Refactor app/pkg init logic (#913)

* Scope logic dealing with vendir.yml to VendirConfig

* Refactor how Fetch is configured. Move build scoped fucntions to build.

* Split VendirStep into VendirRunner and VendirConfigBuilder. Remove deadcode

* Refactor git step. Remove deadcode.

* Refactor GithubStep

* Remove unused create step and refactor necessarily in app init

* Refactor GitStep

* Dedup app init logic. configureAppBuild => getAppBuildName

* Refactor TemplateStep

* Remove step interface and move Build interface

* Refactoring package init

* Add missing deffered cleanup

* Remove file_utils. Use builins instead

* Add check while running vendir sync to handle local directory case

* Merge VendirCOnfiguration into FetchConfiguation

* Move PackageBuild and AppBuild to buildconfigs

* Move vendir config and related objects to sources package

* Move init command files out of a separate package

* Remove dependency of annotation for storing fetch mode

* Moving constants to appropriate locations

* Returning a non-pointer value from GetExport as it is always dereferenced. Removing stale comments

* Stricter checks before running vendir sync. Making not exists check on files cleaner

* Move source specific configuration to source.go. fetch.go => source.go. Refactoring init files

* Remove unnecessary dependency on carvel-kapp-controller/.../exec package

* Use vendirConfig.Contents while configuring package build instead of passing contents down the function tree

* Move logic for initialising deploy section to build interface. Remove duplicate dependencies

* TemplateConfiguration => Template. Othere refactoring.

Author: 100mik

cli/pkg/kctrl/cmd/app/init.go

@@ -0,0 +1,202 @@
+// Copyright 2022 VMware, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+package app
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/cppforlife/go-cli-ui/ui"
+	"github.com/spf13/cobra"
+	cmdcore "github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd/core"
+	buildconfigs "github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/local/buildconfigs"
+	sources "github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/local/sources"
+	"github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/logger"
+	kcv1alpha1 "github.com/vmware-tanzu/carvel-kapp-controller/pkg/apis/kappctrl/v1alpha1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"sigs.k8s.io/yaml"
+)
+
+const (
+	AppFileName = "app.yml"
+	//TODO: Where should this constant reside, it is also used by package init
+	LocalFetchAnnotationKey = "kctrl.carvel.dev/local-fetch-0"
+)
+
+type InitOptions struct {
+	ui          cmdcore.AuthoringUI
+	depsFactory cmdcore.DepsFactory
+	logger      logger.Logger
+	chdir       string
+}
+
+func NewInitOptions(ui ui.UI, depsFactory cmdcore.DepsFactory, logger logger.Logger) *InitOptions {
+	return &InitOptions{ui: cmdcore.NewAuthoringUIImpl(ui), depsFactory: depsFactory, logger: logger}
+}
+
+func NewInitCmd(o *InitOptions) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "init",
+		Short: "Initialize App",
+		RunE:  func(_ *cobra.Command, _ []string) error { return o.Run() },
+	}
+
+	cmd.Flags().StringVar(&o.chdir, "chdir", "", "Working directory with app-build and other config")
+	return cmd
+}
+
+func (o *InitOptions) Run() error {
+	if o.chdir != "" {
+		err := os.Chdir(o.chdir)
+		if err != nil {
+			return err
+		}
+	}
+
+	o.ui.PrintHeaderText("\nPre-requisite")
+	o.ui.PrintInformationalText("Welcome! Before we start on the app creation journey, please ensure the following pre-requites are met:\n* The Carvel suite of tools are installed. Do get familiar with the following Carvel tools: ytt, imgpkg, vendir, and kbld.\n* You have access to an OCI registry, and authenticated locally so that images can be pushed. e.g. docker login <REGISTRY URL>\n")
+
+	appBuild, err := buildconfigs.NewAppBuild()
+	if err != nil {
+		return err
+	}
+
+	err = o.getAppBuildName(appBuild)
+	if err != nil {
+		return err
+	}
+
+	err = o.writeAppFile(appBuild)
+	if err != nil {
+		return err
+	}
+
+	fetchMode, err := sources.NewSource(o.ui, appBuild).Configure()
+	if err != nil {
+		return err
+	}
+
+	err = sources.NewVendirRunner(o.ui).Sync(fetchMode)
+	if err != nil {
+		return err
+	}
+
+	err = sources.NewTemplate(o.ui, appBuild).Configure(fetchMode)
+	if err != nil {
+		return err
+	}
+
+	appBuild.InitializeOrKeepDeploySection()
+	buildconfigs.ConfigureExportSection(appBuild, fetchMode == sources.LocalDirectory, sources.VendirSyncDirectory)
+	err = appBuild.Save()
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (o *InitOptions) getAppBuildName(appBuild *buildconfigs.AppBuild) error {
+	o.ui.PrintHeaderText("\nBasic Information")
+	wd, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	defaultAppName := filepath.Base(wd)
+	appBuildObjectMeta := appBuild.GetObjectMeta()
+	if appBuildObjectMeta == nil {
+		appBuildObjectMeta = &metav1.ObjectMeta{}
+	}
+	if len(appBuildObjectMeta.Name) != 0 {
+		defaultAppName = appBuildObjectMeta.Name
+	}
+
+	textOpts := ui.TextOpts{
+		Label:        "Enter the app name",
+		Default:      defaultAppName,
+		ValidateFunc: nil,
+	}
+	appName, err := o.ui.AskForText(textOpts)
+	if err != nil {
+		return err
+	}
+	appBuildObjectMeta.Name = appName
+	appBuild.SetObjectMeta(appBuildObjectMeta)
+
+	err = appBuild.Save()
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (o *InitOptions) writeAppFile(appBuild *buildconfigs.AppBuild) error {
+	appConfig, err := o.generateApp(appBuild)
+	if err != nil {
+		return err
+	}
+
+	appContent, err := yaml.Marshal(appConfig)
+	if err != nil {
+		return err
+	}
+	err = os.WriteFile(AppFileName, appContent, os.ModePerm)
+	if err != nil {
+		return err
+	}
+	o.ui.PrintHeaderText("\nOutput")
+	o.ui.PrintInformationalText("Successfully updated app-build.yml\n")
+	o.ui.PrintInformationalText("Successfully updated app.yml\n")
+	o.ui.PrintHeaderText("\n**Next steps**")
+	o.ui.PrintInformationalText("Created files can be consumed in following ways:\n1. Optionally, use 'kctrl dev deploy' to iterate on the app and deploy locally.\n2. Use 'kctrl app release' to release the app.\n")
+	return nil
+}
+
+func (o *InitOptions) generateApp(appBuild *buildconfigs.AppBuild) (kcv1alpha1.App, error) {
+	var app kcv1alpha1.App
+	_, err := os.Stat(AppFileName)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return o.createAppFromAppBuild(appBuild), nil
+		}
+		return kcv1alpha1.App{}, err
+	}
+
+	data, err := os.ReadFile(AppFileName)
+	if err != nil {
+		return kcv1alpha1.App{}, err
+	}
+	err = yaml.Unmarshal(data, &app)
+	if err != nil {
+		return kcv1alpha1.App{}, err
+	}
+
+	return app, nil
+
+}
+
+func (o *InitOptions) createAppFromAppBuild(appBuild *buildconfigs.AppBuild) kcv1alpha1.App {
+	appName := "microservices-demo"
+	serviceAccountName := fmt.Sprintf("%s-sa", appName)
+	appAnnotation := map[string]string{
+		LocalFetchAnnotationKey: ".",
+	}
+	appTemplateSection := appBuild.GetAppSpec().Template
+	appDeploySection := appBuild.GetAppSpec().Deploy
+	return kcv1alpha1.App{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "kappctrl.k14s.io/v1alpha1",
+			Kind:       "App",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:        appName,
+			Annotations: appAnnotation,
+		},
+		Spec: kcv1alpha1.AppSpec{
+			ServiceAccountName: serviceAccountName,
+			Template:           appTemplateSection,
+			Deploy:             appDeploySection,
+		},
+	}
+}