update terragrunt path

cli/commands/stack/action.go

@@ -2,13 +2,20 @@ package stack
 
 import (
 	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/gruntwork-io/terragrunt/config"
+	getter "github.com/hashicorp/go-getter/v2"
 
 	"github.com/gruntwork-io/terragrunt/internal/errors"
 	"github.com/gruntwork-io/terragrunt/options"
 )
 
 const (
-	generate = "generate"
+	generate      = "generate"
+	stackCacheDir = ".terragrunt-stack"
 )
 
 func Run(ctx context.Context, opts *options.TerragruntOptions, subCommand string) error {
@@ -27,6 +34,35 @@ func Run(ctx context.Context, opts *options.TerragruntOptions, subCommand string
 }
 
 func generateStack(ctx context.Context, opts *options.TerragruntOptions) error {
+	//TODO: update stack path
+	opts.TerragrungStackConfigPath = filepath.Join(opts.WorkingDir, "terragrunt.stack.hcl")
+	stackFile, err := config.ReadStackConfigFile(ctx, opts)
+	if err != nil {
+		return err
+	}
+
+	if err := processStackFile(ctx, stackFile); err != nil {
+		return err
+	}
+
+	return nil
+}
+func processStackFile(ctx context.Context, stackFile *config.StackConfigFile) error {
+	if err := os.MkdirAll(stackCacheDir, 0755); err != nil {
+		return errors.New(fmt.Errorf("failed to create base directory: %w", err))
+	}
+
+	for _, unit := range stackFile.Units {
+		destPath := filepath.Join(stackCacheDir, unit.Path)
+
+		if err := os.MkdirAll(destPath, 0755); err != nil {
+			return errors.New(fmt.Errorf("failed to create destination directory '%s': %w", destPath, err))
+		}
+
+		if _, err := getter.GetAny(ctx, unit.Source, destPath); err != nil {
+			return errors.New(fmt.Errorf("failed to fetch source '%s' to destination '%s': %w", unit.Source, destPath, err))
+		}
+	}
 
 	return nil
 }