func ResetLogFiles()

in internal/log/log.go [79:132]
45 lines of code
9 McCabe index (conditional complexity)

func ResetLogFiles(paths []string, fileSizeMaxMB int, fileSizeKeepKB int, logger *Logger) {

	var fileSize int

	for _, path := range paths {
		switch path {
		case "stdout":
			fallthrough
		case "stderr":
			continue
		}
		file, err := os.Open(path)
		if err != nil {
			logger.Error("failed to open existing log file",
				zap.String("file", path),
				zap.Error(err))
			continue
		}

		// Get the file size
		stat, err := file.Stat()
		if err != nil {
			logger.Error("failed to read the FileInfo structure of the log file",
				zap.String("file", path),
				zap.Error(err))
			goto close
		}

		fileSize = int(stat.Size())
		if fileSize > fileSizeMaxMB*1024*1024 {
			logger.Debug("Size of log file is larger than maximum allowed. Resetting.",
				zap.String("file", path),
				zap.Int("current_size_MB", fileSize),
				zap.Int("maximum_allowed_size_MB", fileSizeMaxMB))

			buf := make([]byte, fileSizeKeepKB*1024)
			start := stat.Size() - int64(fileSizeKeepKB*1024)
			if _, err = file.ReadAt(buf, start); err != nil {
				logger.Error("failed to read existing log file",
					zap.String("file", path),
					zap.Error(err))
			} else if err = ioutil.WriteFile(path, buf, 0644); err != nil {
				logger.Error("failed to reset log file",
					zap.String("file", path),
					zap.Error(err))
			}
		}

		// Avoid possible leaks because of using `defer`
	close:
		file.Close()

	}
}