volumes: Add volume import to allow importing contents on tar into volume

Following feature makes sure that users can load contents of external
tarball into the podman volumes.

Signed-off-by: flouthoc <flouthoc.git@gmail.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/cmd/podman/volumes/import.go b/cmd/podman/volumes/import.go
new file mode 100644
index 000000000..441bd0fe4
--- /dev/null
+++ b/cmd/podman/volumes/import.go
@@ -0,0 +1,97 @@
+package volumes
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/containers/podman/v3/cmd/podman/common"
+	"github.com/containers/podman/v3/cmd/podman/inspect"
+	"github.com/containers/podman/v3/cmd/podman/parse"
+	"github.com/containers/podman/v3/cmd/podman/registry"
+	"github.com/containers/podman/v3/pkg/domain/entities"
+	"github.com/containers/podman/v3/utils"
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+)
+
+var (
+	importDescription = `Imports contents into a podman volume from specified tarball (.tar, .tar.gz, .tgz, .bzip, .tar.xz, .txz).`
+	importCommand     = &cobra.Command{
+		Annotations:       map[string]string{registry.EngineMode: registry.ABIMode},
+		Use:               "import VOLUME [SOURCE]",
+		Short:             "Import a tarball contents into a podman volume",
+		Long:              importDescription,
+		RunE:              importVol,
+		Args:              cobra.ExactArgs(2),
+		ValidArgsFunction: common.AutocompleteVolumes,
+		Example: `podman volume import my_vol /home/user/import.tar
+  cat ctr.tar | podman import volume my_vol -`,
+	}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: importCommand,
+		Parent:  volumeCmd,
+	})
+}
+
+func importVol(cmd *cobra.Command, args []string) error {
+	var inspectOpts entities.InspectOptions
+	var tarFile *os.File
+	containerEngine := registry.ContainerEngine()
+	ctx := registry.Context()
+	// create a slice of volumes since inspect expects slice as arg
+	volumes := []string{args[0]}
+	tarPath := args[1]
+
+	if tarPath != "-" {
+		err := parse.ValidateFileName(tarPath)
+		if err != nil {
+			return err
+		}
+
+		// open tar file
+		tarFile, err = os.Open(tarPath)
+		if err != nil {
+			return err
+		}
+	} else {
+		tarFile = os.Stdin
+	}
+
+	inspectOpts.Type = inspect.VolumeType
+	volumeData, _, err := containerEngine.VolumeInspect(ctx, volumes, inspectOpts)
+	if err != nil {
+		return err
+	}
+	if len(volumeData) < 1 {
+		return errors.New("no volume data found")
+	}
+	mountPoint := volumeData[0].VolumeConfigResponse.Mountpoint
+	driver := volumeData[0].VolumeConfigResponse.Driver
+	volumeOptions := volumeData[0].VolumeConfigResponse.Options
+	volumeMountStatus, err := containerEngine.VolumeMounted(ctx, args[0])
+	if err != nil {
+		return err
+	}
+	if mountPoint == "" {
+		return errors.New("volume is not mounted anywhere on host")
+	}
+	// Check if volume is using external plugin and export only if volume is mounted
+	if driver != "" && driver != "local" {
+		if !volumeMountStatus.Value {
+			return fmt.Errorf("volume is using a driver %s and volume is not mounted on %s", driver, mountPoint)
+		}
+	}
+	// Check if volume is using `local` driver and has mount options type other than tmpfs
+	if driver == "local" {
+		if mountOptionType, ok := volumeOptions["type"]; ok {
+			if mountOptionType != "tmpfs" && !volumeMountStatus.Value {
+				return fmt.Errorf("volume is using a driver %s and volume is not mounted on %s", driver, mountPoint)
+			}
+		}
+	}
+	// dont care if volume is mounted or not we are gonna import everything to mountPoint
+	return utils.UntarToFileSystem(mountPoint, tarFile, nil)
+}