Imrove project plumbing

internal/cli/cli.go

@@ -82,33 +82,33 @@ func Setup(name string, define func(*cobra.Command), initialize func(context.Con
 			return nil
 		}
 
-		err := cfg.BindPFlags(cmd.Flags())
-		if err != nil {
-			return fmt.Errorf("cannot bind flags: %w", err)
+		inErr := cfg.BindPFlags(cmd.Flags())
+		if inErr != nil {
+			return fmt.Errorf("cannot bind flags: %w", inErr)
 		}
-		err = cfg.BindPFlags(cmd.InheritedFlags())
-		if err != nil {
-			return fmt.Errorf("cannot bind inherited flags: %w", err)
+		inErr = cfg.BindPFlags(cmd.InheritedFlags())
+		if inErr != nil {
+			return fmt.Errorf("cannot bind inherited flags: %w", inErr)
 		}
 
 		cfgFile := cfg.GetString("config-file")
 		if cfgFile != "" {
 			cfg.SetConfigFile(cfgFile)
 		}
 
-		err = cfg.ReadInConfig()
-		if err != nil {
-			_, ok := errors.AsType[viper.ConfigFileNotFoundError](err)
+		inErr = cfg.ReadInConfig()
+		if inErr != nil {
+			_, ok := errors.AsType[viper.ConfigFileNotFoundError](inErr)
 			if cfgFile != "" || !ok {
-				return fmt.Errorf("cannot read config file: %w", err)
+				return fmt.Errorf("cannot read config file: %w", inErr)
 			}
 		}
 
 		if initialize != nil {
 			var ctx context.Context
-			ctx, err = initialize(cmd.Context(), cfg)
-			if err != nil {
-				return fmt.Errorf("cannot initialize: %w", err)
+			ctx, inErr = initialize(cmd.Context(), cfg)
+			if inErr != nil {
+				return fmt.Errorf("cannot initialize: %w", inErr)
 			}
 			//nolint:fatcontext // This is required for ctxFunc closure to return the initialized context.
 			initializedCtx = ctx

internal/cloudprovider/aliyun.go

@@ -261,7 +261,7 @@ func (p *aliyun) Publish(ctx context.Context, cname string, manifest *gardenlinu
 	images := make(map[string]string, len(ecsClients))
 	publishImages := parallel.NewLimitedActivitySync(ctx, 7)
 	for toRegion := range ecsClients {
-		publishImages.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+		publishImages.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 			ctx = log.WithValues(ctx, "region", toRegion)
 			localID := imageID
 			var er error

internal/cloudprovider/aws.go

@@ -462,7 +462,7 @@ func (p *awsTarget) Publish(ctx context.Context, cname string, manifest *gardenl
 	outputImages := make([]awsPublishedImage, 0, 4)
 	publish := parallel.NewActivitySync(ctx)
 
-	publish.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+	publish.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 		ctx = log.WithValues(ctx, "cloud", "public")
 
 		images, er := p.publish(ctx, p.source, imagePath.S3Key, image, tags, arch, requireUEFI, uefiData, false)
@@ -477,7 +477,7 @@ func (p *awsTarget) Publish(ctx context.Context, cname string, manifest *gardenl
 	})
 
 	if p.enableChina && !secureBoot {
-		publish.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+		publish.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 			ctx = log.WithValues(ctx, "cloud", "china")
 
 			source := p.sourceChina
@@ -545,7 +545,7 @@ func (p *awsTarget) publish(ctx context.Context, source ArtifactSource, key, ima
 	images := make(map[string]string, len(regions))
 	publishImages := parallel.NewLimitedActivitySync(ctx, 12)
 	for _, toRegion := range regions {
-		publishImages.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+		publishImages.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 			ctx = log.WithValues(ctx, "region", toRegion)
 			localID := imageID
 			var er error

internal/cloudprovider/azure.go

@@ -461,7 +461,7 @@ func (p *azure) Publish(ctx context.Context, cname string, manifest *gardenlinux
 	outputImages := make([]azurePublishedImage, 0, 4)
 	publish := parallel.NewActivitySync(ctx)
 
-	publish.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+	publish.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 		ctx = log.WithValues(ctx, "cloud", "public")
 
 		images, er := p.publish(ctx, cname, p.source, imagePath.S3Key, image, imageVersion, arch, bios, secureBoot, pk, kek, db, false)
@@ -476,7 +476,7 @@ func (p *azure) Publish(ctx context.Context, cname string, manifest *gardenlinux
 	})
 
 	if p.enableChina {
-		publish.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+		publish.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 			ctx = log.WithValues(ctx, "cloud", "china")
 
 			source := p.sourceChina
@@ -577,7 +577,7 @@ func (p *azure) publish(ctx context.Context, cname string, source ArtifactSource
 
 	if bios {
 		blobUsed.Add(1)
-		createImageVersion.Go(func(_ context.Context) (parallel.ResultFunc, error) {
+		createImageVersion.Go(func(_ context.Context) (parallel.ResultSyncFunc, error) {
 			imageID, er := func() (string, error) {
 				defer blobUsed.Done()
 				return p.createImage(bctx, blobURL, image, true, china)
@@ -610,7 +610,7 @@ func (p *azure) publish(ctx context.Context, cname string, source ArtifactSource
 		})
 	}
 
-	createImageVersion.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+	createImageVersion.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 		imageID, er := func() (string, error) {
 			defer blobUsed.Done()
 			return p.createImage(ctx, blobURL, image, false, china)
@@ -641,7 +641,7 @@ func (p *azure) publish(ctx context.Context, cname string, source ArtifactSource
 		}, nil
 	})
 
-	createImageVersion.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+	createImageVersion.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 		blobUsed.Wait()
 
 		er := p.deleteBlob(ctx, blob, false, china)

internal/cloudprovider/openstack.go

@@ -111,7 +111,7 @@ func (p *openstack) createClients(ctx context.Context, config openstackPublishin
 
 	initClients := parallel.NewLimitedActivitySync(ctx, 7)
 	for _, region := range config.Regions {
-		initClients.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+		initClients.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 			providerClient, er := openstacksdk.AuthenticatedClient(ctx, gophercloud.AuthOptions{
 				IdentityEndpoint: strings.Replace(config.Endpoint, "{region}", region, 1),
 				Username:         creds.Username,
@@ -271,7 +271,7 @@ func (p *openstack) Publish(ctx context.Context, cname string, manifest *gardenl
 				source = p.sourceChina
 			}
 
-			publishImages.Go(func(ctx context.Context) (parallel.ResultFunc, error) {
+			publishImages.Go(func(ctx context.Context) (parallel.ResultSyncFunc, error) {
 				ctx = log.WithValues(ctx, "region", region)
 
 				ctx = task.Begin(ctx, "publish/"+image+"/"+region, &openstackTaskState{

internal/graph/dfs.go

@@ -16,16 +16,28 @@ func (e *CycleError[N]) Error() string {
 
 // ReverseTopologicalSort runs DFS from each root and returns the nodes in reverse topological order or *CycleError if there is a cycle.
 func ReverseTopologicalSort[N comparable](roots []N, neighbors func(N) ([]N, error)) ([]N, error) {
-	return DFS(roots, neighbors, PostOrder)
+	return DFS(roots, neighbors, PostOrder, CyclesError)
 }
 
-// ReachableSet runs DFS from each root and returns every reachable node in pre-order or *CycleError if there is a cycle.
+// ReachableSet runs DFS from each root and returns every reachable node in pre-order, allowing cycles.
 func ReachableSet[N comparable](roots []N, neighbors func(N) ([]N, error)) ([]N, error) {
-	return DFS(roots, neighbors, PreOrder)
+	return DFS(roots, neighbors, PreOrder, CyclesAllow)
 }
 
-// DFS runs depth-first search from each root and returns the visited nodes in the requested order or *CycleError if there is a cycle.
-func DFS[N comparable](roots []N, neighbors func(N) ([]N, error), order Order) ([]N, error) {
+// DFS runs depth-first search from each root and returns the visited nodes in the requested order. Back-edges are handled per cycles.
+func DFS[N comparable](roots []N, neighbors func(N) ([]N, error), order Order, cycles Cycles) ([]N, error) {
+	switch order {
+	case PreOrder, PostOrder:
+	default:
+		return nil, fmt.Errorf("invalid order %d", order)
+	}
+
+	switch cycles {
+	case CyclesAllow, CyclesError:
+	default:
+		return nil, fmt.Errorf("invalid cycles mode %d", cycles)
+	}
+
 	const (
 		white = 0
 		gray  = 1
@@ -65,6 +77,10 @@ func DFS[N comparable](roots []N, neighbors func(N) ([]N, error), order Order) (
 
 		c := color[f.node]
 		if c == gray {
+			if cycles == CyclesAllow {
+				continue
+			}
+
 			start := slices.Index(path, f.node)
 			return nil, &CycleError[N]{
 				Cycle: append([]N(nil), path[start:]...),

internal/graph/graph.go

@@ -9,3 +9,13 @@ const (
 	// PostOrder visits each node after its children.
 	PostOrder
 )
+
+// Cycles controls how DFS reacts to a back-edge, an edge to a node already on the current path.
+type Cycles int
+
+const (
+	// CyclesAllow makes DFS skip a back-edge and continue the walk.
+	CyclesAllow Cycles = iota + 1
+	// CyclesError makes DFS return a *CycleError on any back-edge.
+	CyclesError
+)

internal/module/module.go

@@ -73,7 +73,7 @@ func (r *Root) Init(rawCfg map[string]any) error {
 	}
 
 	var modules []Module
-	modules, err = r.allModules()
+	modules, err = r.AllModules()
 	if err != nil {
 		return fmt.Errorf("invalid configuration: %w", err)
 	}
@@ -103,8 +103,9 @@ func (r *Root) Init(rawCfg map[string]any) error {
 	return nil
 }
 
-func (r *Root) allModules() ([]Module, error) {
-	configurables, err := graph.ReachableSet([]Configurable{r.self}, func(c Configurable) ([]Configurable, error) {
+// AllModules returns every configured module in reverse topological order.
+func (r *Root) AllModules() ([]Module, error) {
+	configurables, err := graph.ReverseTopologicalSort([]Configurable{r.self}, func(c Configurable) ([]Configurable, error) {
 		return c.Configurables(), nil
 	})
 	if err != nil {
@@ -264,7 +265,7 @@ func RegisterTypeRef[T Module](b *Base, owner Configurable, ptr *T) error {
 	b.root.refs = append(b.root.refs, refEntry{
 		owner: owner,
 		resolve: func(_ *Root, modules []Module) ([]Module, error) {
-			typeModules := filterByType[T](modules)
+			typeModules := ModulesOfType[T](modules)
 			var zero T
 			if len(typeModules) == 0 {
 				return nil, fmt.Errorf("no module of type %T", zero)
@@ -291,7 +292,7 @@ func RegisterSliceTypeRef[T Module](b *Base, owner Configurable, ptr *[]T) error
 	b.root.refs = append(b.root.refs, refEntry{
 		owner: owner,
 		resolve: func(_ *Root, modules []Module) ([]Module, error) {
-			typeModules := filterByType[T](modules)
+			typeModules := ModulesOfType[T](modules)
 
 			*ptr = typeModules
 
@@ -302,7 +303,8 @@ func RegisterSliceTypeRef[T Module](b *Base, owner Configurable, ptr *[]T) error
 	return nil
 }
 
-func filterByType[T Module](modules []Module) []T {
+// ModulesOfType returns every configured module satisfying T.
+func ModulesOfType[T any](modules []Module) []T {
 	var typeModules []T
 	for _, m := range modules {
 		t, ok := m.(T)

internal/module/registry.go

@@ -10,7 +10,7 @@ import (
 )
 
 //nolint:gochecknoglobals // Required for automatic registration.
-var typeSchemas = make(map[reflect.Type]any)
+var configTypes = make(map[reflect.Type]any)
 
 //nolint:gochecknoglobals // Cached reflect.Type for the marker interfaces.
 var (
@@ -125,9 +125,9 @@ type anySliceSlot interface {
 	sliceSlotType() reflect.Type
 }
 
-// RegisterSchema records the config schema for a Configurable, using a nil prototype (e.g. (*T)(nil)) and a zero-value config struct.
-func RegisterSchema(prototype Configurable, schema any) {
-	typeSchemas[reflect.TypeOf(prototype)] = schema
+// RegisterConfigType records the config type for a Configurable, called with a nil impl (e.g. (*T)(nil)) and a zero-value config struct.
+func RegisterConfigType(impl Configurable, config any) {
+	configTypes[reflect.TypeOf(impl)] = config
 }
 
 // MaxSliceLen returns the longest slice length found anywhere in cfg.
@@ -160,7 +160,7 @@ func MaxSliceLen(rawCfg any) int {
 	return maxLen
 }
 
-type schemaCollector struct {
+type keyCollector struct {
 	cache       map[reflect.Type][]fieldEntry
 	path        map[reflect.Type]struct{}
 	keys        []string
@@ -174,9 +174,9 @@ type fieldEntry struct {
 	slice    bool
 }
 
-// CollectSchemaKeys walks root's tree and returns dotted leaf keys for every reachable schema, with maxSliceLen keys per SliceSlot field.
-func CollectSchemaKeys(root Configurable, maxSliceLen int) ([]string, error) {
-	c := &schemaCollector{
+// ConfigKeys walks root's tree and returns dotted leaf keys for every reachable config type, with maxSliceLen keys per SliceSlot field.
+func ConfigKeys(root Configurable, maxSliceLen int) ([]string, error) {
+	c := &keyCollector{
 		cache:       make(map[reflect.Type][]fieldEntry),
 		path:        make(map[reflect.Type]struct{}),
 		maxSliceLen: maxSliceLen,
@@ -185,30 +185,30 @@ func CollectSchemaKeys(root Configurable, maxSliceLen int) ([]string, error) {
 	return c.keys, c.err
 }
 
-func (c *schemaCollector) walkType(t reflect.Type, prefix string) {
+func (c *keyCollector) walkType(t reflect.Type, prefix string) {
 	if c.err != nil {
 		return
 	}
 
 	_, ok := c.path[t]
 	if ok {
-		c.err = fmt.Errorf("schema cycle: type %v reachable from itself at %q", t, prefix)
+		c.err = fmt.Errorf("config type cycle: type %v reachable from itself at %q", t, prefix)
 		return
 	}
 
-	var schema any
-	schema, ok = typeSchemas[t]
-	if !ok || schema == nil {
+	var configType any
+	configType, ok = configTypes[t]
+	if !ok || configType == nil {
 		return
 	}
 
 	c.path[t] = struct{}{}
-	c.walkFields(schema, prefix)
+	c.walkFields(configType, prefix)
 	delete(c.path, t)
 }
 
-func (c *schemaCollector) walkFields(schema any, prefix string) {
-	for _, f := range c.fieldEntries(schema) {
+func (c *keyCollector) walkFields(configType any, prefix string) {
+	for _, f := range c.fieldEntries(configType) {
 		field := f.name
 		if prefix != "" {
 			field = prefix + "." + f.name
@@ -227,8 +227,8 @@ func (c *schemaCollector) walkFields(schema any, prefix string) {
 	}
 }
 
-func (c *schemaCollector) fieldEntries(schema any) []fieldEntry {
-	t := reflect.TypeOf(schema)
+func (c *keyCollector) fieldEntries(configType any) []fieldEntry {
+	t := reflect.TypeOf(configType)
 	if t.Kind() == reflect.Pointer {
 		t = t.Elem()
 	}
@@ -278,14 +278,14 @@ func (c *schemaCollector) fieldEntries(schema any) []fieldEntry {
 	return entries
 }
 
-func (c *schemaCollector) walkSliceSlot(slotType reflect.Type, prefix string) {
+func (c *keyCollector) walkSliceSlot(slotType reflect.Type, prefix string) {
 	c.keys = append(c.keys, prefix+".id")
 	for i := range c.maxSliceLen {
 		c.walkSingleSlot(slotType, prefix+".items."+strconv.Itoa(i))
 	}
 }
 
-func (c *schemaCollector) walkSingleSlot(slotType reflect.Type, prefix string) {
+func (c *keyCollector) walkSingleSlot(slotType reflect.Type, prefix string) {
 	switch slotType.Kind() {
 	case reflect.Interface:
 		c.walkCategory(slotType, prefix)
@@ -294,9 +294,9 @@ func (c *schemaCollector) walkSingleSlot(slotType reflect.Type, prefix string) {
 	}
 }
 
-func (c *schemaCollector) walkCategory(slotType reflect.Type, prefix string) {
+func (c *keyCollector) walkCategory(slotType reflect.Type, prefix string) {
 	c.keys = append(c.keys, prefix+".type", prefix+".id")
-	for typ := range typeSchemas {
+	for typ := range configTypes {
 		if !typ.Implements(slotType) {
 			continue
 		}