使用Golang的AWS S3并行下载

Question

I am writing a function to download a large file (9GB) from AWS S3 bucket using aws-sdk for go. I need to optimize this and download the file quickly.

func DownloadFromS3Bucket(bucket, item, path string) {
    os.Setenv("AWS_ACCESS_KEY_ID", constants.AWS_ACCESS_KEY_ID)
    os.Setenv("AWS_SECRET_ACCESS_KEY", constants.AWS_SECRET_ACCESS_KEY)

    file, err := os.Create(filepath.Join(path, item))
    if err != nil {
        fmt.Printf("Error in downloading from file: %v 
", err)
        os.Exit(1)
    }

    defer file.Close()

    sess, _ := session.NewSession(&aws.Config{
        Region: aws.String(constants.AWS_REGION)},
    )

    downloader := s3manager.NewDownloader(sess)

    numBytes, err := downloader.Download(file,
        &s3.GetObjectInput{
            Bucket: aws.String(bucket),
            Key:    aws.String(item),
        })
    if err != nil {
        fmt.Printf("Error in downloading from file: %v 
", err)
        os.Exit(1)
    }

    fmt.Println("Download completed", file.Name(), numBytes, "bytes")
}

Can someone suggest a solution to extend this function.

Answer 1

Try altering your NewDownLoader() to this. See https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/#NewDownloader

// Create a downloader with the session and custom options
downloader := s3manager.NewDownloader(sess, func(d *s3manager.Downloader) {
     d.PartSize = 64 * 1024 * 1024 // 64MB per part
     d.Concurrency = 4
})

List of Options that can be set with d. in the func can be found here https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/#Downloader