Merge pull request cli#3761 from cli/command-extensions

Experimental command extensions support

Author: mislav

cmd/gh/main.go

@@ -21,6 +21,7 @@ import (
 	"github.com/cli/cli/internal/run"
 	"github.com/cli/cli/internal/update"
 	"github.com/cli/cli/pkg/cmd/alias/expand"
+	"github.com/cli/cli/pkg/cmd/extensions"
 	"github.com/cli/cli/pkg/cmd/factory"
 	"github.com/cli/cli/pkg/cmd/root"
 	"github.com/cli/cli/pkg/cmdutil"
@@ -140,15 +141,27 @@ func mainRun() exitCode {
 
 			err = preparedCmd.Run()
 			if err != nil {
-				if ee, ok := err.(*exec.ExitError); ok {
-					return exitCode(ee.ExitCode())
+				var execError *exec.ExitError
+				if errors.As(err, &execError) {
+					return exitCode(execError.ExitCode())
 				}
-
 				fmt.Fprintf(stderr, "failed to run external command: %s", err)
 				return exitError
 			}
 
 			return exitOK
+		} else if c, _, err := rootCmd.Traverse(expandedArgs); err == nil && c == rootCmd && len(expandedArgs) > 0 {
+			extensionManager := extensions.NewManager()
+			if found, err := extensionManager.Dispatch(expandedArgs, os.Stdin, os.Stdout, os.Stderr); err != nil {
+				var execError *exec.ExitError
+				if errors.As(err, &execError) {
+					return exitCode(execError.ExitCode())
+				}
+				fmt.Fprintf(stderr, "failed to run extension: %s", err)
+				return exitError
+			} else if found {
+				return exitOK
+			}
 		}
 	}
 

pkg/cmd/extensions/command.go

@@ -0,0 +1,77 @@
+package extensions
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/cli/cli/internal/ghrepo"
+	"github.com/cli/cli/pkg/cmdutil"
+	"github.com/cli/cli/pkg/iostreams"
+	"github.com/spf13/cobra"
+)
+
+func NewCmdExtensions(io *iostreams.IOStreams) *cobra.Command {
+	m := NewManager()
+
+	extCmd := cobra.Command{
+		Use:   "extensions",
+		Short: "Manage gh extensions",
+	}
+
+	extCmd.AddCommand(
+		&cobra.Command{
+			Use:   "list",
+			Short: "List installed extension commands",
+			Args:  cobra.NoArgs,
+			RunE: func(cmd *cobra.Command, args []string) error {
+				cmds := m.List()
+				if len(cmds) == 0 {
+					return errors.New("no extensions installed")
+				}
+				for _, c := range cmds {
+					name := filepath.Base(c)
+					parts := strings.SplitN(name, "-", 2)
+					fmt.Fprintf(io.Out, "%s %s\n", parts[0], parts[1])
+				}
+				return nil
+			},
+		},
+		&cobra.Command{
+			Use:   "install <repo>",
+			Short: "Install a gh extension from a repository",
+			Args:  cmdutil.MinimumArgs(1, "must specify a repository to install from"),
+			RunE: func(cmd *cobra.Command, args []string) error {
+				if args[0] == "." {
+					wd, err := os.Getwd()
+					if err != nil {
+						return err
+					}
+					return m.InstallLocal(wd)
+				}
+				repo, err := ghrepo.FromFullName(args[0])
+				if err != nil {
+					return err
+				}
+				if !strings.HasPrefix(repo.RepoName(), "gh-") {
+					return errors.New("the repository name must start with `gh-`")
+				}
+				protocol := "https" // TODO: respect user's preferred protocol
+				return m.Install(ghrepo.FormatRemoteURL(repo, protocol), io.Out, io.ErrOut)
+			},
+		},
+		&cobra.Command{
+			Use:   "upgrade",
+			Short: "Upgrade installed extensions",
+			Args:  cobra.NoArgs,
+			RunE: func(cmd *cobra.Command, args []string) error {
+				return m.Upgrade(io.Out, io.ErrOut)
+			},
+		},
+	)
+
+	extCmd.Hidden = true
+	return &extCmd
+}

pkg/cmd/extensions/manager.go

@@ -0,0 +1,121 @@
+package extensions
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/cli/cli/internal/config"
+	"github.com/cli/safeexec"
+)
+
+type Manager struct {
+	dataDir  func() string
+	lookPath func(string) (string, error)
+}
+
+func NewManager() *Manager {
+	return &Manager{
+		dataDir:  config.ConfigDir,
+		lookPath: safeexec.LookPath,
+	}
+}
+
+func (m *Manager) Dispatch(args []string, stdin io.Reader, stdout, stderr io.Writer) (bool, error) {
+	if len(args) == 0 {
+		return false, errors.New("too few arguments in list")
+	}
+
+	var exe string
+	extName := "gh-" + args[0]
+	forwardArgs := args[1:]
+
+	for _, e := range m.List() {
+		if filepath.Base(e) == extName {
+			exe = e
+			break
+		}
+	}
+	if exe == "" {
+		return false, nil
+	}
+
+	// TODO: parse the shebang on Windows and invoke the correct interpreter instead of invoking directly
+	externalCmd := exec.Command(exe, forwardArgs...)
+	externalCmd.Stdin = stdin
+	externalCmd.Stdout = stdout
+	externalCmd.Stderr = stderr
+	return true, externalCmd.Run()
+}
+
+func (m *Manager) List() []string {
+	dir := m.installDir()
+	entries, err := ioutil.ReadDir(dir)
+	if err != nil {
+		return nil
+	}
+
+	var results []string
+	for _, f := range entries {
+		if !strings.HasPrefix(f.Name(), "gh-") || !(f.IsDir() || f.Mode()&os.ModeSymlink != 0) {
+			continue
+		}
+		results = append(results, filepath.Join(dir, f.Name(), f.Name()))
+	}
+	return results
+}
+
+func (m *Manager) InstallLocal(dir string) error {
+	name := filepath.Base(dir)
+	targetDir := filepath.Join(m.installDir(), name)
+	return os.Symlink(dir, targetDir)
+}
+
+func (m *Manager) Install(cloneURL string, stdout, stderr io.Writer) error {
+	exe, err := m.lookPath("git")
+	if err != nil {
+		return err
+	}
+
+	name := strings.TrimSuffix(path.Base(cloneURL), ".git")
+	targetDir := filepath.Join(m.installDir(), name)
+
+	externalCmd := exec.Command(exe, "clone", cloneURL, targetDir)
+	externalCmd.Stdout = stdout
+	externalCmd.Stderr = stderr
+	return externalCmd.Run()
+}
+
+func (m *Manager) Upgrade(stdout, stderr io.Writer) error {
+	exe, err := m.lookPath("git")
+	if err != nil {
+		return err
+	}
+
+	exts := m.List()
+	if len(exts) == 0 {
+		return errors.New("no extensions installed")
+	}
+
+	for _, f := range exts {
+		fmt.Fprintf(stdout, "[%s]: ", filepath.Base(f))
+		dir := filepath.Dir(f)
+		externalCmd := exec.Command(exe, "-C", dir, "--git-dir="+filepath.Join(dir, ".git"), "pull", "--ff-only")
+		externalCmd.Stdout = stdout
+		externalCmd.Stderr = stderr
+		if e := externalCmd.Run(); e != nil {
+			err = e
+		}
+	}
+	return err
+}
+
+func (m *Manager) installDir() string {
+	return filepath.Join(m.dataDir(), "extensions")
+}

pkg/cmd/root/root.go

@@ -13,6 +13,7 @@ import (
 	authCmd "github.com/cli/cli/pkg/cmd/auth"
 	completionCmd "github.com/cli/cli/pkg/cmd/completion"
 	configCmd "github.com/cli/cli/pkg/cmd/config"
+	extensionsCmd "github.com/cli/cli/pkg/cmd/extensions"
 	"github.com/cli/cli/pkg/cmd/factory"
 	gistCmd "github.com/cli/cli/pkg/cmd/gist"
 	issueCmd "github.com/cli/cli/pkg/cmd/issue"
@@ -80,6 +81,7 @@ func NewCmdRoot(f *cmdutil.Factory, version, buildDate string) *cobra.Command {
 	cmd.AddCommand(creditsCmd.NewCmdCredits(f, nil))
 	cmd.AddCommand(gistCmd.NewCmdGist(f))
 	cmd.AddCommand(completionCmd.NewCmdCompletion(f.IOStreams))
+	cmd.AddCommand(extensionsCmd.NewCmdExtensions(f.IOStreams))
 	cmd.AddCommand(secretCmd.NewCmdSecret(f))
 	cmd.AddCommand(sshKeyCmd.NewCmdSSHKey(f))