Return error from funcs so that defers are run

If you do an os.Exit from your functions any defer's that are
supposed to be run will not because the application gets terminated.

Defers only run when the function returns so it is better to return
the errs from your functions instead of aborting with an exit.  This
patch also ensures that the error messages are printed on stderr and not
stdout.  FYI, fmt.Print* writes to stdout while the log pkg writes to
stderr.

1 files changed, 43 insertions, 60 deletions

diff --git a/cli/cli.go b/cli/cli.go
index 64723f5..75ec4e7 100644
--- a/cli/cli.go
+++ b/cli/cli.go
@@ -12,7 +12,7 @@ import (
 	"strings"
 )
 
-func List(d *gdrive.Drive, query, titleFilter string, maxResults int, sharedStatus bool, noHeader bool) {
+func List(d *gdrive.Drive, query, titleFilter string, maxResults int, sharedStatus bool, noHeader bool) error {
 	caller := d.Files.List()
 
 	if maxResults > 0 {
@@ -30,8 +30,7 @@ func List(d *gdrive.Drive, query, titleFilter string, maxResults int, sharedStat
 
 	list, err := caller.Do()
 	if err != nil {
-		fmt.Println(err)
-		os.Exit(1)
+		return err
 	}
 
 	items := make([]map[string]string, 0, 0)
@@ -63,6 +62,7 @@ func List(d *gdrive.Drive, query, titleFilter string, maxResults int, sharedStat
 	}
 
 	util.PrintColumns(items, columnOrder, 3, noHeader)
+	return nil
 }
 
 // Adds the key-value-pair 'Shared: True/False' to the map
@@ -96,13 +96,13 @@ func addSharedStatus(d *gdrive.Drive, items []map[string]string) {
 	}
 }
 
-func Info(d *gdrive.Drive, fileId string) {
+func Info(d *gdrive.Drive, fileId string) error {
 	info, err := d.Files.Get(fileId).Do()
 	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 	printInfo(d, info)
+	return nil
 }
 
 func printInfo(d *gdrive.Drive, f *drive.File) {
@@ -135,7 +135,7 @@ func printInfo(d *gdrive.Drive, f *drive.File) {
 }
 
 // Create folder in drive
-func Folder(d *gdrive.Drive, title string, parentId string, share bool) {
+func Folder(d *gdrive.Drive, title string, parentId string, share bool) error {
 	// File instance
 	f := &drive.File{Title: title, MimeType: "application/vnd.google-apps.folder"}
 	// Set parent (if provided)
@@ -146,8 +146,7 @@ func Folder(d *gdrive.Drive, title string, parentId string, share bool) {
 	// Create folder
 	info, err := d.Files.Insert(f).Do()
 	if err != nil {
-		fmt.Printf("An error occurred creating the folder: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred creating the folder: %v\n", err)
 	}
 	// Share folder if the share flag was provided
 	if share {
@@ -155,10 +154,11 @@ func Folder(d *gdrive.Drive, title string, parentId string, share bool) {
 	}
 	printInfo(d, info)
 	fmt.Printf("Folder '%s' created\n", info.Title)
+	return nil
 }
 
 // Upload file to drive
-func Upload(d *gdrive.Drive, input io.ReadCloser, title string, parentId string, share bool, mimeType string) {
+func Upload(d *gdrive.Drive, input io.ReadCloser, title string, parentId string, share bool, mimeType string) error {
 	// Use filename or 'untitled' as title if no title is specified
 	if title == "" {
 		if f, ok := input.(*os.File); ok && input != os.Stdin {
@@ -183,8 +183,7 @@ func Upload(d *gdrive.Drive, input io.ReadCloser, title string, parentId string,
 
 	info, err := d.Files.Insert(f).Media(input).Do()
 	if err != nil {
-		fmt.Printf("An error occurred uploading the document: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred uploading the document: %v\n", err)
 	}
 
 	// Total bytes transferred
@@ -197,40 +196,36 @@ func Upload(d *gdrive.Drive, input io.ReadCloser, title string, parentId string,
 
 	// Share file if the share flag was provided
 	if share {
-		Share(d, info.Id)
+		err = Share(d, info.Id)
 	}
+	return err
 }
 
-func DownloadLatest(d *gdrive.Drive, stdout bool) {
+func DownloadLatest(d *gdrive.Drive, stdout bool) error {
 	list, err := d.Files.List().Do()
-
 	if err != nil {
-		fmt.Println(err)
-		os.Exit(1)
+		return err
 	}
 
 	if len(list.Items) == 0 {
-		fmt.Println("No files found")
-		os.Exit(1)
+		return fmt.Errorf("No files found")
 	}
 
 	latestId := list.Items[0].Id
-	Download(d, latestId, stdout, true)
+	return Download(d, latestId, stdout, true)
 }
 
 // Download file from drive
-func Download(d *gdrive.Drive, fileId string, stdout, deleteAfterDownload bool) {
+func Download(d *gdrive.Drive, fileId string, stdout, deleteAfterDownload bool) error {
 	// Get file info
 	info, err := d.Files.Get(fileId).Do()
 	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 
 	if info.DownloadUrl == "" {
 		// If there is no DownloadUrl, there is no body
-		fmt.Println("An error occurred: File is not downloadable")
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: File is not downloadable")
 	}
 
 	// Measure transfer rate
@@ -239,35 +234,27 @@ func Download(d *gdrive.Drive, fileId string, stdout, deleteAfterDownload bool)
 	// GET the download url
 	res, err := d.Client().Get(info.DownloadUrl)
 	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 
 	// Close body on function exit
 	defer res.Body.Close()
 
-	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
-	}
-
 	// Write file content to stdout
 	if stdout {
 		io.Copy(os.Stdout, res.Body)
-		return
+		return nil
 	}
 
 	// Check if file exists
 	if util.FileExists(info.Title) {
-		fmt.Printf("An error occurred: '%s' already exists\n", info.Title)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: '%s' already exists\n", info.Title)
 	}
 
 	// Create a new file
 	outFile, err := os.Create(info.Title)
 	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 
 	// Close file on function exit
@@ -276,39 +263,38 @@ func Download(d *gdrive.Drive, fileId string, stdout, deleteAfterDownload bool)
 	// Save file to disk
 	bytes, err := io.Copy(outFile, res.Body)
 	if err != nil {
-		fmt.Printf("An error occurred: %v")
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: %s", err)
 	}
 
 	fmt.Printf("Downloaded '%s' at %s, total %s\n", info.Title, getRate(bytes), util.FileSizeFormat(bytes))
 
 	if deleteAfterDownload {
-		Delete(d, fileId)
+		err = Delete(d, fileId)
 	}
+	return err
 }
 
 // Delete file with given file id
-func Delete(d *gdrive.Drive, fileId string) {
+func Delete(d *gdrive.Drive, fileId string) error {
 	info, err := d.Files.Get(fileId).Do()
 	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 
-	if err = d.Files.Delete(fileId).Do(); err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+	if err := d.Files.Delete(fileId).Do(); err != nil {
+		return fmt.Errorf("An error occurred: %v\n", err)
+
 	}
 
 	fmt.Printf("Removed file '%s'\n", info.Title)
+	return nil
 }
 
 // Make given file id readable by anyone -- auth not required to view/download file
-func Share(d *gdrive.Drive, fileId string) {
+func Share(d *gdrive.Drive, fileId string) error {
 	info, err := d.Files.Get(fileId).Do()
 	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 
 	perm := &drive.Permission{
@@ -317,30 +303,27 @@ func Share(d *gdrive.Drive, fileId string) {
 		Role:  "reader",
 	}
 
-	_, err = d.Permissions.Insert(fileId, perm).Do()
-	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+	if _, err := d.Permissions.Insert(fileId, perm).Do(); err != nil {
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 
 	fmt.Printf("File '%s' is now readable by everyone @ %s\n", info.Title, util.PreviewUrl(fileId))
+	return nil
 }
 
 // Removes the 'anyone' permission -- auth will be required to view/download file
-func Unshare(d *gdrive.Drive, fileId string) {
+func Unshare(d *gdrive.Drive, fileId string) error {
 	info, err := d.Files.Get(fileId).Do()
 	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 
-	err = d.Permissions.Delete(fileId, "anyone").Do()
-	if err != nil {
-		fmt.Printf("An error occurred: %v\n", err)
-		os.Exit(1)
+	if err := d.Permissions.Delete(fileId, "anyone").Do(); err != nil {
+		return fmt.Errorf("An error occurred: %v\n", err)
 	}
 
 	fmt.Printf("File '%s' is no longer shared to 'anyone'\n", info.Title)
+	return nil
 }
 
 func isShared(d *gdrive.Drive, fileId string) bool {