Add varlink support for prune

Add the ability to prune unused images using the varlink
API.

Signed-off-by: baude <bbaude@redhat.com>

API.md

@@ -57,6 +57,8 @@ in the [API.md](https://github.com/containers/libpod/blob/master/API.md) file in
 
 [func ImageExists(name: string) int](#ImageExists)
 
+[func ImagesPrune() []string](#ImagesPrune)
+
 [func ImportImage(source: string, reference: string, message: string, changes: []string) string](#ImportImage)
 
 [func InspectContainer(name: string) string](#InspectContainer)
@@ -543,6 +545,12 @@ $ varlink call -m unix:/run/podman/io.podman/io.podman.ImageExists '{"name": "im
   "exists": 1
 }
 ~~~
+### <a name="ImagesPrune"></a>func ImagesPrune
+<div style="background-color: #E8E8E8; padding: 15px; margin: 10px; border-radius: 10px;">
+
+method ImagesPrune() [[]string](#[]string)</div>
+ImagesPrune removes all unused images from the local store.  Upon successful pruning,
+the IDs of the removed images are returned.
 ### <a name="ImportImage"></a>func ImportImage
 <div style="background-color: #E8E8E8; padding: 15px; margin: 10px; border-radius: 10px;">
 

cmd/podman/images_prune.go

@@ -1,8 +1,8 @@
 package main
 
 import (
+	"fmt"
 	"github.com/containers/libpod/cmd/podman/libpodruntime"
-	"github.com/containers/libpod/cmd/podman/shared"
 	"github.com/pkg/errors"
 	"github.com/urfave/cli"
 )
@@ -30,5 +30,16 @@ func pruneImagesCmd(c *cli.Context) error {
 	}
 	defer runtime.Shutdown(false)
 
-	return shared.Prune(runtime.ImageRuntime())
+	pruneImages, err := runtime.ImageRuntime().GetPruneImages()
+	if err != nil {
+		return err
+	}
+
+	for _, i := range pruneImages {
+		if err := i.Remove(true); err != nil {
+			return errors.Wrapf(err, "failed to remove %s", i.ID())
+		}
+		fmt.Println(i.ID())
+	}
+	return nil
 }

cmd/podman/shared/prune.go

@@ -1,24 +0,0 @@
-package shared
-
-import (
-	"fmt"
-	"github.com/pkg/errors"
-
-	"github.com/containers/libpod/libpod/image"
-)
-
-// Prune removes all unnamed and unused images from the local store
-func Prune(ir *image.Runtime) error {
-	pruneImages, err := ir.GetPruneImages()
-	if err != nil {
-		return err
-	}
-
-	for _, i := range pruneImages {
-		if err := i.Remove(true); err != nil {
-			return errors.Wrapf(err, "failed to remove %s", i.ID())
-		}
-		fmt.Println(i.ID())
-	}
-	return nil
-}

cmd/podman/varlink/io.podman.varlink

@@ -1015,6 +1015,10 @@ method MountContainer(name: string) -> (path: string)
 # ~~~
 method  UnmountContainer(name: string, force: bool) -> ()
 
+# ImagesPrune removes all unused images from the local store.  Upon successful pruning,
+# the IDs of the removed images are returned.
+method ImagesPrune() -> (pruned: []string)
+
 # This function is not implemented yet.
 method ListContainerPorts(name: string) -> (notimplemented: NotImplemented)
 

pkg/varlinkapi/images.go

@@ -620,3 +620,21 @@ func (i *LibpodAPI) ContainerRunlabel(call iopodman.VarlinkCall, input iopodman.
 	}
 	return call.ReplyContainerRunlabel()
 }
+
+// ImagesPrune ....
+func (i *LibpodAPI) ImagesPrune(call iopodman.VarlinkCall) error {
+	var (
+		pruned []string
+	)
+	pruneImages, err := i.Runtime.ImageRuntime().GetPruneImages()
+	if err != nil {
+		return err
+	}
+	for _, i := range pruneImages {
+		if err := i.Remove(true); err != nil {
+			return call.ReplyErrorOccurred(err.Error())
+		}
+		pruned = append(pruned, i.ID())
+	}
+	return call.ReplyImagesPrune(pruned)
+}