distro: add workload to image type

Support specifying workload on an image type.
This isn't used yet, but when set, the workload will define packages and
services and not allow any blueprint customizations.

In the future, there will be multiple workloads with each image type
specifying one (but multiple image types can have the same default
workload).  The custom workload will allow all customizations that are
currently supported.

internal/distro/rhel7/distro.go

@@ -213,6 +213,7 @@ type imageType struct {
 	arch               *architecture
 	platform           platform.Platform
 	environment        environment.Environment
+	workload           workload.Workload
 	name               string
 	nameAliases        []string
 	filename           string
@@ -346,17 +347,19 @@ func (t *imageType) initializeManifest(bp *blueprint.Blueprint,
 		return nil, err
 	}
 
-	// TODO: let image types specify valid workloads, rather than
-	// always assume Custom.
-	w := &workload.Custom{
-		BaseWorkload: workload.BaseWorkload{
-			Repos: packageSets[blueprintPkgsKey].Repositories,
-		},
-		Packages: bp.GetPackagesEx(false),
-	}
-	if services := bp.Customizations.GetServices(); services != nil {
-		w.Services = services.Enabled
-		w.DisabledServices = services.Disabled
+	w := t.workload
+	if w == nil {
+		cw := &workload.Custom{
+			BaseWorkload: workload.BaseWorkload{
+				Repos: packageSets[blueprintPkgsKey].Repositories,
+			},
+			Packages: bp.GetPackagesEx(false),
+		}
+		if services := bp.Customizations.GetServices(); services != nil {
+			cw.Services = services.Enabled
+			cw.DisabledServices = services.Disabled
+		}
+		w = cw
 	}
 
 	source := rand.NewSource(seed)
@@ -503,6 +506,17 @@ func overridePackageNames(packages []string) []string {
 // checkOptions checks the validity and compatibility of options and customizations for the image type.
 func (t *imageType) checkOptions(customizations *blueprint.Customizations, options distro.ImageOptions, containers []container.Spec) error {
 
+	if t.workload != nil {
+		// For now, if an image type defines its own workload, don't allow any
+		// user customizations.
+		// Soon we will have more workflows and each will define its allowed
+		// set of customizations.  The current set of customizations defined in
+		// the blueprint spec corresponds to the Custom workflow.
+		if customizations != nil {
+			return fmt.Errorf("image type %q does not support customizations", t.name)
+		}
+	}
+
 	if len(containers) > 0 {
 		return fmt.Errorf("embedding containers is not supported for %s on %s", t.name, t.arch.distro.name)
 	}

internal/distro/rhel8/imagetype.go

@@ -48,6 +48,7 @@ type imageType struct {
 	arch               *architecture
 	platform           platform.Platform
 	environment        environment.Environment
+	workload           workload.Workload
 	name               string
 	nameAliases        []string
 	filename           string
@@ -193,17 +194,19 @@ func (t *imageType) initializeManifest(bp *blueprint.Blueprint,
 		return nil, err
 	}
 
-	// TODO: let image types specify valid workloads, rather than
-	// always assume Custom.
-	w := &workload.Custom{
-		BaseWorkload: workload.BaseWorkload{
-			Repos: packageSets[blueprintPkgsKey].Repositories,
-		},
-		Packages: bp.GetPackagesEx(false),
-	}
-	if services := bp.Customizations.GetServices(); services != nil {
-		w.Services = services.Enabled
-		w.DisabledServices = services.Disabled
+	w := t.workload
+	if w == nil {
+		cw := &workload.Custom{
+			BaseWorkload: workload.BaseWorkload{
+				Repos: packageSets[blueprintPkgsKey].Repositories,
+			},
+			Packages: bp.GetPackagesEx(false),
+		}
+		if services := bp.Customizations.GetServices(); services != nil {
+			cw.Services = services.Enabled
+			cw.DisabledServices = services.Disabled
+		}
+		w = cw
 	}
 
 	source := rand.NewSource(seed)
@@ -368,6 +371,17 @@ func overridePackageNames(packages []string) []string {
 // checkOptions checks the validity and compatibility of options and customizations for the image type.
 func (t *imageType) checkOptions(customizations *blueprint.Customizations, options distro.ImageOptions, containers []container.Spec) error {
 
+	if t.workload != nil {
+		// For now, if an image type defines its own workload, don't allow any
+		// user customizations.
+		// Soon we will have more workflows and each will define its allowed
+		// set of customizations.  The current set of customizations defined in
+		// the blueprint spec corresponds to the Custom workflow.
+		if customizations != nil {
+			return fmt.Errorf("image type %q does not support customizations", t.name)
+		}
+	}
+
 	// we do not support embedding containers on ostree-derived images, only on commits themselves
 	if len(containers) > 0 && t.rpmOstree && (t.name != "edge-commit" && t.name != "edge-container") {
 		return fmt.Errorf("embedding containers is not supported for %s on %s", t.name, t.arch.distro.name)

internal/distro/rhel9/imagetype.go

@@ -51,6 +51,7 @@ type imageType struct {
 	arch               *architecture
 	platform           platform.Platform
 	environment        environment.Environment
+	workload           workload.Workload
 	name               string
 	nameAliases        []string
 	filename           string
@@ -196,17 +197,19 @@ func (t *imageType) initializeManifest(bp *blueprint.Blueprint,
 		return nil, err
 	}
 
-	// TODO: let image types specify valid workloads, rather than
-	// always assume Custom.
-	w := &workload.Custom{
-		BaseWorkload: workload.BaseWorkload{
-			Repos: packageSets[blueprintPkgsKey].Repositories,
-		},
-		Packages: bp.GetPackagesEx(false),
-	}
-	if services := bp.Customizations.GetServices(); services != nil {
-		w.Services = services.Enabled
-		w.DisabledServices = services.Disabled
+	w := t.workload
+	if w == nil {
+		cw := &workload.Custom{
+			BaseWorkload: workload.BaseWorkload{
+				Repos: packageSets[blueprintPkgsKey].Repositories,
+			},
+			Packages: bp.GetPackagesEx(false),
+		}
+		if services := bp.Customizations.GetServices(); services != nil {
+			cw.Services = services.Enabled
+			cw.DisabledServices = services.Disabled
+		}
+		w = cw
 	}
 
 	source := rand.NewSource(seed)
@@ -336,6 +339,17 @@ func (t *imageType) PackageSets(bp blueprint.Blueprint, options distro.ImageOpti
 // checkOptions checks the validity and compatibility of options and customizations for the image type.
 func (t *imageType) checkOptions(customizations *blueprint.Customizations, options distro.ImageOptions, containers []container.Spec) error {
 
+	if t.workload != nil {
+		// For now, if an image type defines its own workload, don't allow any
+		// user customizations.
+		// Soon we will have more workflows and each will define its allowed
+		// set of customizations.  The current set of customizations defined in
+		// the blueprint spec corresponds to the Custom workflow.
+		if customizations != nil {
+			return fmt.Errorf("image type %q does not support customizations", t.name)
+		}
+	}
+
 	// we do not support embedding containers on ostree-derived images, only on commits themselves
 	if len(containers) > 0 && t.rpmOstree && (t.name != "edge-commit" && t.name != "edge-container") {
 		return fmt.Errorf("embedding containers is not supported for %s on %s", t.name, t.arch.distro.name)