Initial implementation

Signed-off-by: David Kwon <[email protected]>

pkg/library/home/persistentHome.go

@@ -29,6 +29,8 @@ import (
 
 // Returns a modified copy of the given DevWorkspace's Template Spec which contains an additional
 // Devfile volume 'persistentHome' that is mounted  to `/home/user/` for every container component defined in the DevWorkspace.
+// This feature assumes that the container image of the first merged container component in the unflattened devfile contains an
+// /entrypoint.sh script that initializes persistentHome for the homeVolumeMount PVC.
 // An error is returned if the addition of the 'persistentHome' volume would result
 // in an invalid DevWorkspace.
 func AddPersistentHomeVolume(workspace *common.DevWorkspaceWithConfig) (*v1alpha2.DevWorkspaceTemplateSpec, error) {
@@ -44,6 +46,24 @@ func AddPersistentHomeVolume(workspace *common.DevWorkspaceWithConfig) (*v1alpha
 		Path: constants.HomeUserDirectory,
 	}
 
+	var firstUnflattenedComponent v1alpha2.Component
+	for _, component := range dwTemplateSpecCopy.Components {
+		if component.Container == nil {
+			continue
+		}
+
+		var err error
+		component.Attributes.Get(constants.MergedContributionsAttribute, &err)
+		if err == nil {
+			firstUnflattenedComponent = component
+			break
+		}
+	}
+
+	if firstUnflattenedComponent.Name != "" {
+		addPersistentStorageInitContainer(dwTemplateSpecCopy, firstUnflattenedComponent.Container.Image)
+	}
+
 	dwTemplateSpecCopy.Components = append(dwTemplateSpecCopy.Components, homeVolume)
 	for _, component := range dwTemplateSpecCopy.Components {
 		if component.Container == nil {
@@ -95,3 +115,32 @@ func storageStrategySupportsPersistentHome(workspace *common.DevWorkspaceWithCon
 	storageClass := workspace.Spec.Template.Attributes.GetString(constants.DevWorkspaceStorageTypeAttribute, nil)
 	return storageClass != constants.EphemeralStorageClassType
 }
+
+// Add an init container that runs /entrypoint.sh to initialize the persistent home directory.
+// This function assumes that the provided image contains the /entrypoint.sh script.
+// If the script is not present in the image, the init container will not fail the workspace from starting.
+func addPersistentStorageInitContainer(dwTemplateSpecCopy *v1alpha2.DevWorkspaceTemplateSpec, image string) {
+	initContainerComponent := v1alpha2.Component{
+		Name: "init-persistent-home",
+		ComponentUnion: v1alpha2.ComponentUnion{
+			Container: &v1alpha2.ContainerComponent{
+				Container: v1alpha2.Container{
+					Image:   image,
+					Command: []string{"/bin/sh", "-c", "/entrypoint.sh || true"},
+				},
+			},
+		},
+	}
+
+	dwTemplateSpecCopy.Components = append(dwTemplateSpecCopy.Components, initContainerComponent)
+
+	dwTemplateSpecCopy.Commands = append(dwTemplateSpecCopy.Commands, v1alpha2.Command{
+		Id: "init-persistent-home",
+		CommandUnion: v1alpha2.CommandUnion{
+			Apply: &v1alpha2.ApplyCommand{
+				Component: "init-persistent-home",
+			},
+		},
+	})
+	dwTemplateSpecCopy.Events.PreStart = append(dwTemplateSpecCopy.Events.PreStart, "init-persistent-home")
+}