Initial implementation

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

apis/controller/v1alpha1/devworkspaceoperatorconfig_types.go

@@ -152,6 +152,12 @@ type PersistentHomeConfig struct {
 	// Must be used with the 'per-user'/'common' or 'per-workspace' storage class in order to take effect.
 	// Disabled by default.
 	Enabled *bool `json:"enabled,omitempty"`
+	// Determines whether the init container that initializes the persistent home directory should be disabled.
+	// When the `/home/user` directory is persisted, the init container is used to initialize the directory before
+	// the workspace starts. If set to true, the init container will not be used.
+	DisableInitContainer *bool `json:"initContainerEnabled,omitempty"`
+	// Image is the container image to use for the init container that initializes the persistent home directory.
+	InitContainer *dw.Container `json:"initContainer,omitempty"`
 }
 
 type Proxy struct {

pkg/constants/constants.go

@@ -41,6 +41,10 @@ const (
 
 	HomeVolumeName = "persistent-home"
 
+	HomeInitComponentName = "init-persistent-home"
+
+	HomeInitEventId = "init-persistent-home"
+
 	ServiceAccount = "devworkspace"
 
 	PVCStorageSize = "10Gi"

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 +46,10 @@ func AddPersistentHomeVolume(workspace *common.DevWorkspaceWithConfig) (*v1alpha
 		Path: constants.HomeUserDirectory,
 	}
 
+	if workspace.Config.Workspace.PersistUserHome.DisableInitContainer == nil || !*workspace.Config.Workspace.PersistUserHome.DisableInitContainer {
+		addInitContainer(dwTemplateSpecCopy, workspace.Config.Workspace.PersistUserHome.InitContainer)
+	}
+
 	dwTemplateSpecCopy.Components = append(dwTemplateSpecCopy.Components, homeVolume)
 	for _, component := range dwTemplateSpecCopy.Components {
 		if component.Container == nil {
@@ -95,3 +101,64 @@ func storageStrategySupportsPersistentHome(workspace *common.DevWorkspaceWithCon
 	storageClass := workspace.Spec.Template.Attributes.GetString(constants.DevWorkspaceStorageTypeAttribute, nil)
 	return storageClass != constants.EphemeralStorageClassType
 }
+
+func addInitContainer(dwTemplateSpec *v1alpha2.DevWorkspaceTemplateSpec, initContainerFromConfig *v1alpha2.Container) {
+
+	initContainerComponent := v1alpha2.Component{
+		Name: constants.HomeInitComponentName,
+	}
+
+	initContainer := initContainerFromConfig
+
+	if initContainer == nil {
+		initContainer = inferInitContainer(dwTemplateSpec)
+	}
+
+	if initContainer == nil {
+		return
+	}
+
+	initContainerComponent.ComponentUnion = v1alpha2.ComponentUnion{
+		Container: &v1alpha2.ContainerComponent{
+			Container: *initContainer,
+		},
+	}
+
+	dwTemplateSpec.Components = append(dwTemplateSpec.Components, initContainerComponent)
+	dwTemplateSpec.Commands = append(dwTemplateSpec.Commands, v1alpha2.Command{
+		Id: constants.HomeInitEventId,
+		CommandUnion: v1alpha2.CommandUnion{
+			Apply: &v1alpha2.ApplyCommand{
+				Component: constants.HomeInitComponentName,
+			},
+		},
+	})
+	dwTemplateSpec.Events.PreStart = append(dwTemplateSpec.Events.PreStart, constants.HomeInitEventId)
+}
+
+func inferInitContainer(dwTemplateSpec *v1alpha2.DevWorkspaceTemplateSpec) *v1alpha2.Container {
+	var firstUnflattenedComponent v1alpha2.Component
+	for _, component := range dwTemplateSpec.Components {
+		if component.Container == nil {
+			continue
+		}
+
+		var err error
+		component.Attributes.Get(constants.MergedContributionsAttribute, &err)
+		if err == nil {
+			firstUnflattenedComponent = component
+			break
+		}
+	}
+
+	if firstUnflattenedComponent.Name != "" {
+		image := firstUnflattenedComponent.Container.Image
+		command := []string{"/bin/sh", "-c", "/entrypoint.sh || true"}
+
+		return &v1alpha2.Container{
+			Image:   image,
+			Command: command,
+		}
+	}
+	return nil
+}