Add preliminary libpod image API

Signed-off-by: Matthew Heon <mheon@redhat.com>

libpod/runtime.go

@@ -1,29 +1,18 @@
 package libpod
 
 import (
+	"github.com/containers/storage"
 	"github.com/kubernetes-incubator/cri-o/libpod/ctr"
 	"github.com/kubernetes-incubator/cri-o/libpod/pod"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 )
 
-// ContainerFilter is a function to determine whether a container is included
-// in command output. Containers to be outputted are tested using the function.
-// A true return will include the container, a false return will exclude it.
-type ContainerFilter func(*ctr.Container) bool
-
-// PodFilter is a function to determine whether a pod is included in command
-// output. Pods to be outputted are tested using the function. A true return
-// will include the pod, a false return will exclude it.
-type PodFilter func(*pod.Pod) bool
+// Runtime API
 
 // A RuntimeOption is a functional option which alters the Runtime created by
 // NewRuntime
 type RuntimeOption func(*Runtime) error
 
-// A CtrCreateOption is a functional option which alters the Container created
-// by NewContainer
-type CtrCreateOption func(*ctr.Container) error
-
 // Runtime is the core libpod runtime
 type Runtime struct {
 	// TODO populate
@@ -34,6 +23,17 @@ func NewRuntime(options ...RuntimeOption) (*Runtime, error) {
 	return nil, ctr.ErrNotImplemented
 }
 
+// Container API
+
+// A CtrCreateOption is a functional option which alters the Container created
+// by NewContainer
+type CtrCreateOption func(*ctr.Container) error
+
+// ContainerFilter is a function to determine whether a container is included
+// in command output. Containers to be outputted are tested using the function.
+// A true return will include the container, a false return will exclude it.
+type ContainerFilter func(*ctr.Container) bool
+
 // NewContainer creates a new container from a given OCI config
 func (r *Runtime) NewContainer(spec *spec.Spec, options ...CtrCreateOption) (*ctr.Container, error) {
 	return nil, ctr.ErrNotImplemented
@@ -65,6 +65,13 @@ func (r *Runtime) GetContainers(filters ...ContainerFilter) ([]*ctr.Container, e
 	return nil, ctr.ErrNotImplemented
 }
 
+// Pod API
+
+// PodFilter is a function to determine whether a pod is included in command
+// output. Pods to be outputted are tested using the function. A true return
+// will include the pod, a false return will exclude it.
+type PodFilter func(*pod.Pod) bool
+
 // NewPod makes a new, empty pod
 func (r *Runtime) NewPod() (*pod.Pod, error) {
 	return nil, ctr.ErrNotImplemented
@@ -97,4 +104,64 @@ func (r *Runtime) GetPods(filters ...PodFilter) ([]*pod.Pod, error) {
 	return nil, ctr.ErrNotImplemented
 }
 
-// TODO Add image API
+// Image API
+
+// ImageFilter is a function to determine whether an image is included in
+// command output. Images to be outputted are tested using the function. A true
+// return will include the image, a false return will exclude it.
+type ImageFilter func(*storage.Image) bool
+
+// PullImage pulls an image from configured registries
+// By default, only the latest tag (or a specific tag if requested) will be
+// pulled. If allTags is true, all tags for the requested image will be pulled.
+// Signature validation will be performed if the Runtime has been appropriately
+// configured
+func (r *Runtime) PullImage(image string, allTags bool) (*storage.Image, error) {
+	return nil, ctr.ErrNotImplemented
+}
+
+// PushImage pushes the given image to a location described by the given path
+func (r *Runtime) PushImage(image *storage.Image, destination string) error {
+	return ctr.ErrNotImplemented
+}
+
+// TagImage adds a tag to the given image
+func (r *Runtime) TagImage(image *storage.Image, tag string) error {
+	return ctr.ErrNotImplemented
+}
+
+// UntagImage removes a tag from the given image
+func (r *Runtime) UntagImage(image *storage.Image, tag string) error {
+	return ctr.ErrNotImplemented
+}
+
+// RemoveImage deletes an image from local storage
+// Images being used by running containers cannot be removed
+func (r *Runtime) RemoveImage(image *storage.Image) error {
+	return ctr.ErrNotImplemented
+}
+
+// GetImage retrieves an image matching the given name or hash from system
+// storage
+// If no matching image can be found, an error is returned
+func (r *Runtime) GetImage(image string) (*storage.Image, error) {
+	return nil, ctr.ErrNotImplemented
+}
+
+// GetImages retrieves all images present in storage
+// Filters can be provided which will determine which images are included in the
+// output. Multiple filters are handled by ANDing their output, so only images
+// matching all filters are included
+func (r *Runtime) GetImages(filter ...ImageFilter) ([]*storage.Image, error) {
+	return nil, ctr.ErrNotImplemented
+}
+
+// CommitContainer commits the changes between a container and its image,
+// creating a new image
+// If the container was not created from an image (for example,
+// WithRootFSFromPath will create a container from a directory on the system),
+// a new base image will be created from the contents of the container's
+// filesystem
+func (r *Runtime) CommitContainer(c *ctr.Container) (*storage.Image, error) {
+	return nil, ctr.ErrNotImplemented
+}