How to convert aws.WriteAtBuffer to an io.Reader?

Question

I need to download a file from S3, and then upload the same file into a different S3 bucket. So far I have:

sess := session.Must(session.NewSession())
downloader := s3manager.NewDownloader(sess)

buffer := aws.NewWriteAtBuffer([]byte{})

n, err := downloader.Download(buffer, &s3.GetObjectInput{
    Bucket: aws.String(sourceS3Bucket),
    Key:    aws.String(documentKey),
})

uploader := s3manager.NewUploader(sess)
result, err := uploader.Upload(&s3manager.UploadInput{
    Bucket: aws.String(targetS3Bucket),
    Key:    aws.String(documentKey),
    Body:   buffer,
})

I have used an aws.WriteAtBuffer, as per the answer here: https://stackoverflow.com/a/48254996/504055

However, I am currently stuck on how to treat this buffer as something that implements the io.Reader interface, which is what the uploader's Upload method requires.

score 6 · Accepted Answer · edited Oct 29 '19 at 03:42

6

Use bytes.NewReader to create an io.Reader on the bytes in the buffer:

result, err := uploader.Upload(&s3manager.UploadInput{
    Bucket: aws.String(targetS3Bucket),
    Key:    aws.String(documentKey),
    Body:   bytes.NewReader(buffer.Bytes()),
})

edited Oct 29 '19 at 03:42

sberry

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answered Oct 29 '19 at 03:33

How to convert aws.WriteAtBuffer to an io.Reader?

1 Answers1