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>

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)
+}

docs/source/markdown/podman-volume-export.1.md

@@ -35,4 +35,4 @@ $ podman volume export myvol --output myvol.tar
 ```
 
 ## SEE ALSO
-podman-volume(1)
+podman-volume(1), podman-volume-import(1)

docs/source/markdown/podman-volume-import.1.md

@@ -0,0 +1,35 @@
+% podman-volume-import(1)
+
+## NAME
+podman\-volume\-import - Import tarball contents into a podman volume
+
+## SYNOPSIS
+**podman volume import** *volume* [*source*]
+
+## DESCRIPTION
+
+**podman volume import** imports the contents of a tarball into the podman volume's mount point.
+**podman volume import** can consume piped input when using `-` as source path.
+
+Note: Following command is not supported by podman-remote.
+
+**podman volume import VOLUME [SOURCE]**
+
+#### **--help**
+
+Print usage statement
+
+## EXAMPLES
+
+```
+$ gunzip -c hellow.tar.gz | podman volume import myvol -
+```
+```
+$ podman volume import myvol test.tar
+```
+```
+$ podman volume export myvol | podman volume import oldmyvol -
+```
+
+## SEE ALSO
+podman-volume(1), podman-volume-export(1)

docs/source/markdown/podman-volume.1.md

@@ -16,6 +16,7 @@ podman volume is a set of subcommands that manage volumes.
 | create  | [podman-volume-create(1)](podman-volume-create.1.md)   | Create a new volume.                                                           |
 | exists  | [podman-volume-exists(1)](podman-volume-exists.1.md)   | Check if the given volume exists.                                              |
 | export  | [podman-volume-export(1)](podman-volume-export.1.md)   | Exports volume to external tar.                                                |
+| import  | [podman-volume-import(1)](podman-volume-import.1.md)   | Import tarball contents into a podman volume.                                  |
 | inspect | [podman-volume-inspect(1)](podman-volume-inspect.1.md) | Get detailed information on one or more volumes.                               |
 | ls      | [podman-volume-ls(1)](podman-volume-ls.1.md)           | List all the available volumes.                                                |
 | prune   | [podman-volume-prune(1)](podman-volume-prune.1.md)     | Remove all unused volumes.                                                     |

docs/source/volume.rst

@@ -6,6 +6,8 @@ Volume
 
 :doc:`export <markdown/podman-volume-export.1>` Exports volume to external tar
 
+:doc:`import <markdown/podman-volume-import.1>` Import tarball contents into a podman volume
+
 :doc:`inspect <markdown/podman-volume-inspect.1>` Display detailed information on one or more volumes
 
 :doc:`ls <markdown/podman-volume-ls.1>` List volumes

test/e2e/volume_create_test.go

@@ -79,6 +79,50 @@ var _ = Describe("Podman volume create", func() {
 		Expect(check.OutputToString()).To(ContainSubstring("hello"))
 	})
 
+	It("podman create and import volume", func() {
+		if podmanTest.RemoteTest {
+			Skip("Volume export check does not work with a remote client")
+		}
+
+		session := podmanTest.Podman([]string{"volume", "create", "my_vol"})
+		session.WaitWithDefaultTimeout()
+		volName := session.OutputToString()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"run", "--volume", volName + ":/data", ALPINE, "sh", "-c", "echo hello >> " + "/data/test"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"volume", "export", volName, "--output=hello.tar"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"volume", "create", "my_vol2"})
+		session.WaitWithDefaultTimeout()
+		volName = session.OutputToString()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"volume", "import", "my_vol2", "hello.tar"})
+		session.WaitWithDefaultTimeout()
+		volName = session.OutputToString()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"run", "--volume", "my_vol2:/data", ALPINE, "cat", "/data/test"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.OutputToString()).To(ContainSubstring("hello"))
+	})
+
+	It("podman import volume should fail", func() {
+		// try import on volume or source which does not exists
+		if podmanTest.RemoteTest {
+			Skip("Volume export check does not work with a remote client")
+		}
+
+		session := podmanTest.Podman([]string{"volume", "import", "notfound", "notfound.tar"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).To(ExitWithError())
+	})
+
 	It("podman create volume with bad volume option", func() {
 		session := podmanTest.Podman([]string{"volume", "create", "--opt", "badOpt=bad"})
 		session.WaitWithDefaultTimeout()

test/system/160-volumes.bats

@@ -186,6 +186,22 @@ EOF
 }
 
 
+# Podman volume import test
+@test "podman volume import test" {
+    skip_if_remote "volumes import is not applicable on podman-remote"
+    run_podman volume create my_vol
+    run_podman run --rm -v my_vol:/data $IMAGE sh -c "echo hello >> /data/test"
+    run_podman volume create my_vol2
+    run_podman volume export my_vol --output=hello.tar
+    # we want to use `run_podman volume export my_vol` but run_podman is wrapping EOF
+    cat hello.tar | run_podman volume import my_vol2 -
+    run_podman run --rm -v my_vol2:/data $IMAGE sh -c "cat /data/test"
+    is "$output" "hello" "output from second container"
+    run_podman volume rm my_vol
+    run_podman volume rm my_vol2
+}
+
+
 # Confirm that container sees the correct id
 @test "podman volume with --userns=keep-id" {
     is_rootless || skip "only meaningful when run rootless"