func()

in machine.go [679:723]

• 29 lines of code
• 6 McCabe index (conditional complexity)

func (m *Machine) captureFifoToFileWithChannel(ctx context.Context, logger *log.Entry, fifoPath string, w io.Writer, done chan error) error {
	// open the fifo pipe which will be used
	// to write its contents to a file.
	fifoPipe, err := fifo.OpenFifo(ctx, fifoPath, syscall.O_RDONLY|syscall.O_NONBLOCK, 0600)
	if err != nil {
		return fmt.Errorf("Failed to open fifo path at %q: %v", fifoPath, err)
	}

	logger.Debugf("Capturing %q to writer", fifoPath)

	// this goroutine is to track the life of the application along with whether
	// or not the context has been cancelled which is signified by the exitCh. In
	// the event that the exitCh has been closed, we will close the fifo file.
	go func() {
		<-m.exitCh
		if err := fifoPipe.Close(); err != nil {
			logger.WithError(err).Debug("failed to close fifo")
		}
	}()

	// Uses a goroutine to copy the contents of the fifo pipe to the io.Writer.
	// In the event that the goroutine finishes, which is caused by either the
	// context being closed or the application being closed, we will close the
	// pipe and unlink the fifo path.
	go func() {
		defer func() {
			if err := fifoPipe.Close(); err != nil {
				logger.Warnf("Failed to close fifo pipe: %v", err)
			}

			if err := syscall.Unlink(fifoPath); err != nil {
				logger.Warnf("Failed to unlink %s: %v", fifoPath, err)
			}
		}()

		if _, err := io.Copy(w, fifoPipe); err != nil {
			logger.WithError(err).Warn("io.Copy failed to copy contents of fifo pipe")
			done <- err
		}

		close(done)
	}()

	return nil
}