Provide buildpack create command

Implement RFC 212 to provide a more general mechanism to provide
project scaffolding for new buildpacks.

Signed-off-by: Aidan Delaney <adelaney21@bloomberg.net>

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/apex/log v1.9.0
 	github.com/buildpacks/imgutil v0.0.0-20221128174954-533a87656dc4
 	github.com/buildpacks/lifecycle v0.15.3
+	github.com/buildpacks/scafall v0.0.0-20230124113818-e2ea3479ac3d
 	github.com/docker/cli v23.0.0+incompatible
 	github.com/docker/docker v20.10.22+incompatible
 	github.com/docker/go-connections v0.4.0

go.sum

@@ -271,6 +271,8 @@ github.com/buildpacks/imgutil v0.0.0-20221128174954-533a87656dc4 h1:JrC06zJNkuOG
 github.com/buildpacks/imgutil v0.0.0-20221128174954-533a87656dc4/go.mod h1:7XJyKf8MwQfHcsjjA9et24BWN3gE1FztxnN8de54mL0=
 github.com/buildpacks/lifecycle v0.15.3 h1:jjYc0sclsxyCpBQoMkAQKynRrhuRbXXCj9eH7ApUOYQ=
 github.com/buildpacks/lifecycle v0.15.3/go.mod h1:vNhpm82BD9JlzZbFP9JXYt2tMBlIf9EA20VtZ0PkyRE=
+github.com/buildpacks/scafall v0.0.0-20230124113818-e2ea3479ac3d h1:o0CzZvpd9k9bZE5v/vI6AvW4msQneOH6t0fKDNEM+7Y=
+github.com/buildpacks/scafall v0.0.0-20230124113818-e2ea3479ac3d/go.mod h1:0lTi9P0dEYoOx+d6vBoXfNrWYbj5RR1hYLTCyXE4d5E=
 github.com/bwesterb/go-ristretto v1.2.0/go.mod h1:fUIoIZaG73pV5biE2Blr2xEzDoMj7NFEuV9ekS419A0=
 github.com/caarlos0/ctrlc v1.0.0/go.mod h1:CdXpj4rmq0q/1Eb44M9zi2nKB0QraNKuRGYGrrHhcQw=
 github.com/campoy/unique v0.0.0-20180121183637-88950e537e7e/go.mod h1:9IOqJGCPMSc6E5ydlp5NIonxObaeu/Iub/X03EKPVYo=

internal/commands/buildpack.go

@@ -18,6 +18,7 @@ func NewBuildpackCommand(logger logging.Logger, cfg config.Config, client PackCl
 	cmd.AddCommand(BuildpackInspect(logger, cfg, client))
 	cmd.AddCommand(BuildpackPackage(logger, cfg, client, packageConfigReader))
 	cmd.AddCommand(BuildpackNew(logger, client))
+	cmd.AddCommand(BuildpackCreate(logger, client))
 	cmd.AddCommand(BuildpackPull(logger, cfg, client))
 	cmd.AddCommand(BuildpackRegister(logger, cfg, client))
 	cmd.AddCommand(BuildpackYank(logger, cfg, client))

internal/commands/buildpack_create.go

@@ -0,0 +1,70 @@
+package commands
+
+import (
+	"context"
+
+	scafall "github.com/buildpacks/scafall/pkg"
+	"github.com/spf13/cobra"
+
+	"github.com/buildpacks/pack/internal/style"
+	"github.com/buildpacks/pack/pkg/client"
+	"github.com/buildpacks/pack/pkg/logging"
+)
+
+const (
+	CNBTemplates = "https://github.com/buildpacks/templates"
+)
+
+type BuildpackCreateFlags struct {
+	Arguments map[string]string
+	Template  string
+	SubPath   string
+}
+
+type BuildpackCreateCreator interface {
+	CreateBuildpack(ctx context.Context, options client.CreateBuildpackOptions) error
+}
+
+func BuildpackCreate(logger logging.Logger, creator BuildpackCreateCreator) *cobra.Command {
+	flags := BuildpackCreateFlags{}
+	cmd := &cobra.Command{
+		Use:     "create",
+		Short:   "Creates basic scaffolding of a buildpack.",
+		Args:    cobra.MatchAll(cobra.ExactArgs(0)),
+		Example: "pack buildpack create",
+		Long:    "buildpack new generates the basic scaffolding of a buildpack repository.",
+		RunE: logError(logger, func(cmd *cobra.Command, args []string) error {
+			if err := creator.CreateBuildpack(cmd.Context(), client.CreateBuildpackOptions{
+				Template:  flags.Template,
+				SubPath:   flags.SubPath,
+				Arguments: flags.Arguments,
+			}); err != nil {
+				return err
+			}
+
+			logger.Infof("Successfully scaffolded %s", style.Symbol("template"))
+			return nil
+		}),
+	}
+
+	cmd.Flags().StringVarP(&flags.Template, "template", "t", CNBTemplates, "URL of the buildpack template git repository")
+	cmd.Flags().StringVar(&flags.SubPath, "sub-path", "", "directory within template git repository used to generate the buildpack")
+	cmd.Flags().StringToStringVarP(&flags.Arguments, "arg", "a", nil, "arguments to the buildpack template")
+
+	cmd.SetHelpFunc(func(*cobra.Command, []string) {
+		s, err := scafall.NewScafall(flags.Template, scafall.WithSubPath(flags.SubPath))
+		if err != nil {
+			logger.Errorf("unable to get help for template: %s", err)
+		} else {
+			info, args, err := s.TemplateArguments()
+			if err != nil {
+				logger.Errorf("unable to get template arguments for template: %s", err)
+			}
+			logger.Info(info)
+			for _, arg := range args {
+				logger.Infof("\t%s", arg)
+			}
+		}
+	})
+	return cmd
+}

internal/commands/buildpack_create_test.go

@@ -0,0 +1,70 @@
+package commands_test
+
+import (
+	"bytes"
+	"os"
+	"testing"
+
+	"github.com/golang/mock/gomock"
+	"github.com/heroku/color"
+	"github.com/sclevine/spec"
+	"github.com/sclevine/spec/report"
+	"github.com/spf13/cobra"
+
+	"github.com/buildpacks/pack/internal/commands"
+	"github.com/buildpacks/pack/internal/commands/testmocks"
+	"github.com/buildpacks/pack/pkg/client"
+	"github.com/buildpacks/pack/pkg/logging"
+	h "github.com/buildpacks/pack/testhelpers"
+)
+
+func TestBuildpackCreateCommand(t *testing.T) {
+	color.Disable(true)
+	defer color.Disable(false)
+	spec.Run(t, "BuildpackCreateCommand", testBuildpackCreateCommand, spec.Parallel(), spec.Report(report.Terminal{}))
+}
+
+func testBuildpackCreateCommand(t *testing.T, when spec.G, it spec.S) {
+	var (
+		command        *cobra.Command
+		logger         *logging.LogWithWriters
+		outBuf         bytes.Buffer
+		mockController *gomock.Controller
+		mockClient     *testmocks.MockPackClient
+		tmpDir         string
+	)
+
+	it.Before(func() {
+		tmpDir = t.TempDir()
+		logger = logging.NewLogWithWriters(&outBuf, &outBuf)
+		mockController = gomock.NewController(t)
+		mockClient = testmocks.NewMockPackClient(mockController)
+
+		command = commands.BuildpackCreate(logger, mockClient)
+	})
+
+	it.After(func() {
+		os.RemoveAll(tmpDir)
+	})
+
+	when("BuildpackCreate#Execute", func() {
+		it("uses the args to generate artifacts", func() {
+			mockClient.EXPECT().CreateBuildpack(gomock.Any(), client.CreateBuildpackOptions{
+				Template: "testdata",
+				SubPath:  "create",
+				Arguments: map[string]string{
+					"Test": "Quack",
+				},
+			}).Return(nil).MaxTimes(1)
+
+			command.SetArgs([]string{
+				"--template", "testdata",
+				"--sub-path", "create",
+				"--arg", "Test=Quack",
+			})
+
+			err := command.Execute()
+			h.AssertNil(t, err)
+		})
+	})
+}

internal/commands/buildpack_new.go

@@ -25,10 +25,13 @@ type BuildpackNewFlags struct {
 
 // BuildpackCreator creates buildpacks
 type BuildpackCreator interface {
+	// Deprecated: use CreateBuildpack instead
 	NewBuildpack(ctx context.Context, options client.NewBuildpackOptions) error
 }
 
 // BuildpackNew generates the scaffolding of a buildpack
+//
+// Deprecated: Use BuildpackCreate instead
 func BuildpackNew(logger logging.Logger, creator BuildpackCreator) *cobra.Command {
 	var flags BuildpackNewFlags
 	cmd := &cobra.Command{
@@ -38,6 +41,7 @@ func BuildpackNew(logger logging.Logger, creator BuildpackCreator) *cobra.Comman
 		Example: "pack buildpack new sample/my-buildpack",
 		Long:    "buildpack new generates the basic scaffolding of a buildpack repository. It creates a new directory `name` in the current directory (or at `path`, if passed as a flag), and initializes a buildpack.toml, and two executable bash scripts, `bin/detect` and `bin/build`. ",
 		RunE: logError(logger, func(cmd *cobra.Command, args []string) error {
+			logger.Warn("pack buildpack new is deprecated, prefer pack buildpack create instead")
 			id := args[0]
 			idParts := strings.Split(id, "/")
 			dirName := idParts[len(idParts)-1]

internal/commands/commands.go

@@ -23,6 +23,7 @@ type PackClient interface {
 	Rebase(context.Context, client.RebaseOptions) error
 	CreateBuilder(context.Context, client.CreateBuilderOptions) error
 	NewBuildpack(context.Context, client.NewBuildpackOptions) error
+	CreateBuildpack(context.Context, client.CreateBuildpackOptions) error
 	PackageBuildpack(ctx context.Context, opts client.PackageBuildpackOptions) error
 	Build(context.Context, client.BuildOptions) error
 	RegisterBuildpack(context.Context, client.RegisterBuildpackOptions) error

pkg/client/create_buildpack.go

@@ -0,0 +1,34 @@
+package client
+
+import (
+	"context"
+
+	scafall "github.com/buildpacks/scafall/pkg"
+)
+
+type CreateBuildpackOptions struct {
+	// URL of git repository containing the project template
+	Template string
+
+	// Subdirectory within the repository containing the project template
+	SubPath string
+
+	// arguments to provide to the project template
+	Arguments map[string]string
+}
+
+func (c *Client) CreateBuildpack(ctx context.Context, opts CreateBuildpackOptions) error {
+	ops := []scafall.Option{scafall.WithSubPath(opts.SubPath)}
+	if opts.Arguments != nil {
+		ops = append(ops, scafall.WithArguments(opts.Arguments))
+	}
+	s, err := scafall.NewScafall(opts.Template, ops...)
+	if err != nil {
+		return err
+	}
+	err = s.Scaffold()
+	if err != nil {
+		return err
+	}
+	return nil
+}

pkg/client/new_buildpack.go

@@ -47,6 +47,7 @@ type NewBuildpackOptions struct {
 	Stacks []dist.Stack
 }
 
+// Deprecated: use CreateBuildpack instead
 func (c *Client) NewBuildpack(ctx context.Context, opts NewBuildpackOptions) error {
 	err := createBuildpackTOML(opts.Path, opts.ID, opts.Version, opts.API, opts.Stacks, c)
 	if err != nil {