Refactor: ensure proper resource cleanup with defer statements in file operations

Author: osmontero

agent/updater/utils/zip.go

@@ -16,27 +16,37 @@ func Unzip(zipFile, destPath string) error {
 	defer archive.Close()
 
 	for _, f := range archive.File {
-		filePath := path.Join(destPath, f.Name)
-		if f.FileInfo().IsDir() {
-			os.MkdirAll(filePath, os.ModePerm)
-			continue
-		}
-		if err := os.MkdirAll(filepath.Dir(filePath), os.ModePerm); err != nil {
-			return err
-		}
-		dstFile, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
-		if err != nil {
-			return err
-		}
-		fileInArchive, err := f.Open()
+		err := func() error {
+			filePath := path.Join(destPath, f.Name)
+			if f.FileInfo().IsDir() {
+				os.MkdirAll(filePath, os.ModePerm)
+				return nil
+			}
+			if err := os.MkdirAll(filepath.Dir(filePath), os.ModePerm); err != nil {
+				return err
+			}
+
+			dstFile, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
+			if err != nil {
+				return err
+			}
+			defer dstFile.Close()
+
+			fileInArchive, err := f.Open()
+			if err != nil {
+				return err
+			}
+			defer fileInArchive.Close()
+
+			if _, err := io.Copy(dstFile, fileInArchive); err != nil {
+				return err
+			}
+
+			return nil
+		}()
 		if err != nil {
 			return err
 		}
-		if _, err := io.Copy(dstFile, fileInArchive); err != nil {
-			return err
-		}
-		dstFile.Close()
-		fileInArchive.Close()
 	}
 	return nil
 }

agent/utils/files.go

@@ -101,6 +101,8 @@ func GenerateFromTemplate(data interface{}, templateFile string, configFile stri
 		return err
 	}
 
+	defer writer.Close()
+
 	err = ut.Execute(writer, data)
 	if err != nil {
 		return err
@@ -132,6 +134,7 @@ func ReadFileLines(path string) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
+
 	defer file.Close()
 
 	var lines []string
@@ -148,6 +151,7 @@ func IsDirEmpty(path string) (bool, error) {
 	if err != nil {
 		return false, err
 	}
+
 	defer f.Close()
 
 	_, err = f.Readdirnames(1)
@@ -163,12 +167,14 @@ func copyFile(src, dst string) error {
 	if err != nil {
 		return err
 	}
+
 	defer sourceFile.Close()
 
 	destFile, err := os.Create(dst)
 	if err != nil {
 		return err
 	}
+
 	defer destFile.Close()
 
 	_, err = io.Copy(destFile, sourceFile)

agent/utils/zip.go

@@ -16,27 +16,37 @@ func Unzip(zipFile, destPath string) error {
 	defer archive.Close()
 
 	for _, f := range archive.File {
-		filePath := path.Join(destPath, f.Name)
-		if f.FileInfo().IsDir() {
-			os.MkdirAll(filePath, os.ModePerm)
-			continue
-		}
-		if err := os.MkdirAll(filepath.Dir(filePath), os.ModePerm); err != nil {
-			return err
-		}
-		dstFile, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
-		if err != nil {
-			return err
-		}
-		fileInArchive, err := f.Open()
+		err := func() error {
+			filePath := path.Join(destPath, f.Name)
+			if f.FileInfo().IsDir() {
+				os.MkdirAll(filePath, os.ModePerm)
+				return nil
+			}
+			if err := os.MkdirAll(filepath.Dir(filePath), os.ModePerm); err != nil {
+				return err
+			}
+
+			dstFile, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
+			if err != nil {
+				return err
+			}
+			defer dstFile.Close()
+
+			fileInArchive, err := f.Open()
+			if err != nil {
+				return err
+			}
+			defer fileInArchive.Close()
+
+			if _, err := io.Copy(dstFile, fileInArchive); err != nil {
+				return err
+			}
+
+			return nil
+		}()
 		if err != nil {
 			return err
 		}
-		if _, err := io.Copy(dstFile, fileInArchive); err != nil {
-			return err
-		}
-		dstFile.Close()
-		fileInArchive.Close()
 	}
 	return nil
 }