func run()

in benchmarks/write_to_gcs/main.go [40:128]
62 lines of code
7 McCabe index (conditional complexity)

func run() (err error) {
	if *fDir == "" {
		err = errors.New("you must set --dir")
		return
	}

	// Create a temporary file.
	log.Printf("Creating a temporary file in %s.", *fDir)

	f, err := os.CreateTemp(*fDir, "write_to_gcs")
	if err != nil {
		err = fmt.Errorf("TempFile: %w", err)
		return
	}

	path := f.Name()

	// Make sure we clean it up later.
	defer func() {
		log.Printf("Deleting %s.", path)
		os.Remove(path)
	}()

	// Write the configured number of zeroes to the file, measuring the time
	// taken.
	log.Println("Writing...")

	buf := make([]byte, *fWriteSize)

	var bytesWritten int64
	start := time.Now()

	for bytesWritten < *fFileSize {
		// Decide how many bytes to write.
		toWrite := *fFileSize - bytesWritten
		if toWrite > *fWriteSize {
			toWrite = *fWriteSize
		}

		// Write them.
		_, err = f.Write(buf)
		if err != nil {
			err = fmt.Errorf("write: %w", err)
			return
		}

		bytesWritten += toWrite
	}

	writeDuration := time.Since(start)

	// Close the file, measuring the time taken.
	log.Println("Flushing...")

	start = time.Now()
	err = f.Close()
	closeDuration := time.Since(start)

	if err != nil {
		err = fmt.Errorf("close: %w", err)
		return
	}

	// Report.
	{
		seconds := float64(writeDuration) / float64(time.Second)
		bytesPerSec := float64(bytesWritten) / seconds

		fmt.Printf(
			"Wrote %s in %v (%s/s)\n",
			format.Bytes(float64(bytesWritten)),
			writeDuration,
			format.Bytes(bytesPerSec))
	}

	{
		seconds := float64(closeDuration) / float64(time.Second)
		bytesPerSec := float64(bytesWritten) / seconds

		fmt.Printf(
			"Flushed %s in %v (%s/s)\n",
			format.Bytes(float64(bytesWritten)),
			closeDuration,
			format.Bytes(bytesPerSec))
	}

	fmt.Println()
	return
}