Retool mount detection for tests

pkg/kubelet/volume/empty_dir/empty_dir.go

@@ -82,10 +82,10 @@ func (plugin *emptyDirPlugin) CanSupport(spec *api.Volume) bool {
 
 func (plugin *emptyDirPlugin) NewBuilder(spec *api.Volume, podRef *api.ObjectReference) (volume.Builder, error) {
 	// Inject real implementations here, test through the internal function.
-	return plugin.newBuilderInternal(spec, podRef, plugin.mounter, &realMediumer{})
+	return plugin.newBuilderInternal(spec, podRef, plugin.mounter, &realMountDetector{})
 }
 
-func (plugin *emptyDirPlugin) newBuilderInternal(spec *api.Volume, podRef *api.ObjectReference, mounter mount.Interface, mediumer mediumer) (volume.Builder, error) {
+func (plugin *emptyDirPlugin) newBuilderInternal(spec *api.Volume, podRef *api.ObjectReference, mounter mount.Interface, mountDetector mountDetector) (volume.Builder, error) {
 	if plugin.legacyMode {
 		// Legacy mode instances can be cleaned up but not created anew.
 		return nil, fmt.Errorf("legacy mode: can not create new instances")
@@ -95,41 +95,46 @@ func (plugin *emptyDirPlugin) newBuilderInternal(spec *api.Volume, podRef *api.O
 		medium = spec.EmptyDir.Medium
 	}
 	return &emptyDir{
-		podUID:     podRef.UID,
-		volName:    spec.Name,
-		medium:     medium,
-		mounter:    mounter,
-		mediumer:   mediumer,
-		plugin:     plugin,
-		legacyMode: false,
+		podUID:        podRef.UID,
+		volName:       spec.Name,
+		medium:        medium,
+		mounter:       mounter,
+		mountDetector: mountDetector,
+		plugin:        plugin,
+		legacyMode:    false,
 	}, nil
 }
 
 func (plugin *emptyDirPlugin) NewCleaner(volName string, podUID types.UID) (volume.Cleaner, error) {
 	// Inject real implementations here, test through the internal function.
-	return plugin.newCleanerInternal(volName, podUID, plugin.mounter, &realMediumer{})
+	return plugin.newCleanerInternal(volName, podUID, plugin.mounter, &realMountDetector{})
 }
 
-func (plugin *emptyDirPlugin) newCleanerInternal(volName string, podUID types.UID, mounter mount.Interface, mediumer mediumer) (volume.Cleaner, error) {
+func (plugin *emptyDirPlugin) newCleanerInternal(volName string, podUID types.UID, mounter mount.Interface, mountDetector mountDetector) (volume.Cleaner, error) {
 	legacy := false
 	if plugin.legacyMode {
 		legacy = true
 	}
 	ed := &emptyDir{
-		podUID:     podUID,
-		volName:    volName,
-		medium:     api.StorageTypeDefault, // might be changed later
-		mounter:    mounter,
-		mediumer:   mediumer,
-		plugin:     plugin,
-		legacyMode: legacy,
+		podUID:        podUID,
+		volName:       volName,
+		medium:        api.StorageTypeDefault, // might be changed later
+		mounter:       mounter,
+		mountDetector: mountDetector,
+		plugin:        plugin,
+		legacyMode:    legacy,
 	}
 	return ed, nil
 }
 
-// mediumer abstracts how to find what storageMedium a path is backed by.
-type mediumer interface {
-	GetMedium(path string) (storageMedium, error)
+// mountDetector abstracts how to find what kind of mount a path is backed by.
+type mountDetector interface {
+	// GetMountMedium determines what type of medium a given path is backed
+	// by and whether that path is a mount point.  For example, if this
+	// returns (mediumMemory, false, nil), the caller knows that the path is
+	// on a memory FS (tmpfs on Linux) but is not the root mountpoint of
+	// that tmpfs.
+	GetMountMedium(path string) (storageMedium, bool, error)
 }
 
 type storageMedium int
@@ -142,13 +147,13 @@ const (
 // EmptyDir volumes are temporary directories exposed to the pod.
 // These do not persist beyond the lifetime of a pod.
 type emptyDir struct {
-	podUID     types.UID
-	volName    string
-	medium     api.StorageType
-	mounter    mount.Interface
-	mediumer   mediumer
-	plugin     *emptyDirPlugin
-	legacyMode bool
+	podUID        types.UID
+	volName       string
+	medium        api.StorageType
+	mounter       mount.Interface
+	mountDetector mountDetector
+	plugin        *emptyDirPlugin
+	legacyMode    bool
 }
 
 // SetUp creates new directory.
@@ -183,9 +188,11 @@ func (ed *emptyDir) setupTmpfs(dir string) error {
 		return err
 	}
 	// Make SetUp idempotent.
-	if medium, err := ed.mediumer.GetMedium(dir); err != nil {
+	medium, isMnt, err := ed.mountDetector.GetMountMedium(dir)
+	if err != nil {
 		return err
-	} else if medium == mediumMemory {
+	}
+	if isMnt && medium == mediumMemory {
 		return nil // current state is what we expect
 	}
 	return ed.mounter.Mount("tmpfs", dir, "tmpfs", 0, "")
@@ -207,18 +214,16 @@ func (ed *emptyDir) TearDown() error {
 // TearDownAt simply discards everything in the directory.
 func (ed *emptyDir) TearDownAt(dir string) error {
 	// Figure out the medium.
-	if medium, err := ed.mediumer.GetMedium(dir); err != nil {
+	medium, isMnt, err := ed.mountDetector.GetMountMedium(dir)
+	if err != nil {
 		return err
-	} else {
-		switch medium {
-		case mediumMemory:
-			ed.medium = api.StorageTypeMemory
-			return ed.teardownTmpfs(dir)
-		default:
-			// assume StorageTypeDefault
-			return ed.teardownDefault(dir)
-		}
 	}
+	if isMnt && medium == mediumMemory {
+		ed.medium = api.StorageTypeMemory
+		return ed.teardownTmpfs(dir)
+	}
+	// assume StorageTypeDefault
+	return ed.teardownDefault(dir)
 }
 
 func (ed *emptyDir) teardownDefault(dir string) error {

pkg/kubelet/volume/empty_dir/empty_dir_linux.go

@@ -19,21 +19,27 @@ package empty_dir
 import (
 	"fmt"
 	"syscall"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/mount"
 )
 
 // Defined by Linux - the type number for tmpfs mounts.
 const linuxTmpfsMagic = 0x01021994
 
-// realMediumer implements mediumer in terms of syscalls.
-type realMediumer struct{}
+// realMountDetector implements mountDetector in terms of syscalls.
+type realMountDetector struct{}
 
-func (m *realMediumer) GetMedium(path string) (storageMedium, error) {
+func (m *realMountDetector) GetMountMedium(path string) (storageMedium, bool, error) {
+	isMnt, err := mount.IsMountPoint(path)
+	if err != nil {
+		return 0, false, fmt.Errorf("IsMountPoint(%q): %v", path, err)
+	}
 	buf := syscall.Statfs_t{}
 	if err := syscall.Statfs(path, &buf); err != nil {
-		return 0, fmt.Errorf("statfs(%q): %v", path, err)
+		return 0, false, fmt.Errorf("statfs(%q): %v", path, err)
 	}
 	if buf.Type == linuxTmpfsMagic {
-		return mediumMemory, nil
+		return mediumMemory, isMnt, nil
 	}
-	return mediumUnknown, nil
+	return mediumUnknown, isMnt, nil
 }

pkg/kubelet/volume/empty_dir/empty_dir_test.go

@@ -56,12 +56,13 @@ func TestCanSupport(t *testing.T) {
 	}
 }
 
-type fakeMediumer struct {
-	typeToReturn storageMedium
+type fakeMountDetector struct {
+	medium  storageMedium
+	isMount bool
 }
 
-func (fake *fakeMediumer) GetMedium(path string) (storageMedium, error) {
-	return fake.typeToReturn, nil
+func (fake *fakeMountDetector) GetMountMedium(path string) (storageMedium, bool, error) {
+	return fake.medium, fake.isMount, nil
 }
 
 func TestPlugin(t *testing.T) {
@@ -72,8 +73,8 @@ func TestPlugin(t *testing.T) {
 		VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{Medium: api.StorageTypeDefault}},
 	}
 	mounter := mount.FakeMounter{}
-	mediumer := fakeMediumer{}
-	builder, err := plug.(*emptyDirPlugin).newBuilderInternal(spec, &api.ObjectReference{UID: types.UID("poduid")}, &mounter, &mediumer)
+	mountDetector := fakeMountDetector{}
+	builder, err := plug.(*emptyDirPlugin).newBuilderInternal(spec, &api.ObjectReference{UID: types.UID("poduid")}, &mounter, &mountDetector)
 	if err != nil {
 		t.Errorf("Failed to make a new Builder: %v", err)
 	}
@@ -101,7 +102,7 @@ func TestPlugin(t *testing.T) {
 	}
 	mounter.ResetLog()
 
-	cleaner, err := plug.(*emptyDirPlugin).newCleanerInternal("vol1", types.UID("poduid"), &mounter, &fakeMediumer{})
+	cleaner, err := plug.(*emptyDirPlugin).newCleanerInternal("vol1", types.UID("poduid"), &mounter, &fakeMountDetector{})
 	if err != nil {
 		t.Errorf("Failed to make a new Cleaner: %v", err)
 	}
@@ -131,8 +132,8 @@ func TestPluginTmpfs(t *testing.T) {
 		VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{Medium: api.StorageTypeMemory}},
 	}
 	mounter := mount.FakeMounter{}
-	mediumer := fakeMediumer{}
-	builder, err := plug.(*emptyDirPlugin).newBuilderInternal(spec, &api.ObjectReference{UID: types.UID("poduid")}, &mounter, &mediumer)
+	mountDetector := fakeMountDetector{}
+	builder, err := plug.(*emptyDirPlugin).newBuilderInternal(spec, &api.ObjectReference{UID: types.UID("poduid")}, &mounter, &mountDetector)
 	if err != nil {
 		t.Errorf("Failed to make a new Builder: %v", err)
 	}
@@ -164,7 +165,7 @@ func TestPluginTmpfs(t *testing.T) {
 	}
 	mounter.ResetLog()
 
-	cleaner, err := plug.(*emptyDirPlugin).newCleanerInternal("vol1", types.UID("poduid"), &mounter, &fakeMediumer{mediumMemory})
+	cleaner, err := plug.(*emptyDirPlugin).newCleanerInternal("vol1", types.UID("poduid"), &mounter, &fakeMountDetector{mediumMemory, true})
 	if err != nil {
 		t.Errorf("Failed to make a new Cleaner: %v", err)
 	}
@@ -181,7 +182,7 @@ func TestPluginTmpfs(t *testing.T) {
 		t.Errorf("SetUp() failed: %v", err)
 	}
 	if len(mounter.Log) != 1 {
-		t.Errorf("Expected 1 mounter call, got %#v", mounter.Log)
+		t.Errorf("Expected 1 mounter call, got %d (%v)", len(mounter.Log), mounter.Log)
 	} else {
 		if mounter.Log[0].Action != mount.FakeActionUnmount {
 			t.Errorf("Unexpected mounter action: %#v", mounter.Log[0])
@@ -221,11 +222,11 @@ func TestPluginLegacy(t *testing.T) {
 	}
 
 	spec := api.Volume{VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}
-	if _, err := plug.(*emptyDirPlugin).newBuilderInternal(&spec, &api.ObjectReference{UID: types.UID("poduid")}, &mount.FakeMounter{}, &fakeMediumer{}); err == nil {
+	if _, err := plug.(*emptyDirPlugin).newBuilderInternal(&spec, &api.ObjectReference{UID: types.UID("poduid")}, &mount.FakeMounter{}, &fakeMountDetector{}); err == nil {
 		t.Errorf("Expected failiure")
 	}
 
-	cleaner, err := plug.(*emptyDirPlugin).newCleanerInternal("vol1", types.UID("poduid"), &mount.FakeMounter{}, &fakeMediumer{})
+	cleaner, err := plug.(*emptyDirPlugin).newCleanerInternal("vol1", types.UID("poduid"), &mount.FakeMounter{}, &fakeMountDetector{})
 	if err != nil {
 		t.Errorf("Failed to make a new Cleaner: %v", err)
 	}

pkg/kubelet/volume/empty_dir/empty_dir_unsupported.go

@@ -18,9 +18,9 @@ limitations under the License.
 
 package empty_dir
 
-// realMediumer pretends to implement mediumer.
-type realMediumer struct{}
+// realMountDetector pretends to implement mediumer.
+type realMountDetector struct{}
 
-func (m *realMediumer) GetMedium(path string) (storageMedium, error) {
-	return mediumUnknown, nil
+func (m *realMountDetector) GetMountMedium(path string) (storageMedium, bool, error) {
+	return mediumUnknown, false, nil
 }