podman: accept option --rootfs to use exploded images

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

Closes: #871
Approved by: mheon

6 files changed, 91 insertions, 39 deletions

diff --git a/libpod/container.go b/libpod/container.go
index 85b6fa3dd..26232e5c0 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -197,6 +197,8 @@ type ContainerConfig struct {
 	// Information on the image used for the root filesystem/
 	RootfsImageID   string `json:"rootfsImageID,omitempty"`
 	RootfsImageName string `json:"rootfsImageName,omitempty"`
+	// Rootfs to use for the container, this conflicts with RootfsImageID
+	Rootfs string `json:"rootfs,omitempty"`
 	// Whether to mount volumes specified in the image.
 	ImageVolumes bool `json:"imageVolumes"`
 	// Src path to be mounted on /dev/shm in container.
diff --git a/libpod/container_commit.go b/libpod/container_commit.go
index 2872012b8..929850cbe 100644
--- a/libpod/container_commit.go
+++ b/libpod/container_commit.go
@@ -34,6 +34,10 @@ func (c *Container) Commit(ctx context.Context, destImage string, options Contai
 		isEnvCleared, isLabelCleared, isExposeCleared, isVolumeCleared bool
 	)
 
+	if c.config.Rootfs != "" {
+		return nil, errors.Errorf("cannot commit a container that uses an exploded rootfs")
+	}
+
 	if !c.batched {
 		c.lock.Lock()
 		defer c.lock.Unlock()
diff --git a/libpod/container_inspect.go b/libpod/container_inspect.go
index c8bf1a8cd..0e37036ca 100644
--- a/libpod/container_inspect.go
+++ b/libpod/container_inspect.go
@@ -70,6 +70,7 @@ func (c *Container) getContainerInspectData(size bool, driverData *inspect.Data)
 		},
 		ImageID:         config.RootfsImageID,
 		ImageName:       config.RootfsImageName,
+		Rootfs:          config.Rootfs,
 		ResolvConfPath:  resolvPath,
 		HostnamePath:    hostnamePath,
 		HostsPath:       hostsPath,
diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index e25ffaa03..b3e474836 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -56,6 +56,10 @@ var (
 // mutable layer, and the rest is the RootFS: the set of immutable layers
 // that make up the image on which the container is based.
 func (c *Container) rootFsSize() (int64, error) {
+	if c.config.Rootfs != "" {
+		return 0, nil
+	}
+
 	container, err := c.runtime.store.Container(c.ID())
 	if err != nil {
 		return 0, err
@@ -93,6 +97,18 @@ func (c *Container) rootFsSize() (int64, error) {
 
 // rwSize Gets the size of the mutable top layer of the container.
 func (c *Container) rwSize() (int64, error) {
+	if c.config.Rootfs != "" {
+		var size int64
+		err := filepath.Walk(c.config.Rootfs, func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+			size += info.Size()
+			return nil
+		})
+		return size, err
+	}
+
 	container, err := c.runtime.store.Container(c.ID())
 	if err != nil {
 		return 0, err
@@ -205,7 +221,7 @@ func (c *Container) setupStorage(ctx context.Context) error {
 	}
 
 	// Need both an image ID and image name, plus a bool telling us whether to use the image configuration
-	if c.config.RootfsImageID == "" || c.config.RootfsImageName == "" {
+	if c.config.Rootfs == "" && (c.config.RootfsImageID == "" || c.config.RootfsImageName == "") {
 		return errors.Wrapf(ErrInvalidArg, "must provide image ID and image name to use an image")
 	}
 
@@ -691,9 +707,12 @@ func (c *Container) mountStorage() (err error) {
 		}
 	}
 
-	mountPoint, err := c.runtime.storageService.MountContainerImage(c.ID())
-	if err != nil {
-		return errors.Wrapf(err, "error mounting storage for container %s", c.ID())
+	mountPoint := c.config.Rootfs
+	if mountPoint == "" {
+		mountPoint, err = c.runtime.storageService.MountContainerImage(c.ID())
+		if err != nil {
+			return errors.Wrapf(err, "error mounting storage for container %s", c.ID())
+		}
 	}
 	c.state.Mounted = true
 	c.state.Mountpoint = mountPoint
@@ -796,6 +815,9 @@ func (c *Container) cleanupStorage() error {
 			}
 		}
 	}
+	if c.config.Rootfs != "" {
+		return nil
+	}
 
 	// Also unmount storage
 	if err := c.runtime.storageService.UnmountContainerImage(c.ID()); err != nil {
@@ -1154,7 +1176,7 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 		return nil, errors.Wrapf(err, "error setting up OCI Hooks")
 	}
 	// Bind builtin image volumes
-	if c.config.ImageVolumes {
+	if c.config.Rootfs == "" && c.config.ImageVolumes {
 		if err := c.addImageVolumes(ctx, &g); err != nil {
 			return nil, errors.Wrapf(err, "error mounting image volumes")
 		}
@@ -1235,8 +1257,10 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 		}
 	}
 
-	if err := idtools.MkdirAllAs(c.state.RealMountpoint, 0700, c.RootUID(), c.RootGID()); err != nil {
-		return nil, err
+	if c.config.Rootfs == "" {
+		if err := idtools.MkdirAllAs(c.state.RealMountpoint, 0700, c.RootUID(), c.RootGID()); err != nil {
+			return nil, err
+		}
 	}
 
 	g.SetRootPath(c.state.RealMountpoint)
diff --git a/libpod/options.go b/libpod/options.go
index 34bde3211..02bcb8628 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -2,6 +2,7 @@ package libpod
 
 import (
 	"net"
+	"os"
 	"path/filepath"
 	"regexp"
 	"syscall"
@@ -361,6 +362,9 @@ func WithRootFSFromImage(imageID string, imageName string, useImageVolumes bool)
 		if ctr.config.RootfsImageID != "" || ctr.config.RootfsImageName != "" {
 			return errors.Wrapf(ErrInvalidArg, "container already configured with root filesystem")
 		}
+		if ctr.config.Rootfs != "" {
+			return errors.Wrapf(ErrInvalidArg, "cannot set both an image ID and a rootfs for a container")
+		}
 
 		ctr.config.RootfsImageID = imageID
 		ctr.config.RootfsImageName = imageName
@@ -909,6 +913,23 @@ func WithCommand(command []string) CtrCreateOption {
 	}
 }
 
+// WithRootFS sets the rootfs for the container
+func WithRootFS(rootfs string) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+		if _, err := os.Stat(rootfs); err != nil {
+			return errors.Wrapf(err, "error checking path %q", rootfs)
+		}
+		if ctr.config.RootfsImageID != "" {
+			return errors.Wrapf(ErrInvalidArg, "cannot set both an image ID and a rootfs for a container")
+		}
+		ctr.config.Rootfs = rootfs
+		return nil
+	}
+}
+
 // Pod Creation Options
 
 // WithPodName sets the name of the pod.
diff --git a/libpod/storage.go b/libpod/storage.go
index c0391326c..c5581d53c 100644
--- a/libpod/storage.go
+++ b/libpod/storage.go
@@ -60,40 +60,40 @@ func (metadata *RuntimeContainerMetadata) SetMountLabel(mountLabel string) {
 // CreateContainerStorage creates the storage end of things.  We already have the container spec created
 // TO-DO We should be passing in an Image object in the future.
 func (r *storageService) CreateContainerStorage(ctx context.Context, systemContext *types.SystemContext, imageName, imageID, containerName, containerID, mountLabel string, options *storage.ContainerOptions) (ContainerInfo, error) {
-	var ref types.ImageReference
-	if imageName == "" && imageID == "" {
-		return ContainerInfo{}, ErrEmptyID
-	}
-	if containerName == "" {
-		return ContainerInfo{}, ErrEmptyID
-	}
-	// Check if we have the specified image.
-	ref, err := istorage.Transport.ParseStoreReference(r.store, imageID)
-	if err != nil {
-		return ContainerInfo{}, err
-	}
-	img, err := istorage.Transport.GetStoreImage(r.store, ref)
-	if err != nil {
-		return ContainerInfo{}, err
-	}
-	// Pull out a copy of the image's configuration.
-	image, err := ref.NewImage(ctx, systemContext)
-	if err != nil {
-		return ContainerInfo{}, err
-	}
-	defer image.Close()
+	var imageConfig *v1.Image
+	if imageName != "" {
+		var ref types.ImageReference
+		if containerName == "" {
+			return ContainerInfo{}, ErrEmptyID
+		}
+		// Check if we have the specified image.
+		ref, err := istorage.Transport.ParseStoreReference(r.store, imageID)
+		if err != nil {
+			return ContainerInfo{}, err
+		}
+		img, err := istorage.Transport.GetStoreImage(r.store, ref)
+		if err != nil {
+			return ContainerInfo{}, err
+		}
+		// Pull out a copy of the image's configuration.
+		image, err := ref.NewImage(ctx, systemContext)
+		if err != nil {
+			return ContainerInfo{}, err
+		}
+		defer image.Close()
 
-	// Get OCI configuration of image
-	imageConfig, err := image.OCIConfig(ctx)
-	if err != nil {
-		return ContainerInfo{}, err
-	}
+		// Get OCI configuration of image
+		imageConfig, err = image.OCIConfig(ctx)
+		if err != nil {
+			return ContainerInfo{}, err
+		}
 
-	// Update the image name and ID.
-	if imageName == "" && len(img.Names) > 0 {
-		imageName = img.Names[0]
+		// Update the image name and ID.
+		if imageName == "" && len(img.Names) > 0 {
+			imageName = img.Names[0]
+		}
+		imageID = img.ID
 	}
-	imageID = img.ID
 
 	// Build metadata to store with the container.
 	metadata := RuntimeContainerMetadata{
@@ -119,7 +119,7 @@ func (r *storageService) CreateContainerStorage(ctx context.Context, systemConte
 			},
 		}
 	}
-	container, err := r.store.CreateContainer(containerID, names, img.ID, "", string(mdata), options)
+	container, err := r.store.CreateContainer(containerID, names, imageID, "", string(mdata), options)
 	if err != nil {
 		logrus.Debugf("failed to create container %s(%s): %v", metadata.ContainerName, containerID, err)