Merge pull request #10970 from vikas-goel/prepare-volume

Copy the content from the underlying image into the newly created volume

libpod/runtime_ctr.go

@@ -47,6 +47,32 @@ func (r *Runtime) NewContainer(ctx context.Context, rSpec *spec.Spec, options ..
 	return r.newContainer(ctx, rSpec, options...)
 }
 
+func (r *Runtime) PrepareVolumeOnCreateContainer(ctx context.Context, ctr *Container) error {
+	// Copy the content from the underlying image into the newly created
+	// volume if configured to do so.
+	if !r.config.Containers.PrepareVolumeOnCreate {
+		return nil
+	}
+
+	defer func() {
+		if err := ctr.cleanupStorage(); err != nil {
+			logrus.Errorf("error cleaning up container storage %s: %v", ctr.ID(), err)
+		}
+	}()
+
+	mountPoint, err := ctr.mountStorage()
+	if err == nil {
+		// Finish up mountStorage
+		ctr.state.Mounted = true
+		ctr.state.Mountpoint = mountPoint
+		if err = ctr.save(); err != nil {
+			logrus.Errorf("Error saving container %s state: %v", ctr.ID(), err)
+		}
+	}
+
+	return err
+}
+
 // RestoreContainer re-creates a container from an imported checkpoint
 func (r *Runtime) RestoreContainer(ctx context.Context, rSpec *spec.Spec, config *ContainerConfig) (*Container, error) {
 	r.lock.Lock()

pkg/specgen/generate/container_create.go

@@ -153,7 +153,15 @@ func MakeContainer(ctx context.Context, rt *libpod.Runtime, s *specgen.SpecGener
 	if err != nil {
 		return nil, err
 	}
-	return rt.NewContainer(ctx, runtimeSpec, options...)
+
+	ctr, err := rt.NewContainer(ctx, runtimeSpec, options...)
+	if err != nil {
+		return ctr, err
+	}
+
+	// Copy the content from the underlying image into the newly created
+	// volume if configured to do so.
+	return ctr, rt.PrepareVolumeOnCreateContainer(ctx, ctr)
 }
 
 func extractCDIDevices(s *specgen.SpecGenerator) []libpod.CtrCreateOption {

test/e2e/container_create_volume_test.go

@@ -0,0 +1,127 @@
+package integration
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	. "github.com/containers/podman/v3/test/utils"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	. "github.com/onsi/gomega/gexec"
+)
+
+func buildDataVolumeImage(pTest *PodmanTestIntegration, image, data, dest string) {
+	// Create a dummy file for data volume
+	dummyFile := filepath.Join(pTest.TempDir, data)
+	err := ioutil.WriteFile(dummyFile, []byte(data), 0644)
+	Expect(err).To(BeNil())
+
+	// Create a data volume container image but no CMD binary in it
+	containerFile := fmt.Sprintf(`FROM scratch
+CMD doesnotexist.sh
+ADD %s %s/
+VOLUME %s/`, data, dest, dest)
+	pTest.BuildImage(containerFile, image, "false")
+}
+
+func createContainersConfFile(pTest *PodmanTestIntegration) {
+	configPath := filepath.Join(pTest.TempDir, "containers.conf")
+	containersConf := []byte(fmt.Sprintf("[containers]\nprepare_volume_on_create = true\n"))
+	err := ioutil.WriteFile(configPath, containersConf, os.ModePerm)
+	Expect(err).To(BeNil())
+
+	// Set custom containers.conf file
+	os.Setenv("CONTAINERS_CONF", configPath)
+	if IsRemote() {
+		pTest.RestartRemoteService()
+	}
+}
+
+func checkDataVolumeContainer(pTest *PodmanTestIntegration, image, cont, dest, data string) {
+	create := pTest.Podman([]string{"create", "--name", cont, image})
+	create.WaitWithDefaultTimeout()
+	Expect(create).Should(Exit(0))
+
+	inspect := pTest.InspectContainer(cont)
+	Expect(len(inspect)).To(Equal(1))
+	Expect(len(inspect[0].Mounts)).To(Equal(1))
+	Expect(inspect[0].Mounts[0].Destination).To(Equal(dest))
+
+	mntName, mntSource := inspect[0].Mounts[0].Name, inspect[0].Mounts[0].Source
+
+	volList := pTest.Podman([]string{"volume", "list", "--quiet"})
+	volList.WaitWithDefaultTimeout()
+	Expect(volList).Should(Exit(0))
+	Expect(len(volList.OutputToStringArray())).To(Equal(1))
+	Expect(volList.OutputToStringArray()[0]).To(Equal(mntName))
+
+	// Check the mount source directory
+	files, err := ioutil.ReadDir(mntSource)
+	Expect(err).To(BeNil())
+
+	if data == "" {
+		Expect(len(files)).To(Equal(0))
+	} else {
+		Expect(len(files)).To(Equal(1))
+		Expect(files[0].Name()).To(Equal(data))
+	}
+}
+
+var _ = Describe("Podman create data volume", func() {
+	var (
+		tempdir    string
+		err        error
+		podmanTest *PodmanTestIntegration
+	)
+
+	BeforeEach(func() {
+		tempdir, err = CreateTempDirInTempDir()
+		if err != nil {
+			os.Exit(1)
+		}
+		podmanTest = PodmanTestCreate(tempdir)
+		podmanTest.Setup()
+		podmanTest.SeedImages()
+	})
+
+	AfterEach(func() {
+		podmanTest.Cleanup()
+		f := CurrentGinkgoTestDescription()
+		processTestResult(f)
+		os.Unsetenv("CONTAINERS_CONF")
+	})
+
+	It("podman create with volume data copy turned off", func() {
+		imgName, volData, volDest := "dataimg", "dummy", "/test"
+
+		buildDataVolumeImage(podmanTest, imgName, volData, volDest)
+
+		// Create a container with the default containers.conf and
+		// check that the volume is not copied from the image.
+		checkDataVolumeContainer(podmanTest, imgName, "ctr-nocopy", volDest, "")
+	})
+
+	It("podman create with volume data copy turned on", func() {
+		imgName, volData, volDest := "dataimg", "dummy", "/test"
+
+		buildDataVolumeImage(podmanTest, imgName, volData, volDest)
+
+		// Create a container with the custom containers.conf and
+		// check that the volume is copied from the image.
+		createContainersConfFile(podmanTest)
+
+		checkDataVolumeContainer(podmanTest, imgName, "ctr-copy", volDest, volData)
+	})
+
+	It("podman run with volume data copy turned on", func() {
+		// Create a container with the custom containers.conf and
+		// check that the container is run successfully
+		createContainersConfFile(podmanTest)
+
+		session := podmanTest.Podman([]string{"run", "--rm", ALPINE, "echo"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+	})
+})