Prepare support in kube play for other volume types than hostPath

Replace the simple map of names to paths with a map of names to a struct
to allow passing more parameters. Also move the code to parse the volumes
to its own file to avoid making the playKubePod() function overly complex.
Finally rework the kube volumes test to also be ready to support more
volume types.

Signed-off-by: Alban Bedel <albeu@free.fr>

2 files changed, 131 insertions, 13 deletions

diff --git a/pkg/specgen/generate/kube/kube.go b/pkg/specgen/generate/kube/kube.go
index e1202956c..aee30b652 100644
--- a/pkg/specgen/generate/kube/kube.go
+++ b/pkg/specgen/generate/kube/kube.go
@@ -47,7 +47,7 @@ func ToPodGen(ctx context.Context, podName string, podYAML *v1.PodTemplateSpec)
 	return p, nil
 }
 
-func ToSpecGen(ctx context.Context, containerYAML v1.Container, iid string, newImage *image.Image, volumes map[string]string, podID, podName, infraID string, configMaps []v1.ConfigMap, seccompPaths *KubeSeccompPaths, restartPolicy string) (*specgen.SpecGenerator, error) {
+func ToSpecGen(ctx context.Context, containerYAML v1.Container, iid string, newImage *image.Image, volumes map[string]*KubeVolume, podID, podName, infraID string, configMaps []v1.ConfigMap, seccompPaths *KubeSeccompPaths, restartPolicy string) (*specgen.SpecGenerator, error) {
 	s := specgen.NewSpecGenerator(iid, false)
 
 	// podName should be non-empty for Deployment objects to be able to create
@@ -163,22 +163,27 @@ func ToSpecGen(ctx context.Context, containerYAML v1.Container, iid string, newI
 	s.Env = envs
 
 	for _, volume := range containerYAML.VolumeMounts {
-		hostPath, exists := volumes[volume.Name]
+		volumeSource, exists := volumes[volume.Name]
 		if !exists {
 			return nil, errors.Errorf("Volume mount %s specified for container but not configured in volumes", volume.Name)
 		}
-		if err := parse.ValidateVolumeCtrDir(volume.MountPath); err != nil {
-			return nil, errors.Wrapf(err, "error in parsing MountPath")
-		}
-		mount := spec.Mount{
-			Destination: volume.MountPath,
-			Source:      hostPath,
-			Type:        "bind",
-		}
-		if volume.ReadOnly {
-			mount.Options = []string{"ro"}
+		switch volumeSource.Type {
+		case KubeVolumeTypeBindMount:
+			if err := parse.ValidateVolumeCtrDir(volume.MountPath); err != nil {
+				return nil, errors.Wrapf(err, "error in parsing MountPath")
+			}
+			mount := spec.Mount{
+				Destination: volume.MountPath,
+				Source:      volumeSource.Source,
+				Type:        "bind",
+			}
+			if volume.ReadOnly {
+				mount.Options = []string{"ro"}
+			}
+			s.Mounts = append(s.Mounts, mount)
+		default:
+			return nil, errors.Errorf("Unsupported volume source type")
 		}
-		s.Mounts = append(s.Mounts, mount)
 	}
 
 	s.RestartPolicy = restartPolicy
diff --git a/pkg/specgen/generate/kube/volume.go b/pkg/specgen/generate/kube/volume.go
new file mode 100644
index 000000000..b24583e8e
--- /dev/null
+++ b/pkg/specgen/generate/kube/volume.go
@@ -0,0 +1,113 @@
+package kube
+
+import (
+	"os"
+
+	"github.com/containers/buildah/pkg/parse"
+	"github.com/containers/podman/v2/libpod"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	v1 "k8s.io/api/core/v1"
+)
+
+const (
+	// https://kubernetes.io/docs/concepts/storage/volumes/#hostpath
+	kubeDirectoryPermission = 0755
+	// https://kubernetes.io/docs/concepts/storage/volumes/#hostpath
+	kubeFilePermission = 0644
+)
+
+type KubeVolumeType int
+
+const (
+	KubeVolumeTypeBindMount KubeVolumeType = iota
+)
+
+type KubeVolume struct {
+	// Type of volume to create
+	Type KubeVolumeType
+	// Path for bind mount
+	Source string
+}
+
+// Create a KubeVolume from an HostPathVolumeSource
+func VolumeFromHostPath(hostPath *v1.HostPathVolumeSource) (*KubeVolume, error) {
+	if hostPath.Type != nil {
+		switch *hostPath.Type {
+		case v1.HostPathDirectoryOrCreate:
+			if _, err := os.Stat(hostPath.Path); os.IsNotExist(err) {
+				if err := os.Mkdir(hostPath.Path, kubeDirectoryPermission); err != nil {
+					return nil, err
+				}
+			}
+			// Label a newly created volume
+			if err := libpod.LabelVolumePath(hostPath.Path); err != nil {
+				return nil, errors.Wrapf(err, "error giving %s a label", hostPath.Path)
+			}
+		case v1.HostPathFileOrCreate:
+			if _, err := os.Stat(hostPath.Path); os.IsNotExist(err) {
+				f, err := os.OpenFile(hostPath.Path, os.O_RDONLY|os.O_CREATE, kubeFilePermission)
+				if err != nil {
+					return nil, errors.Wrap(err, "error creating HostPath")
+				}
+				if err := f.Close(); err != nil {
+					logrus.Warnf("Error in closing newly created HostPath file: %v", err)
+				}
+			}
+			// unconditionally label a newly created volume
+			if err := libpod.LabelVolumePath(hostPath.Path); err != nil {
+				return nil, errors.Wrapf(err, "error giving %s a label", hostPath.Path)
+			}
+		case v1.HostPathSocket:
+			st, err := os.Stat(hostPath.Path)
+			if err != nil {
+				return nil, errors.Wrap(err, "error checking HostPathSocket")
+			}
+			if st.Mode()&os.ModeSocket != os.ModeSocket {
+				return nil, errors.Errorf("error checking HostPathSocket: path %s is not a socket", hostPath.Path)
+			}
+
+		case v1.HostPathDirectory:
+		case v1.HostPathFile:
+		case v1.HostPathUnset:
+			// do nothing here because we will verify the path exists in validateVolumeHostDir
+			break
+		default:
+			return nil, errors.Errorf("Invalid HostPath type %v", hostPath.Type)
+		}
+	}
+
+	if err := parse.ValidateVolumeHostDir(hostPath.Path); err != nil {
+		return nil, errors.Wrapf(err, "error in parsing HostPath in YAML")
+	}
+
+	return &KubeVolume{
+		Type:   KubeVolumeTypeBindMount,
+		Source: hostPath.Path,
+	}, nil
+}
+
+// Create a KubeVolume from one of the supported VolumeSource
+func VolumeFromSource(volumeSource v1.VolumeSource) (*KubeVolume, error) {
+	if volumeSource.HostPath != nil {
+		return VolumeFromHostPath(volumeSource.HostPath)
+	} else {
+		return nil, errors.Errorf("HostPath is currently the only supported VolumeSource")
+	}
+}
+
+// Create a map of volume name to KubeVolume
+func InitializeVolumes(specVolumes []v1.Volume) (map[string]*KubeVolume, error) {
+	volumes := make(map[string]*KubeVolume)
+
+	for _, specVolume := range specVolumes {
+		volume, err := VolumeFromSource(specVolume.VolumeSource)
+		if err != nil {
+			return nil, err
+		}
+
+		volumes[specVolume.Name] = volume
+	}
+
+	return volumes, nil
+}