amazon s3 - Create Image magick object from response stream in go lang -

i using following code download , upload images amazon s3. now, after downloading image want resize using imagick library, without writing on disk. so, how create image magick object directly response stream s3 , upload same on amazon s3. please suggest changes same in below code? also, how change http handler takes value of key query string?

i have commented out code of image magick object reason being sure how write it.

func main() {     file, err := os.create("download_file")          if err != nil {             log.fatal("failed create file", err)         }         defer file.close()          downloader := s3manager.newdownloader(session.new(&aws.config{region: aws.string(region_name)}))         numbytes, err := downloader.download(file,             &s3.getobjectinput{             bucket: aws.string(bucket_name),             key:    aws.string(key),             })         if err != nil {             fmt.println("failed download file", err)             return         }          fmt.println("downloaded file", file.name(), numbytes, "bytes")                          //mw := imagick.newmagickwand()      //   defer mw.destroy()       //  err = mw.readimage(file)      //  if err != nil {      //      panic(err)      //   }           // using io.pipe read/writer file contents.         reader, writer := io.pipe()          go func() {         io.copy(writer, file)          file.close()         writer.close()         }()         uploader := s3manager.newuploader(session.new(&aws.config{region: aws.string(region_name)}))         result, err := uploader.upload(&s3manager.uploadinput{         body:   reader,         bucket: aws.string(bucket),         key:    aws.string(key),         })          if err != nil {         log.fatalln("failed upload", err)         }          log.println("successfully uploaded to", result.location)             fmt.println("code ran successfully")  } 

you need downloadmanager if want download large files more efficiently. downloadmanager requires writerat (generally os.file), have implement on []byte or use file in memory.

if fetch object directly, can read []byte can passed readimageblob:

out, err := s3client.getobject(&s3.getobjectinput{     bucket: aws.string(bucket),     key:    aws.string(key), }) if err != nil {     log.fatal(err) }  img, err := ioutil.readall(out.body) if err != nil {     log.fatal(err) }  mw := imagick.newmagickwand() defer mw.destroy()  err = mw.readimageblob(img) if err != nil {     log.fatal(err) } ...