golang s3 download with progressbar

golang s3 download with progressbar.go

package awss3

import (
	"crypto/tls"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"time"

  "github.com/schollz/progressbar/v3"
	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3"
	"github.com/aws/aws-sdk-go/service/s3/s3manager"
)

type S3Bucket struct {
	BucketName string
	PathPrefix string
	Region     string
}
func (s *S3Bucket) Download(s3filename string, destPath string) (err error) {
	sess, err := session.NewSession(&aws.Config{
		Region: aws.String(s.Region),
	})
	if utils.CheckFileExist(destPath) {
		_ = os.Remove(destPath)
	}
	destFile, err := os.Create(destPath)
	if err != nil {
		fmt.Println(err)
	}
	defer destFile.Close()

	s3object, err := s.GetObject(s.PathPrefix + "/" + s3filename)
	bar := progressbar.DefaultBytes(
		*s3object.ContentLength,
		"[info] downloading s3: "+s3filename,
	)
	progressbarTicker := time.NewTicker(200 * time.Millisecond)
	quitProgressBarChannel := make(chan interface{})
	go func() {
		for {
			select {
			case <-progressbarTicker.C:
				localObject, err2 := os.Stat(destPath)
				if err2 != nil {
					return
				}
				_ = bar.Set64(localObject.Size())
			case <-quitProgressBarChannel:
				progressbarTicker.Stop()
				return
			}
		}
	}()

	downloader := s3manager.NewDownloader(sess, func(d *s3manager.Downloader) {
		d.PartSize = 64 * 1024 * 1024
		d.Concurrency = 6
	})

	_, err = downloader.Download(destFile,
		&s3.GetObjectInput{
			Bucket: aws.String(s.BucketName),
			Key:    aws.String(s.PathPrefix + "/" + s3filename),
		})

	defer func() {
		time.Sleep(200 * time.Millisecond)
		quitProgressBarChannel <- true
	}()

	if err != nil {
		fmt.Println(err)
	}

	return
}

func (s *S3Bucket) GetObject(objectKey string) (result *s3.GetObjectOutput, err error) {
	client := &http.Client{Transport: &http.Transport{
		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
	}}
	sess, err := session.NewSession(&aws.Config{
		Region: aws.String(s.Region),
	})
	svc := s3.New(sess, &aws.Config{
		HTTPClient: client,
	})
	result, err = svc.GetObject(&s3.GetObjectInput{
		Bucket: aws.String(s.BucketName),
		Key:    aws.String(objectKey),
	})

	return
}