feat(pack): add support for scaffolding new extensions

internal/commands/commands.go

@@ -25,6 +25,7 @@ type PackClient interface {
 	NewBuildpack(context.Context, client.NewBuildpackOptions) error
 	PackageBuildpack(ctx context.Context, opts client.PackageBuildpackOptions) error
 	PackageExtension(ctx context.Context, opts client.PackageBuildpackOptions) error
+	NewExtension(ctx context.Context, options client.NewExtensionOptions) error
 	Build(context.Context, client.BuildOptions) error
 	RegisterBuildpack(context.Context, client.RegisterBuildpackOptions) error
 	YankBuildpack(client.YankBuildpackOptions) error

internal/commands/extension.go

@@ -19,7 +19,7 @@ func NewExtensionCommand(logger logging.Logger, cfg config.Config, client PackCl
 	// client and packageConfigReader to be passed later on
 	cmd.AddCommand(ExtensionPackage(logger, cfg, client, packageConfigReader))
 	// client to be passed later on
-	cmd.AddCommand(ExtensionNew(logger))
+	cmd.AddCommand(ExtensionNew(logger, client))
 	cmd.AddCommand(ExtensionPull(logger, cfg, client))
 	cmd.AddCommand(ExtensionRegister(logger, cfg, client))
 	cmd.AddCommand(ExtensionYank(logger, cfg, client))

internal/commands/extension_new.go

@@ -1,8 +1,19 @@
 package commands
 
 import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
 	"github.com/spf13/cobra"
 
+	"github.com/buildpacks/pack/internal/style"
+	"github.com/buildpacks/pack/internal/target"
+	"github.com/buildpacks/pack/pkg/client"
+	"github.com/buildpacks/pack/pkg/dist"
 	"github.com/buildpacks/pack/pkg/logging"
 )
 
@@ -11,25 +22,78 @@
 	API     string
 	Path    string
 	Stacks  []string
+	Targets []string
 	Version string
 }
 
 // extensioncreator type to be added here and argument also to be added in the function
+type ExtensionCreator interface {
+	NewExtension(ctx context.Context, options client.NewExtensionOptions) error
+}
 
 // ExtensionNew generates the scaffolding of an extension
-func ExtensionNew(logger logging.Logger) *cobra.Command {
+func ExtensionNew(logger logging.Logger, creator ExtensionCreator) *cobra.Command {
+	var flags ExtensionNewFlags
 	cmd := &cobra.Command{
 		Use:     "new <id>",
 		Short:   "Creates basic scaffolding of an extension",
 		Args:    cobra.MatchAll(cobra.ExactArgs(1), cobra.OnlyValidArgs),
 		Example: "pack extension new <example-extension>",
 		RunE: logError(logger, func(cmd *cobra.Command, args []string) error {
-			// logic will go here
+			id := args[0]
+			idParts := strings.Split(id, "/")
+			dirName := idParts[len(idParts)-1]
+
+			var path string
+			if len(flags.Path) == 0 {
+				cwd, err := os.Getwd()
+				if err != nil {
+					return err
+				}
+				path = filepath.Join(cwd, dirName)
+			} else {
+				path = flags.Path
+			}
+
+			_, err := os.Stat(path)
+			if !os.IsNotExist(err) {
+				return fmt.Errorf("directory %s exists", style.Symbol(path))
+			}
+
+			var targets []dist.Target
+			if len(flags.Targets) == 0 && len(flags.Stacks) == 0 {
+				targets = []dist.Target{{
+					OS:   runtime.GOOS,
+					Arch: runtime.GOARCH,
+				}}
+			} else {
+				if targets, err = target.ParseTargets(flags.Targets, logger); err != nil {
+					return err
+				}
+			}
+
+			if err := creator.NewExtension(cmd.Context(), client.NewExtensionOptions{
+				API:     flags.API,
+				ID:      id,
+				Path:    path,
+				Targets: targets,
+				Version: flags.Version,
+			}); err != nil {
+				return err
+			}
+
+			logger.Infof("Successfully created %s", style.Symbol(id))
 			return nil
 		}),
 	}
-
-	// flags will go here
+	cmd.Flags().StringVarP(&flags.API, "api", "a", "0.9", "Buildpack API compatibility of the generated extension")
+	cmd.Flags().StringVarP(&flags.Path, "path", "p", "", "Path to generate the extension")
+	cmd.Flags().StringVarP(&flags.Version, "version", "V", "1.0.0", "Version of the generated extension")
+	cmd.Flags().StringSliceVarP(&flags.Targets, "targets", "t", nil,
+		`A list of platforms to target; these recorded in extension.toml. One can provide targets in the format [os][/arch][/arch-variant]:[distroname@osversion];[distroname@osversion]	
+	- Example:  '--targets "linux/amd64" --targets "linux/arm64"'
+	- Example (distribution version): '--targets "windows/amd64:[email protected]"'
+	- Example (architecture with distributed versions): '--targets "linux/arm/v6:[email protected]"  --targets "linux/arm/v6:[email protected]"'	`)
 
 	AddHelpFlag(cmd, "new")
 	return cmd

internal/commands/extension_new_test.go

@@ -0,0 +1,180 @@
+package commands_test
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/buildpacks/pack/pkg/client"
+	"github.com/buildpacks/pack/pkg/dist"
+	"github.com/buildpacks/pack/pkg/logging"
+
+	"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"
+	h "github.com/buildpacks/pack/testhelpers"
+)
+
+func TestExtensionNewCommand(t *testing.T) {
+	color.Disable(true)
+	defer color.Disable(false)
+	spec.Run(t, "ExtensionNewCommand", testExtensionNewCommand, spec.Parallel(), spec.Report(report.Terminal{}))
+}
+
+func testExtensionNewCommand(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
+	)
+	targets := []dist.Target{{
+		OS:   runtime.GOOS,
+		Arch: runtime.GOARCH,
+	}}
+
+	it.Before(func() {
+		var err error
+		tmpDir, err = os.MkdirTemp("", "build-test")
+		h.AssertNil(t, err)
+
+		logger = logging.NewLogWithWriters(&outBuf, &outBuf)
+		mockController = gomock.NewController(t)
+		mockClient = testmocks.NewMockPackClient(mockController)
+
+		command = commands.ExtensionNew(logger, mockClient)
+	})
+
+	it.After(func() {
+		os.RemoveAll(tmpDir)
+	})
+
+	when("ExtensionNew#Execute", func() {
+		it("uses the args to generate artifacts", func() {
+			mockClient.EXPECT().NewExtension(gomock.Any(), client.NewExtensionOptions{
+				API:     "0.9",
+				ID:      "example/some-cnb",
+				Path:    filepath.Join(tmpDir, "some-cnb"),
+				Version: "1.0.0",
+				Targets: targets,
+			}).Return(nil).MaxTimes(1)
+
+			path := filepath.Join(tmpDir, "some-cnb")
+			command.SetArgs([]string{"--path", path, "example/some-cnb"})
+
+			err := command.Execute()
+			h.AssertNil(t, err)
+		})
+
+		it("stops if the directory already exists", func() {
+			err := os.MkdirAll(tmpDir, 0600)
+			h.AssertNil(t, err)
+
+			command.SetArgs([]string{"--path", tmpDir, "example/some-cnb"})
+			err = command.Execute()
+			h.AssertNotNil(t, err)
+			h.AssertContains(t, outBuf.String(), "ERROR: directory")
+		})
+
+		when("target flag is specified, ", func() {
+			it("it uses target to generate artifacts", func() {
+				mockClient.EXPECT().NewExtension(gomock.Any(), client.NewExtensionOptions{
+					API:     "0.9",
+					ID:      "example/targets",
+					Path:    filepath.Join(tmpDir, "targets"),
+					Version: "1.0.0",
+					Targets: []dist.Target{{
+						OS:          "linux",
+						Arch:        "arm",
+						ArchVariant: "v6",
+						Distributions: []dist.Distribution{{
+							Name:     "ubuntu",
+							Versions: []string{"14.04", "16.04"},
+						}},
+					}},
+				}).Return(nil).MaxTimes(1)
+
+				path := filepath.Join(tmpDir, "targets")
+				command.SetArgs([]string{"--path", path, "example/targets", "--targets", "linux/arm/v6:[email protected]@16.04"})
+
+				err := command.Execute()
+				h.AssertNil(t, err)
+			})
+			it("it should show error when invalid [os]/[arch] passed", func() {
+				mockClient.EXPECT().NewExtension(gomock.Any(), client.NewExtensionOptions{
+					API:     "0.9",
+					ID:      "example/targets",
+					Path:    filepath.Join(tmpDir, "targets"),
+					Version: "1.0.0",
+					Targets: []dist.Target{{
+						OS:          "os",
+						Arch:        "arm",
+						ArchVariant: "v6",
+						Distributions: []dist.Distribution{{
+							Name:     "ubuntu",
+							Versions: []string{"14.04", "16.04"},
+						}},
+					}},
+				}).Return(nil).MaxTimes(1)
+
+				path := filepath.Join(tmpDir, "targets")
+				command.SetArgs([]string{"--path", path, "example/targets", "--targets", "os/arm/v6:[email protected]@16.04"})
+
+				err := command.Execute()
+				h.AssertNotNil(t, err)
+			})
+			when("it should", func() {
+				it("support format [os][/arch][/variant]:[name@version@version2];[some-name@version@version2]", func() {
+					mockClient.EXPECT().NewExtension(gomock.Any(), client.NewExtensionOptions{
+						API:     "0.9",
+						ID:      "example/targets",
+						Path:    filepath.Join(tmpDir, "targets"),
+						Version: "1.0.0",
+						Targets: []dist.Target{
+							{
+								OS:          "linux",
+								Arch:        "arm",
+								ArchVariant: "v6",
+								Distributions: []dist.Distribution{
+									{
+										Name:     "ubuntu",
+										Versions: []string{"14.04", "16.04"},
+									},
+									{
+										Name:     "debian",
+										Versions: []string{"8.10", "10.9"},
+									},
+								},
+							},
+							{
+								OS:   "windows",
+								Arch: "amd64",
+								Distributions: []dist.Distribution{
+									{
+										Name:     "windows-nano",
+										Versions: []string{"10.0.19041.1415"},
+									},
+								},
+							},
+						},
+					}).Return(nil).MaxTimes(1)
+
+					path := filepath.Join(tmpDir, "targets")
+					command.SetArgs([]string{"--path", path, "example/targets", "--targets", "linux/arm/v6:[email protected]@16.04;[email protected]@10.9", "-t", "windows/amd64:[email protected]"})
+
+					err := command.Execute()
+					h.AssertNil(t, err)
+				})
+			})
+		})
+	})
+}