Add label support to named volumes in docker compose v3 to Kubernetes (#1083)

* Support read specific label (kompose.volume.size) from named volume and apply to kubernetes supported volume size

* Fix the PVC size in log message when deploy Kubernetes

* Skip creation of PersistentVolumeClaim if it is already created in the same kubernetes deploy

* Add selector to PersistentVolumeClaim only when specific label (kompose.volume.selector) is used in named volume

* Add test case to named-volume for the new labels

pkg/kobject/kobject.go

@@ -143,13 +143,14 @@ type Ports struct {
 
 // Volumes holds the volume struct of container
 type Volumes struct {
-	SvcName    string // Service name to which volume is linked
-	MountPath  string // Mountpath extracted from docker-compose file
-	VFrom      string // denotes service name from which volume is coming
-	VolumeName string // name of volume if provided explicitly
-	Host       string // host machine address
-	Container  string // Mountpath
-	Mode       string // access mode for volume
-	PVCName    string // name of PVC
-	PVCSize    string // PVC size
+	SvcName       string // Service name to which volume is linked
+	MountPath     string // Mountpath extracted from docker-compose file
+	VFrom         string // denotes service name from which volume is coming
+	VolumeName    string // name of volume if provided explicitly
+	Host          string // host machine address
+	Container     string // Mountpath
+	Mode          string // access mode for volume
+	PVCName       string // name of PVC
+	PVCSize       string // PVC size
+	SelectorValue string // Value of the label selector
 }

pkg/loader/compose/v3.go

@@ -422,11 +422,51 @@ func dockerComposeToKomposeMapping(composeObject *types.Config) (kobject.Kompose
 		komposeObject.ServiceConfigs[normalizeServiceNames(name)] = serviceConfig
 	}
 
-	handleVolume(&komposeObject)
+	handleV3Volume(&komposeObject, &composeObject.Volumes)
 
 	return komposeObject, nil
 }
 
+func handleV3Volume(komposeObject *kobject.KomposeObject, volumes *map[string]types.VolumeConfig) {
+	for name := range komposeObject.ServiceConfigs {
+		// retrieve volumes of service
+		vols, err := retrieveVolume(name, *komposeObject)
+		if err != nil {
+			errors.Wrap(err, "could not retrieve vvolume")
+		}
+		for volName, vol := range vols {
+			size, selector := getV3VolumeLabels(vol.VolumeName, volumes)
+			if len(size) > 0 || len(selector) > 0 {
+				// We can't assign value to struct field in map while iterating over it, so temporary variable `temp` is used here
+				var temp = vols[volName]
+				temp.PVCSize = size
+				temp.SelectorValue = selector
+				vols[volName] = temp
+			}
+		}
+		// We can't assign value to struct field in map while iterating over it, so temporary variable `temp` is used here
+		var temp = komposeObject.ServiceConfigs[name]
+		temp.Volumes = vols
+		komposeObject.ServiceConfigs[name] = temp
+	}
+}
+
+func getV3VolumeLabels(name string, volumes *map[string]types.VolumeConfig) (string, string) {
+	size, selector := "", ""
+
+	if volume, ok := (*volumes)[name]; ok {
+		for key, value := range volume.Labels {
+			if key == "kompose.volume.size" {
+				size = value
+			} else if key == "kompose.volume.selector" {
+				selector = value
+			}
+		}
+	}
+
+	return size, selector
+}
+
 func mergeComposeObject(oldCompose *types.Config, newCompose *types.Config) (*types.Config, error) {
 	if oldCompose == nil || newCompose == nil {
 		return nil, fmt.Errorf("Merge multiple compose error, compose config is nil")

pkg/transformer/kubernetes/kubernetes.go

@@ -373,7 +373,7 @@ func (k *Kubernetes) initIngress(name string, service kobject.ServiceConfig, por
 }
 
 // CreatePVC initializes PersistentVolumeClaim
-func (k *Kubernetes) CreatePVC(name string, mode string, size string) (*api.PersistentVolumeClaim, error) {
+func (k *Kubernetes) CreatePVC(name string, mode string, size string, selectorValue string) (*api.PersistentVolumeClaim, error) {
 	volSize, err := resource.ParseQuantity(size)
 	if err != nil {
 		return nil, errors.Wrap(err, "resource.ParseQuantity failed, Error parsing size")
@@ -397,6 +397,12 @@ func (k *Kubernetes) CreatePVC(name string, mode string, size string) (*api.Pers
 		},
 	}
 
+	if len(selectorValue) > 0 {
+		pvc.Spec.Selector = &unversioned.LabelSelector{
+			MatchLabels: transformer.ConfigLabels(selectorValue),
+		}
+	}
+
 	if mode == "ro" {
 		pvc.Spec.AccessModes = []api.PersistentVolumeAccessMode{api.ReadOnlyMany}
 	} else {
@@ -578,13 +584,17 @@ func (k *Kubernetes) ConfigVolumes(name string, service kobject.ServiceConfig) (
 			if volume.VFrom == "" {
 				defaultSize := PVCRequestSize
 
-				for key, value := range service.Labels {
-					if key == "kompose.volume.size" {
-						defaultSize = value
+				if len(volume.PVCSize) > 0 {
+					defaultSize = volume.PVCSize
+				} else {
+					for key, value := range service.Labels {
+						if key == "kompose.volume.size" {
+							defaultSize = value
+						}
 					}
 				}
 
-				createdPVC, err := k.CreatePVC(volumeName, volume.Mode, defaultSize)
+				createdPVC, err := k.CreatePVC(volumeName, volume.Mode, defaultSize, volume.SelectorValue)
 
 				if err != nil {
 					return nil, nil, nil, errors.Wrap(err, "k.CreatePVC failed")
@@ -978,6 +988,8 @@ func (k *Kubernetes) Deploy(komposeObject kobject.KomposeObject, opt kobject.Con
 		return err
 	}
 
+	pvcCreatedSet := make(map[string]bool)
+
 	log.Infof("Deploying application in %q namespace", namespace)
 
 	for _, v := range objects {
@@ -1010,11 +1022,18 @@ func (k *Kubernetes) Deploy(komposeObject kobject.KomposeObject, opt kobject.Con
 			}
 			log.Infof("Successfully created Service: %s", t.Name)
 		case *api.PersistentVolumeClaim:
-			_, err := client.PersistentVolumeClaims(namespace).Create(t)
-			if err != nil {
-				return err
+			if pvcCreatedSet[t.Name] {
+				log.Infof("Skip creation of PersistentVolumeClaim as it is already created: %s", t.Name)
+			} else {
+				_, err := client.PersistentVolumeClaims(namespace).Create(t)
+				if err != nil {
+					return err
+				}
+				pvcCreatedSet[t.Name] = true
+				storage := t.Spec.Resources.Requests[api.ResourceStorage]
+				capacity := storage.String()
+				log.Infof("Successfully created PersistentVolumeClaim: %s of size %s. If your cluster has dynamic storage provisioning, you don't have to do anything. Otherwise you have to create PersistentVolume to make PVC work", t.Name, capacity)
 			}
-			log.Infof("Successfully created PersistentVolumeClaim: %s of size %s. If your cluster has dynamic storage provisioning, you don't have to do anything. Otherwise you have to create PersistentVolume to make PVC work", t.Name, PVCRequestSize)
 		case *extensions.Ingress:
 			_, err := client.Ingress(namespace).Create(t)
 			if err != nil {