Thanks for your reply.
After read your message, this are my test.
cmd := exec.Command("mysqldump", args_mysqldump...)
r, w := io.Pipe()
z := zlib.NewWriter(w)
defer z.Close()
cmd.Stdout = z
cmd.Start()
uploader := s3manager.NewUploader(session.New(&aws.Config{Region
: aws.String(t.S3.AwsRegion)}))
// Set default part size at 50MB
uploader.PartSize = 104857600
uploader.Upload(&s3manager.UploadInput{
Body: r,
Bucket: aws.String(t.S3.Backet),
Key: aws.String(path.Join(t.S3.Prefix, file_name)),
})
done := make(chan error)
go func() {
done <- cmd.Wait()
}()
but there is a problem, this stop in s3manager and never finish, but if I
add go rutine in s3manager the program continue and finish without to do
anything.
I dont know where is my mistake.
Well thanks in advance
Regards
El jueves, 13 de octubre de 2016, 15:20:22 (UTC-3), Konstantin Khomoutov
escribió:
>
> On Thu, 13 Oct 2016 10:43:24 -0700 (PDT)
> Walter Garcia <wal...@gmail.com <javascript:>> wrote:
>
> > Im trying to test using zlib.
> >
> > In my test I need compress the Stdout from exec.Command to zlib and
> > then send to io.reader to use in other service
> >
> > cmd := exec.Command("mysqldump", args...)
> > ......
> > cmd.StdoutPipe()
> >
> > z := zlib.NewWriter( ... )
> > .....
> > z -> to -> io.reader
> >
> > Could you help me?
>
> You can't do that directly because you can only write to io.Writer-s.
> This is reasonable if you stop and think about it for a moment: an
> io.Writer is a "push-style" interface -- you write something to
> whatever is implementing it and block until that action happens; --
> conversely, io.Reader is a "pull-style" interface -- you read something
> from a source and that blocks until the source is ready.
>
> To glue a writer and a reader you need some intermediate "thing" which
> would simultaneostly be a reader and a writer (!) -- so that it
> satisfies both kinds of interfaces described above.
>
> Such things are called "pipes" and Go provides at least two of them:
>
> * io.Pipe is a pure-Go pipe;
> * os.Pipe is a pipe provided by the underlying kernel.
>
> The former is supposedly what you need.
>
> Still note that to make
>
> z -> pipe -> io.reader
>
> really work the "z" and the "io.reader" parts have to be in separate
> goroutines otherwise they will block one another.
>
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