feat: add update command for sshy to fetch and install the latest version

Author: bornemisza

cmd/update.go

@@ -0,0 +1,285 @@
+package cmd
+
+import (
+	"archive/tar"
+	"archive/zip"
+	"bufio"
+	"compress/gzip"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"github.com/spf13/cobra"
+)
+
+const (
+	githubRepo   = "omisai-tech/sshy"
+	githubAPIURL = "https://api.github.com/repos/" + githubRepo + "/releases/latest"
+)
+
+type githubRelease struct {
+	TagName string `json:"tag_name"`
+	Name    string `json:"name"`
+}
+
+var updateCmd = &cobra.Command{
+	Use:   "update",
+	Short: "Update sshy to the latest version",
+	Long:  `Check for updates and update sshy to the latest release from GitHub.`,
+	RunE:  runUpdate,
+}
+
+func init() {
+	rootCmd.AddCommand(updateCmd)
+}
+
+func runUpdate(cmd *cobra.Command, args []string) error {
+	currentVersion := version
+	fmt.Printf("Current version: %s\n", currentVersion)
+
+	latestVersion, err := fetchLatestVersion()
+	if err != nil {
+		return fmt.Errorf("failed to check for updates: %w", err)
+	}
+	fmt.Printf("Latest version:  %s\n", latestVersion)
+
+	if isLatestVersion(currentVersion, latestVersion) {
+		fmt.Println("\nYou are already running the latest version.")
+		return nil
+	}
+
+	fmt.Printf("\nA new version is available: %s -> %s\n", currentVersion, latestVersion)
+	fmt.Print("Are you sure you want to update? [y/N]: ")
+
+	reader := bufio.NewReader(os.Stdin)
+	response, err := reader.ReadString('\n')
+	if err != nil {
+		return fmt.Errorf("failed to read response: %w", err)
+	}
+
+	response = strings.TrimSpace(strings.ToLower(response))
+	if response != "y" && response != "yes" {
+		fmt.Println("Update cancelled.")
+		return nil
+	}
+
+	if err := performUpdate(latestVersion); err != nil {
+		return fmt.Errorf("failed to update: %w", err)
+	}
+
+	fmt.Printf("\nSuccessfully updated to %s!\n", latestVersion)
+	return nil
+}
+
+func fetchLatestVersion() (string, error) {
+	resp, err := http.Get(githubAPIURL)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("GitHub API returned status %d", resp.StatusCode)
+	}
+
+	var release githubRelease
+	if err := json.NewDecoder(resp.Body).Decode(&release); err != nil {
+		return "", err
+	}
+
+	return release.TagName, nil
+}
+
+func isLatestVersion(current, latest string) bool {
+	current = strings.TrimPrefix(current, "v")
+	latest = strings.TrimPrefix(latest, "v")
+	return current == latest
+}
+
+func performUpdate(version string) error {
+	execPath, err := os.Executable()
+	if err != nil {
+		return fmt.Errorf("failed to get executable path: %w", err)
+	}
+
+	goos := runtime.GOOS
+	goarch := runtime.GOARCH
+
+	versionNum := strings.TrimPrefix(version, "v")
+	var archiveExt string
+	if goos == "windows" {
+		archiveExt = "zip"
+	} else {
+		archiveExt = "tar.gz"
+	}
+
+	downloadURL := fmt.Sprintf(
+		"https://github.com/%s/releases/download/%s/sshy_%s_%s_%s.%s",
+		githubRepo, version, versionNum, goos, goarch, archiveExt,
+	)
+	fmt.Printf("Downloading from: %s\n", downloadURL)
+
+	resp, err := http.Get(downloadURL)
+	if err != nil {
+		return fmt.Errorf("failed to download: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("download failed with status %d", resp.StatusCode)
+	}
+
+	tmpDir, err := os.MkdirTemp("", "sshy-update-*")
+	if err != nil {
+		return fmt.Errorf("failed to create temp directory: %w", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	archivePath := filepath.Join(tmpDir, "sshy."+archiveExt)
+	archiveFile, err := os.Create(archivePath)
+	if err != nil {
+		return fmt.Errorf("failed to create archive file: %w", err)
+	}
+
+	if _, err := io.Copy(archiveFile, resp.Body); err != nil {
+		archiveFile.Close()
+		return fmt.Errorf("failed to write archive: %w", err)
+	}
+	archiveFile.Close()
+
+	var binaryPath string
+	if goos == "windows" {
+		binaryPath, err = extractFromZip(archivePath, tmpDir)
+	} else {
+		binaryPath, err = extractFromTarGz(archivePath, tmpDir)
+	}
+	if err != nil {
+		return fmt.Errorf("failed to extract binary: %w", err)
+	}
+
+	if err := os.Chmod(binaryPath, 0755); err != nil {
+		return fmt.Errorf("failed to set permissions: %w", err)
+	}
+
+	if err := os.Rename(binaryPath, execPath); err != nil {
+		oldPath := execPath + ".old"
+		if renameErr := os.Rename(execPath, oldPath); renameErr != nil {
+			return fmt.Errorf("failed to backup old binary: %w", renameErr)
+		}
+		if copyErr := copyFile(binaryPath, execPath); copyErr != nil {
+			os.Rename(oldPath, execPath)
+			return fmt.Errorf("failed to install update: %w", copyErr)
+		}
+		os.Remove(oldPath)
+	}
+
+	return nil
+}
+
+func extractFromTarGz(archivePath, destDir string) (string, error) {
+	file, err := os.Open(archivePath)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	gzr, err := gzip.NewReader(file)
+	if err != nil {
+		return "", err
+	}
+	defer gzr.Close()
+
+	tr := tar.NewReader(gzr)
+	var binaryPath string
+
+	for {
+		header, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return "", err
+		}
+
+		if header.Typeflag == tar.TypeReg && (header.Name == "sshy" || filepath.Base(header.Name) == "sshy") {
+			binaryPath = filepath.Join(destDir, "sshy")
+			outFile, err := os.Create(binaryPath)
+			if err != nil {
+				return "", err
+			}
+			if _, err := io.Copy(outFile, tr); err != nil {
+				outFile.Close()
+				return "", err
+			}
+			outFile.Close()
+			break
+		}
+	}
+
+	if binaryPath == "" {
+		return "", fmt.Errorf("sshy binary not found in archive")
+	}
+	return binaryPath, nil
+}
+
+func extractFromZip(archivePath, destDir string) (string, error) {
+	r, err := zip.OpenReader(archivePath)
+	if err != nil {
+		return "", err
+	}
+	defer r.Close()
+
+	var binaryPath string
+	for _, f := range r.File {
+		if f.Name == "sshy.exe" || filepath.Base(f.Name) == "sshy.exe" {
+			binaryPath = filepath.Join(destDir, "sshy.exe")
+			rc, err := f.Open()
+			if err != nil {
+				return "", err
+			}
+			outFile, err := os.Create(binaryPath)
+			if err != nil {
+				rc.Close()
+				return "", err
+			}
+			if _, err := io.Copy(outFile, rc); err != nil {
+				outFile.Close()
+				rc.Close()
+				return "", err
+			}
+			outFile.Close()
+			rc.Close()
+			break
+		}
+	}
+
+	if binaryPath == "" {
+		return "", fmt.Errorf("sshy.exe binary not found in archive")
+	}
+	return binaryPath, nil
+}
+
+func copyFile(src, dst string) error {
+	source, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer source.Close()
+
+	destination, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer destination.Close()
+
+	if _, err := io.Copy(destination, source); err != nil {
+		return err
+	}
+
+	return os.Chmod(dst, 0755)
+}