Rewrite backend for remote 'volume inspect'

We need to use the new Inspect() endpoint instead of trying to
JSON the actual volume structs. Currently, the output seems
completely nonsensical; it seems like we're JSONing the struct
for the Varlink connection itself? This should restore sanity and
match the format of remote and local inspect on volumes.

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

API.md

@@ -107,6 +107,8 @@ in the [API.md](https://github.com/containers/libpod/blob/master/API.md) file in
 
 [func InspectPod(name: string) string](#InspectPod)
 
+[func InspectVolume(name: string) string](#InspectVolume)
+
 [func KillContainer(name: string, signal: int) string](#KillContainer)
 
 [func KillPod(name: string, signal: int) string](#KillPod)
@@ -804,6 +806,12 @@ method InspectPod(name: [string](https://godoc.org/builtin#string)) [string](htt
 InspectPod takes the name or ID of an image and returns a string representation of data associated with the
 pod.  You must serialize the string into JSON to use it further.  A [PodNotFound](#PodNotFound) error will
 be returned if the pod cannot be found.
+### <a name="InspectVolume"></a>func InspectVolume
+<div style="background-color: #E8E8E8; padding: 15px; margin: 10px; border-radius: 10px;">
+
+method InspectVolume(name: [string](https://godoc.org/builtin#string)) [string](https://godoc.org/builtin#string)</div>
+InspectVolume inspects a single volume. Returns inspect JSON in the form of a
+string.
 ### <a name="KillContainer"></a>func KillContainer
 <div style="background-color: #E8E8E8; padding: 15px; margin: 10px; border-radius: 10px;">
 

cmd/podman/varlink/io.podman.varlink

@@ -1268,6 +1268,10 @@ method VolumeRemove(options: VolumeRemoveOpts) -> (successes: []string, failures
 # GetVolumes gets slice of the volumes on a remote host
 method GetVolumes(args: []string, all: bool) -> (volumes: []Volume)
 
+# InspectVolume inspects a single volume. Returns inspect JSON in the form of a
+# string.
+method InspectVolume(name: string) -> (volume: string)
+
 # VolumesPrune removes unused volumes on the host
 method VolumesPrune() -> (prunedNames: []string, prunedErrors: []string)
 

pkg/adapter/runtime_remote.go

@@ -659,12 +659,39 @@ func (r *LocalRuntime) Push(ctx context.Context, srcName, destination, manifestM
 }
 
 // InspectVolumes returns a slice of volumes based on an arg list or --all
-func (r *LocalRuntime) InspectVolumes(ctx context.Context, c *cliconfig.VolumeInspectValues) ([]*Volume, error) {
-	reply, err := iopodman.GetVolumes().Call(r.Conn, c.InputArgs, c.All)
-	if err != nil {
-		return nil, err
+func (r *LocalRuntime) InspectVolumes(ctx context.Context, c *cliconfig.VolumeInspectValues) ([]*libpod.InspectVolumeData, error) {
+	var (
+		inspectData []*libpod.InspectVolumeData
+		volumes     []string
+	)
+
+	if c.All {
+		allVolumes, err := r.Volumes(ctx)
+		if err != nil {
+			return nil, err
+		}
+		for _, vol := range allVolumes {
+			volumes = append(volumes, vol.Name())
+		}
+	} else {
+		for _, arg := range c.InputArgs {
+			volumes = append(volumes, arg)
+		}
 	}
-	return varlinkVolumeToVolume(r, reply), nil
+
+	for _, vol := range volumes {
+		jsonString, err := iopodman.InspectVolume().Call(r.Conn, vol)
+		if err != nil {
+			return nil, err
+		}
+		inspectJSON := new(libpod.InspectVolumeData)
+		if err := json.Unmarshal([]byte(jsonString), inspectJSON); err != nil {
+			return nil, errors.Wrapf(err, "error unmarshalling inspect JSON for volume %s", vol)
+		}
+		inspectData = append(inspectData, inspectJSON)
+	}
+
+	return inspectData, nil
 }
 
 // Volumes returns a slice of adapter.volumes based on information about libpod

pkg/varlinkapi/volumes.go

@@ -3,6 +3,8 @@
 package varlinkapi
 
 import (
+	"encoding/json"
+
 	"github.com/containers/libpod/cmd/podman/shared"
 	"github.com/containers/libpod/cmd/podman/varlink"
 	"github.com/containers/libpod/libpod"
@@ -80,6 +82,23 @@ func (i *LibpodAPI) GetVolumes(call iopodman.VarlinkCall, args []string, all boo
 	return call.ReplyGetVolumes(volumes)
 }
 
+// InspectVolume inspects a single volume, returning its JSON as a string.
+func (i *LibpodAPI) InspectVolume(call iopodman.VarlinkCall, name string) error {
+	vol, err := i.Runtime.LookupVolume(name)
+	if err != nil {
+		return call.ReplyErrorOccurred(err.Error())
+	}
+	inspectOut, err := vol.Inspect()
+	if err != nil {
+		return call.ReplyErrorOccurred(err.Error())
+	}
+	inspectJSON, err := json.Marshal(inspectOut)
+	if err != nil {
+		return call.ReplyErrorOccurred(err.Error())
+	}
+	return call.ReplyInspectVolume(string(inspectJSON))
+}
+
 // VolumesPrune removes unused images via a varlink call
 func (i *LibpodAPI) VolumesPrune(call iopodman.VarlinkCall) error {
 	var errs []string