContainer(ctx context.Context, id string, spec *specs.Spec, opts ...NewContainerOpts) (*Container, error) {
+	data, err := json.Marshal(spec)
+	if err != nil {
+		return nil, err
+	}
+	container := containers.Container{
+		ID: id,
+		Spec: &protobuf.Any{
+			TypeUrl: specs.Version,
+			Value:   data,
+		},
+	}
+	for _, o := range opts {
+		if err := o(ctx, c, &container); err != nil {
+			return nil, err
+		}
+	}
+	r, err := c.containers().Create(ctx, &containers.CreateContainerRequest{
+		Container: container,
+	})
+	if err != nil {
+		return nil, err
+	}
+	return containerFromProto(c, r.Container), nil
+}
+
 // Close closes the clients connection to containerd
 func (c *Client) Close() error {
 	return c.conn.Close()
@@ -59,3 +153,11 @@ func (c *Client) Close() error {
 func (c *Client) containers() containers.ContainersClient {
 	return containers.NewContainersClient(c.conn)
 }
+
+func (c *Client) content() content.Store {
+	return contentservice.NewStoreFromClient(contentapi.NewContentClient(c.conn))
+}
+
+func (c *Client) snapshotter() snapshot.Snapshotter {
+	return snapshotservice.NewSnapshotterFromClient(snapshotapi.NewSnapshotClient(c.conn))
+}