✨ Add feature gate marker support

cmd/controller-gen/main.go

@@ -65,10 +65,11 @@ var (
 	// - output:<generator>:<form> (per-generator output)
 	// - output:<form> (default output)
 	allOutputRules = map[string]genall.OutputRule{
-		"dir":       genall.OutputToDirectory(""),
-		"none":      genall.OutputToNothing,
-		"stdout":    genall.OutputToStdout,
-		"artifacts": genall.OutputArtifacts{},
+		"dir":             genall.OutputToDirectory(""),
+		"none":            genall.OutputToNothing,
+		"stdout":          genall.OutputToStdout,
+		"artifacts":       genall.OutputArtifacts{},
+		"featuregate-dir": genall.OutputToFeatureGateDirectories{},
 	}
 
 	// optionsRegistry contains all the marker definitions used to process command line options
@@ -209,6 +210,12 @@ func main() {
 		return helpForLevels(c.OutOrStdout(), c.OutOrStderr(), helpLevel, optionsRegistry, help.SortByOption)
 	})
 
+	// Add workflow command for advanced multi-gate, multi-output generation patterns
+	if len(os.Args) > 1 && os.Args[1] == "workflow" {
+		workflowCmd := NewWorkflowCommand()
+		cmd.AddCommand(workflowCmd)
+	}
+
 	if err := cmd.Execute(); err != nil {
 		var errNoUsage noUsageError
 		if !errors.As(err, &errNoUsage) {

cmd/controller-gen/workflow.go

@@ -0,0 +1,267 @@
+/*
+Copyright 2025.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"sigs.k8s.io/controller-tools/pkg/featuregate"
+	"sigs.k8s.io/controller-tools/pkg/genall"
+)
+
+// NewWorkflowCommand provides advanced CLI workflows for multi-gate, multi-output generation
+func NewWorkflowCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "workflow",
+		Short: "Advanced workflows for multi-gate, multi-output generation",
+		Long: `Advanced workflows for generating multiple CRD variants with different feature gate combinations.
+
+This enables developers to:
+- Generate CRDs for multiple feature gate combinations in a single command
+- Create progressive rollout scenarios
+- Test feature gate matrix combinations
+
+Examples:
+  # Generate CRDs for all feature gate combinations
+  controller-gen workflow matrix --gates=alpha,beta --base-path=./output
+
+  # Generate CRDs for progressive rollout
+  controller-gen workflow progressive --gates=alpha,beta,gamma --base-path=./output`,
+	}
+
+	cmd.AddCommand(NewMatrixCommand())
+	cmd.AddCommand(NewProgressiveCommand())
+
+	return cmd
+}
+
+// createWorkflowCommand creates a workflow command with common flags and validation
+func createWorkflowCommand(use, short, long string, runFunc func([]string, string, []string) error) *cobra.Command {
+	var gates []string
+	var basePath string
+	var paths []string
+
+	cmd := &cobra.Command{
+		Use:   use,
+		Short: short,
+		Long:  long,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(gates) == 0 {
+				return fmt.Errorf("at least one feature gate must be specified")
+			}
+			if basePath == "" {
+				return fmt.Errorf("base path must be specified")
+			}
+			if len(paths) == 0 {
+				paths = []string{"./..."}
+			}
+
+			return runFunc(gates, basePath, paths)
+		},
+	}
+
+	cmd.Flags().StringSliceVar(&gates, "gates", nil, "Feature gates to generate combinations for")
+	cmd.Flags().StringVar(&basePath, "base-path", "", "Base output directory")
+	cmd.Flags().StringSliceVar(&paths, "paths", []string{"./..."}, "Go package paths to process")
+
+	_ = cmd.MarkFlagRequired("gates")
+	_ = cmd.MarkFlagRequired("base-path")
+
+	return cmd
+}
+
+// NewMatrixCommand generates CRDs for all possible feature gate combinations
+func NewMatrixCommand() *cobra.Command {
+	return createWorkflowCommand(
+		"matrix",
+		"Generate CRDs for all possible feature gate combinations",
+		`Generate CRDs for all possible combinations of the specified feature gates.
+
+This will create directories for each combination:
+- no_gates/ (all gates disabled)
+- alpha/ (only alpha enabled)  
+- beta/ (only beta enabled)
+- alpha_beta/ (both alpha and beta enabled)
+- etc.
+
+This is useful for testing and packaging different feature variants.`,
+		generateMatrix,
+	)
+}
+
+// NewProgressiveCommand generates CRDs for progressive feature rollout
+func NewProgressiveCommand() *cobra.Command {
+	return createWorkflowCommand(
+		"progressive",
+		"Generate CRDs for progressive feature rollout",
+		`Generate CRDs for progressive feature rollout scenarios:
+
+- stage_0/ (stable features only)
+- stage_1/ (stable + first gate)
+- stage_2/ (stable + first two gates)  
+- stage_N/ (stable + all gates)
+
+This enables gradual feature introduction in production environments.`,
+		generateProgressive,
+	)
+}
+
+// generateMatrix generates all possible feature gate combinations
+func generateMatrix(gates []string, basePath string, paths []string) error {
+	// Generate all 2^n combinations
+	n := len(gates)
+	totalCombinations := 1 << n
+
+	fmt.Printf("Generating %d feature gate combinations for gates: %v\n", totalCombinations, gates)
+
+	for i := 0; i < totalCombinations; i++ {
+		var enabledGates []string
+		var gateSettings []string
+
+		for j, gate := range gates {
+			if (i>>j)&1 == 1 {
+				enabledGates = append(enabledGates, gate)
+				gateSettings = append(gateSettings, fmt.Sprintf("%s=true", gate))
+			} else {
+				gateSettings = append(gateSettings, fmt.Sprintf("%s=false", gate))
+			}
+		}
+
+		combination := strings.Join(gateSettings, ",")
+		outputDir := getOutputDirectory(enabledGates)
+
+		err := runGenerationForCombination(combination, filepath.Join(basePath, outputDir), paths)
+		if err != nil {
+			return fmt.Errorf("failed to generate for combination %s: %w", combination, err)
+		}
+	}
+
+	fmt.Printf("Successfully generated all %d combinations in %s\n", totalCombinations, basePath)
+	return nil
+}
+
+// generateProgressive generates progressive rollout configurations
+func generateProgressive(gates []string, basePath string, paths []string) error {
+	stages := len(gates) + 1
+
+	fmt.Printf("Generating %d progressive stages for gates: %v\n", stages, gates)
+
+	// Stage 0: all gates disabled
+	stage0Settings := make([]string, len(gates))
+	for i, gate := range gates {
+		stage0Settings[i] = fmt.Sprintf("%s=false", gate)
+	}
+
+	err := runGenerationForCombination(
+		strings.Join(stage0Settings, ","),
+		filepath.Join(basePath, "stage_0"),
+		paths,
+	)
+	if err != nil {
+		return fmt.Errorf("failed to generate stage 0: %w", err)
+	}
+
+	// Progressive stages: enable one more gate at each stage
+	for i := 1; i <= len(gates); i++ {
+		var stageSettings []string
+		for j, gate := range gates {
+			if j < i {
+				stageSettings = append(stageSettings, fmt.Sprintf("%s=true", gate))
+			} else {
+				stageSettings = append(stageSettings, fmt.Sprintf("%s=false", gate))
+			}
+		}
+
+		err := runGenerationForCombination(
+			strings.Join(stageSettings, ","),
+			filepath.Join(basePath, fmt.Sprintf("stage_%d", i)),
+			paths,
+		)
+		if err != nil {
+			return fmt.Errorf("failed to generate stage %d: %w", i, err)
+		}
+	}
+
+	fmt.Printf("Successfully generated all %d progressive stages in %s\n", stages, basePath)
+	return nil
+}
+
+// getOutputDirectory determines the output directory name based on enabled gates
+func getOutputDirectory(enabledGates []string) string {
+	if len(enabledGates) == 0 {
+		return "no_gates"
+	}
+
+	// Sort gates for consistent naming
+	for i := 0; i < len(enabledGates)-1; i++ {
+		for j := 0; j < len(enabledGates)-i-1; j++ {
+			if enabledGates[j] > enabledGates[j+1] {
+				enabledGates[j], enabledGates[j+1] = enabledGates[j+1], enabledGates[j]
+			}
+		}
+	}
+
+	return strings.Join(enabledGates, "_")
+}
+
+// runGenerationForCombination runs controller-gen for a specific feature gate combination
+func runGenerationForCombination(featureGates string, outputPath string, paths []string) error {
+	// Create output directory
+	if err := os.MkdirAll(outputPath, 0755); err != nil {
+		return fmt.Errorf("failed to create output directory %s: %w", outputPath, err)
+	}
+
+	fmt.Printf("  Generating: %s -> %s\n", featureGates, outputPath)
+
+	// Parse feature gates to validate them
+	_, err := featuregate.ParseFeatureGates(featureGates)
+	if err != nil {
+		return fmt.Errorf("invalid feature gates %s: %w", featureGates, err)
+	}
+
+	// Create a runtime configuration for this combination
+	args := []string{
+		"crd",
+		fmt.Sprintf("crd:featureGates=%s", featureGates),
+		fmt.Sprintf("output:crd:dir=%s", outputPath),
+	}
+
+	// Add paths
+	for _, path := range paths {
+		args = append(args, fmt.Sprintf("paths=%s", path))
+	}
+
+	// Use the existing optionsRegistry and run generation
+	rt, err := genall.FromOptions(optionsRegistry, args)
+	if err != nil {
+		return fmt.Errorf("failed to create runtime for combination %s: %w", featureGates, err)
+	}
+
+	if len(rt.Generators) == 0 {
+		return fmt.Errorf("no generators specified for combination %s", featureGates)
+	}
+
+	if hadErrs := rt.Run(); hadErrs {
+		return fmt.Errorf("generation failed for combination %s", featureGates)
+	}
+
+	return nil
+}