untar: call defer file.Close() after each file

deferred calls are only called when the current function ends, which means untar() is currently holding all files open until it has finished processing the whole archive. By introducing `untarFile()` and `unzipFile()` helpers, we can ensure each file is closed as soon as it's fully uncompressed.

Author: guillaumerose

pkg/extract/extract.go

@@ -99,25 +99,30 @@ func untar(reader io.Reader, targetDir string, fileFilter func(string) bool) ([]
 		// if it's a file create it
 		case tar.TypeReg, tar.TypeGNUSparse:
 			// tar.Next() will externally only iterate files, so we might have to create intermediate directories here
-			if err = os.MkdirAll(filepath.Dir(path), 0750); err != nil {
-				return nil, err
-			}
-			file, err := os.OpenFile(path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, header.FileInfo().Mode())
-			if err != nil {
-				return nil, err
-			}
-			defer file.Close()
-
-			// copy over contents
-			// #nosec G110
-			if _, err := io.Copy(file, tarReader); err != nil {
+			if err := untarFile(tarReader, header, path); err != nil {
 				return nil, err
 			}
 			extractedFiles = append(extractedFiles, path)
 		}
 	}
 }
 
+func untarFile(tarReader *tar.Reader, header *tar.Header, path string) error {
+	if err := os.MkdirAll(filepath.Dir(path), 0750); err != nil {
+		return err
+	}
+	file, err := os.OpenFile(path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, header.FileInfo().Mode())
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	// copy over contents
+	// #nosec G110
+	_, err = io.Copy(file, tarReader)
+	return err
+}
+
 func Unzip(archive, target string) ([]string, error) {
 	return unzip(archive, target, nil)
 }
@@ -153,29 +158,34 @@ func unzip(archive, target string, fileFilter func(string) bool) ([]string, erro
 			continue
 		}
 
-		// with a file filter, we may have skipped the intermediate directories, make sure they exist
-		if err = os.MkdirAll(filepath.Dir(path), 0750); err != nil {
+		if err := unzipFile(path, file); err != nil {
 			return nil, err
 		}
+		extractedFiles = append(extractedFiles, path)
+	}
 
-		fileReader, err := file.Open()
-		if err != nil {
-			return nil, err
-		}
-		defer fileReader.Close()
+	return extractedFiles, nil
+}
 
-		targetFile, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, file.Mode())
-		if err != nil {
-			return nil, err
-		}
-		defer targetFile.Close()
+func unzipFile(path string, file *zip.File) error {
+	// with a file filter, we may have skipped the intermediate directories, make sure they exist
+	if err := os.MkdirAll(filepath.Dir(path), 0750); err != nil {
+		return err
+	}
 
-		// #nosec G110
-		if _, err := io.Copy(targetFile, fileReader); err != nil {
-			return nil, err
-		}
-		extractedFiles = append(extractedFiles, path)
+	fileReader, err := file.Open()
+	if err != nil {
+		return err
 	}
+	defer fileReader.Close()
 
-	return extractedFiles, nil
+	targetFile, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, file.Mode())
+	if err != nil {
+		return err
+	}
+	defer targetFile.Close()
+
+	// #nosec G110
+	_, err = io.Copy(targetFile, fileReader)
+	return err
 }