Get file size with goland

GetFileSize.go

package main

import (
	"fmt"
	"io/ioutil"
	"os"
)

func main() {
	if len(os.Args) <= 1 {
		fmt.Printf("Usage: %s [outputPath] \n", os.Args[0])
		return
	}
	dirUrl := os.Args[1]

	ch := make(chan int64)

	go GetDirSize(dirUrl, ch)

	result := <-ch

	fmt.Printf("The %s length = %s(%d bytes)\n", dirUrl, formatFileSize(result), result)
}

func GetDirSize(fileUrl string, ch chan int64) {
	stat, err := os.Stat(fileUrl)
	if err != nil {
		lstat, err := os.Lstat(fileUrl)

		if err != nil {
			panic(err)
		}

		ch <- lstat.Size()

		return
	}
	if stat.IsDir() { // 是文件夹, 遍历 + 递归
		var result int64

		fileInfos, _ := ioutil.ReadDir(fileUrl)

		var channels []chan int64

		for _, subFileInfo := range fileInfos {
			subFileCh := make(chan int64)
			channels = append(channels, subFileCh)
			subFileDir := fmt.Sprintf("%s/%s", fileUrl, subFileInfo.Name())
			go GetDirSize(subFileDir, subFileCh)
		}

		for i := range fileInfos {
			channel := channels[i]
			size := <-channel
			result += size
		}

		ch <- result
	} else { // 文件, 则直接计算长度, 返回
		ch <- stat.Size()
	}
}

func formatFileSize(fileSize int64) (size string) {
	if fileSize < 1024 {
		//return strconv.FormatInt(fileSize, 10) + "B"
		return fmt.Sprintf("%.2fB", float64(fileSize)/float64(1))
	} else if fileSize < (1024 * 1024) {
		return fmt.Sprintf("%.2fKB", float64(fileSize)/float64(1024))
	} else if fileSize < (1024 * 1024 * 1024) {
		return fmt.Sprintf("%.2fMB", float64(fileSize)/float64(1024*1024))
	} else if fileSize < (1024 * 1024 * 1024 * 1024) {
		return fmt.Sprintf("%.2fGB", float64(fileSize)/float64(1024*1024*1024))
	} else if fileSize < (1024 * 1024 * 1024 * 1024 * 1024) {
		return fmt.Sprintf("%.2fTB", float64(fileSize)/float64(1024*1024*1024*1024))
	} else { //if fileSize < (1024 * 1024 * 1024 * 1024 * 1024 * 1024)
		return fmt.Sprintf("%.2fEB", float64(fileSize)/float64(1024*1024*1024*1024*1024))
	}
}