feat: templating tool for direct controller builder

dev/tools/controllerbuilder/cmd/root.go

@@ -0,0 +1,50 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/GoogleCloudPlatform/k8s-config-connector/dev/tools/controllerbuilder/scaffold"
+	"github.com/GoogleCloudPlatform/k8s-config-connector/dev/tools/controllerbuilder/template"
+	"github.com/spf13/cobra"
+)
+
+var (
+	serviceName string
+	// TODO: Resource and kind name should be the same. Validation the uppercase/lowercase.
+	kind       string
+	apiVersion string
+
+	addCmd = &cobra.Command{
+		Use:   "add",
+		Short: "add direct controller",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			// TODO(check kcc root)
+			cArgs := &template.ControllerArgs{
+				Service:     serviceName,
+				Version:     apiVersion,
+				Kind:        kind,
+				KindToLower: strings.ToLower(kind),
+			}
+			path, err := scaffold.BuildControllerPath(serviceName, kind)
+			if err != nil {
+				return err
+			}
+			return scaffold.Scaffold(path, cArgs)
+		},
+	}
+)
+
+func init() {
+	addCmd.PersistentFlags().StringVarP(&apiVersion, "version", "v", "v1alpha1", "the KRM API version. used to import the KRM API")
+	addCmd.PersistentFlags().StringVarP(&serviceName, "service", "s", "", "the GCP service name")
+	addCmd.PersistentFlags().StringVarP(&kind, "resourceInKind", "r", "", "the GCP resource name under the GCP service. should be in camel case ")
+}
+
+func Execute() {
+	if err := addCmd.Execute(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}

dev/tools/controllerbuilder/go.mod

@@ -0,0 +1,18 @@
+module github.com/GoogleCloudPlatform/k8s-config-connector/dev/tools/controllerbuilder
+
+go 1.23
+
+require (
+	github.com/fatih/color v1.17.0
+	github.com/spf13/cobra v1.8.0
+	golang.org/x/tools v0.21.0
+)
+
+require (
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	golang.org/x/mod v0.17.0 // indirect
+	golang.org/x/sys v0.20.0 // indirect
+)

dev/tools/controllerbuilder/main.go

@@ -0,0 +1,7 @@
+package main
+
+import "github.com/GoogleCloudPlatform/k8s-config-connector/dev/tools/controllerbuilder/cmd"
+
+func main() {
+	cmd.Execute()
+}

dev/tools/controllerbuilder/scaffold/controller.go

@@ -0,0 +1,88 @@
+package scaffold
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/template"
+
+	ccTemplate "github.com/GoogleCloudPlatform/k8s-config-connector/dev/tools/controllerbuilder/template"
+	"github.com/fatih/color"
+	"golang.org/x/tools/imports"
+)
+
+const (
+	currRelPath             = "dev/tools/controllerbuilder"
+	directControllerRelPath = "pkg/controller/direct"
+)
+
+func Scaffold(path string, cArgs *ccTemplate.ControllerArgs) error {
+	tmpl, err := template.New(cArgs.Kind).Parse(ccTemplate.ControllerTemplate)
+	if err != nil {
+		return fmt.Errorf("parse controller template: %s", err)
+	}
+	// Apply the `service` and `resource` args to the controller template
+	out := &bytes.Buffer{}
+	if err := tmpl.Execute(out, cArgs); err != nil {
+		return err
+	}
+	// Write the generated controller.go to  pkg/controller/direct/<service>/<resource>_controller.go
+	if err := WriteToFile(path, out.Bytes()); err != nil {
+		return err
+	}
+	// Format and adjust the go imports in the generated controller file.
+	if err := FormatImports(path, out.Bytes()); err != nil {
+		return err
+	}
+	color.HiGreen("New controller %s\nEnjoy it!\n", path)
+	return nil
+}
+
+func BuildControllerPath(service, kind string) (string, error) {
+	pwd, err := os.Getwd()
+	if err != nil {
+		return "", fmt.Errorf("get current working directory: %w", err)
+	}
+	abs, err := filepath.Abs(pwd)
+	if err != nil {
+		return "", fmt.Errorf("get absolute path %s: %w", pwd, err)
+	}
+	seg := strings.Split(abs, currRelPath)
+	controllerDir := filepath.Join(seg[0], directControllerRelPath, service)
+	err = os.MkdirAll(controllerDir, os.ModePerm)
+	if err != nil {
+		return "", fmt.Errorf("create controller directory %s: %w", controllerDir, err)
+	}
+	controllerFilePath := filepath.Join(controllerDir, strings.ToLower(kind)+"_controller.go")
+	if _, err := os.Stat(controllerFilePath); err == nil {
+		return "", fmt.Errorf("controller file %s may already exist: %w", controllerFilePath, err)
+	}
+	return controllerFilePath, nil
+}
+
+func FormatImports(path string, out []byte) error {
+	importOps := &imports.Options{
+		Comments:  true,
+		AllErrors: true,
+		Fragment:  true}
+	formatedOut, err := imports.Process(path, out, importOps)
+	if err != nil {
+		return fmt.Errorf("format controller file %s: %w", path, err)
+	}
+	return WriteToFile(path, formatedOut)
+}
+
+func WriteToFile(path string, out []byte) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return fmt.Errorf("create controller file %s: %w", path, err)
+	}
+	err = os.WriteFile(path, out, 0644)
+	if err != nil {
+		return fmt.Errorf("write controller file %s: %w", path, err)
+	}
+	defer f.Close()
+	return nil
+}