Add --temp-dir flag to allow users to choose where to download and extract images

Author: MatteoPologruto

flash.go

@@ -31,6 +31,7 @@ import (
 
 func newFlashCmd() *cobra.Command {
 	var forceYes bool
+	var tempDir string
 	appCmd := &cobra.Command{
 		Use:   "flash",
 		Short: "Flash a Debian image on the board",
@@ -61,15 +62,17 @@ NOTE: On Windows, required drivers are automatically installed with elevated pri
 			" " + os.Args[0] + " flash ./my-image.tar.zst\n" +
 			" " + os.Args[0] + " flash /path/to/debian-image.tar.zst\n" +
 			" " + os.Args[0] + " flash /path/to/debian-image.tar.xz \n" +
-			" " + os.Args[0] + " flash /path/to/arduino-unoq-debian-image-20250915-173 \n",
+			" " + os.Args[0] + " flash /path/to/arduino-unoq-debian-image-20250915-173 \n" +
+			" " + os.Args[0] + " flash latest --temp-dir /path/to/custom/tempDir \n",
 
 		Args: cobra.ExactArgs(1),
 		Run: func(cmd *cobra.Command, args []string) {
 			checkDriversInstalled()
-			runFlashCommand(cmd.Context(), args, forceYes)
+			runFlashCommand(cmd.Context(), args, forceYes, tempDir)
 		},
 	}
 	appCmd.Flags().BoolVarP(&forceYes, "yes", "y", false, "Automatically confirm all prompts")
+	appCmd.Flags().StringVar(&tempDir, "temp-dir", "", "Path to the directory in which the image will be downloaded and extracted")
 	// TODO: add --clean-install flag or something similar to distinguish between keeping and purging the /home directory
 
 	return appCmd
@@ -86,13 +89,13 @@ func checkDriversInstalled() {
 	}
 }
 
-func runFlashCommand(ctx context.Context, args []string, forceYes bool) {
+func runFlashCommand(ctx context.Context, args []string, forceYes bool, tempDir string) {
 	imagePath, err := paths.New(args[0]).Abs()
 	if err != nil {
 		feedback.Fatal(i18n.Tr("could not find image absolute path: %v", err), feedback.ErrBadArgument)
 	}
 
-	err = updater.Flash(ctx, imagePath, args[0], forceYes)
+	err = updater.Flash(ctx, imagePath, args[0], forceYes, tempDir)
 	if err != nil {
 		feedback.Fatal(i18n.Tr("error flashing the board: %v", err), feedback.ErrBadArgument)
 	}

updater/download_image.go

@@ -46,8 +46,8 @@ type Release struct {
 // DownloadConfirmCB is a function that is called when a Debian image is ready to be downloaded.
 type DownloadConfirmCB func(target string) (bool, error)
 
-func DownloadAndExtract(client *Client, targetVersion string, upgradeConfirmCb DownloadConfirmCB, forceYes bool) (*paths.Path, string, error) {
-	tmpZip, version, err := DownloadImage(client, targetVersion, upgradeConfirmCb, forceYes)
+func DownloadAndExtract(client *Client, targetVersion string, upgradeConfirmCb DownloadConfirmCB, forceYes bool, tempDir string) (*paths.Path, string, error) {
+	tmpZip, version, err := DownloadImage(client, targetVersion, upgradeConfirmCb, forceYes, tempDir)
 	if err != nil {
 		return nil, "", fmt.Errorf("error downloading the image: %v", err)
 	}
@@ -69,7 +69,7 @@ func DownloadAndExtract(client *Client, targetVersion string, upgradeConfirmCb D
 	return imagePath, version, nil
 }
 
-func DownloadImage(client *Client, targetVersion string, upgradeConfirmCb DownloadConfirmCB, forceYes bool) (*paths.Path, string, error) {
+func DownloadImage(client *Client, targetVersion string, upgradeConfirmCb DownloadConfirmCB, forceYes bool, tempDir string) (*paths.Path, string, error) {
 	var err error
 
 	feedback.Print(i18n.Tr("Checking for Debian image releases"))
@@ -112,7 +112,7 @@ func DownloadImage(client *Client, targetVersion string, upgradeConfirmCb Downlo
 	defer download.Close()
 
 	// Download the zip
-	temp, err := GetTempDir("download-")
+	temp, err := GetTempDir("download-", tempDir)
 	if err != nil {
 		return nil, "", fmt.Errorf("could not create temporary download directory: %w", err)
 	}
@@ -166,14 +166,18 @@ func ExtractImage(archive, temp *paths.Path) error {
 
 // GetTempDir returns a temporary directory inside the user's cache directory.
 // The caller is responsible for removing the directory when no longer needed.
-func GetTempDir(prefix string) (*paths.Path, error) {
-	userCacheDir, err := os.UserCacheDir()
-	if err != nil {
-		return nil, fmt.Errorf("could not get user's cache directory: %w", err)
-	}
+func GetTempDir(prefix string, tempDir string) (*paths.Path, error) {
+	cacheDir := paths.New(tempDir)
+
+	if cacheDir == nil {
+		userCacheDir, err := os.UserCacheDir()
+		if err != nil {
+			return nil, fmt.Errorf("could not get user's cache directory: %w", err)
+		}
 
-	cacheDir := paths.New(userCacheDir, "arduino-flasher-cli")
-	_ = cacheDir.MkdirAll()
+		cacheDir = paths.New(userCacheDir, "arduino-flasher-cli")
+		_ = cacheDir.MkdirAll()
+	}
 
 	temp, err := paths.MkTempDir(cacheDir.String(), prefix)
 	if err != nil {

updater/flasher.go

@@ -28,7 +28,7 @@ import (
 	"github.com/arduino/arduino-flasher-cli/updater/artifacts"
 )
 
-func Flash(ctx context.Context, imagePath *paths.Path, version string, forceYes bool) error {
+func Flash(ctx context.Context, imagePath *paths.Path, version string, forceYes bool, tempDir string) error {
 	if !imagePath.Exist() {
 		client := NewClient()
 
@@ -43,7 +43,7 @@ func Flash(ctx context.Context, imagePath *paths.Path, version string, forceYes
 			}
 			yes := strings.ToLower(yesInput) == "yes" || strings.ToLower(yesInput) == "y"
 			return yes, nil
-		}, forceYes)
+		}, forceYes, tempDir)
 
 		if err != nil {
 			return fmt.Errorf("could not download and extract the image: %v", err)
@@ -59,7 +59,7 @@ func Flash(ctx context.Context, imagePath *paths.Path, version string, forceYes
 		version = v
 		imagePath = tempImagePath
 	} else if !imagePath.IsDir() {
-		temp, err := GetTempDir("extract-")
+		temp, err := GetTempDir("extract-", tempDir)
 		if err != nil {
 			return fmt.Errorf("error creating a temporary directory to extract the archive: %v", err)
 		}