list the volumes to be deleted without forcing

cmd/podman/volumes/prune.go

@@ -49,7 +49,9 @@ func init() {
 
 func prune(cmd *cobra.Command, args []string) error {
 	var (
-		pruneOptions = entities.VolumePruneOptions{}
+		pruneOptions  = entities.VolumePruneOptions{}
+		listOptions   = entities.VolumeListOptions{}
+		unusedOptions = entities.VolumeListOptions{}
 	)
 	// Prompt for confirmation if --force is not set
 	force, err := cmd.Flags().GetBool("force")
@@ -58,7 +60,35 @@ func prune(cmd *cobra.Command, args []string) error {
 	}
 	if !force {
 		reader := bufio.NewReader(os.Stdin)
-		fmt.Println("WARNING! This will remove all volumes not used by at least one container.")
+		fmt.Println("WARNING! This will remove all volumes not used by at least one container. The following volumes will be removed:")
+		pruneOptions.Filters, err = filters.ParseFilterArgumentsIntoFilters(filter)
+		listOptions.Filter, err = filters.ParseFilterArgumentsIntoFilters(filter)
+		if err != nil {
+			return err
+		}
+		// filter all the unused (unbound) volumes
+		unusedOptions.Filter = make(map[string][]string, 1)
+		unusedOptions.Filter["unused"] = []string{"true"}
+		if err != nil {
+			return err
+		}
+		unusedVolumes, err := registry.ContainerEngine().VolumeList(context.Background(), unusedOptions)
+		if err != nil {
+			return err
+		}
+		// filter volumes based on user input
+		filteredVolumes, err := registry.ContainerEngine().VolumeList(context.Background(), listOptions)
+		if err != nil {
+			return err
+		}
+		finalVolumes := getUnion(unusedVolumes, filteredVolumes)
+		if len(finalVolumes) < 1 {
+			fmt.Println("No unused volumes found")
+			return nil
+		}
+		for _, fv := range finalVolumes {
+			fmt.Println(fv.Name)
+		}
 		fmt.Print("Are you sure you want to continue? [y/N] ")
 		answer, err := reader.ReadString('\n')
 		if err != nil {
@@ -68,13 +98,23 @@ func prune(cmd *cobra.Command, args []string) error {
 			return nil
 		}
 	}
-	pruneOptions.Filters, err = filters.ParseFilterArgumentsIntoFilters(filter)
-	if err != nil {
-		return err
-	}
 	responses, err := registry.ContainerEngine().VolumePrune(context.Background(), pruneOptions)
 	if err != nil {
 		return err
 	}
 	return utils.PrintVolumePruneResults(responses, false)
 }
+
+func getUnion(a, b []*entities.VolumeListReport) []*entities.VolumeListReport {
+	var intersection []*entities.VolumeListReport
+	hash := make(map[string]bool, len(a))
+	for _, aa := range a {
+		hash[aa.Name] = true
+	}
+	for _, bb := range b {
+		if hash[bb.Name] {
+			intersection = append(intersection, bb)
+		}
+	}
+	return intersection
+}

pkg/domain/filters/volumes.go

@@ -85,6 +85,31 @@ func GenerateVolumeFilters(filters url.Values) ([]libpod.VolumeFilter, error) {
 					}
 					return dangling
 				})
+			case "unused":
+				invert := false
+				unusedVal := val
+				switch strings.ToLower(unusedVal) {
+				case "true", "1":
+					// do nth
+				case "false", "0":
+					invert = true
+
+				default:
+					return nil, errors.Errorf("%q is not a valid value for the \"unused\" filter - must be true or false", unusedVal)
+				}
+				vf = append(vf, func(v *libpod.Volume) bool {
+					resp, err := v.VolumeInUse()
+					if err != nil || len(resp) > 0 {
+						if !invert {
+							return false
+						}
+						return true
+					}
+					if !invert {
+						return true
+					}
+					return false
+				})
 			default:
 				return nil, errors.Errorf("%q is in an invalid volume filter", filter)
 			}

test/e2e/volume_prune_test.go

@@ -54,6 +54,11 @@ var _ = Describe("Podman volume prune", func() {
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
 
+		session = podmanTest.Podman([]string{"volume", "prune"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(Equal(4))
+
 		session = podmanTest.Podman([]string{"volume", "ls"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))

test/runecho.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+for i in {1..9};
+do
+    echo "This is a new container pull ipbabble [" $i "]"
+done