Random REFUSED_STREAM making a POST multipart form request

This is the code to upload an apk file (several MB) to appetize.io using golang:

func uploadToAppetize(file multipart.File, branchName string, displayName string) (result *AppetizeRes, ok bool) {
file.Seek(0, 0)
url, _ := getUrl()
var buffer bytes.Buffer
writer := multipart.NewWriter(&buffer)
fileName := displayName + "/" + branchName
part, err := writer.CreateFormFile("file", fileName)
if err != nil {
fmt.Fprintf(os.Stderr, "Error creating form file %v: %v\n", fileName, err)
return nil, false
}
size, err := io.Copy(part, file)
if err != nil {
fmt.Fprintf(os.Stderr, "Error copying apk file data: %v\n", err)
return nil, false
}
fmt.Fprintf(os.Stdout, "Copied %v bytes for uploading to appetize...\n", size)
writer.Close()
response, err := http.Post(url, writer.FormDataContentType(), &buffer) // Random error on this line
if err != nil || response == nil {
fmt.Fprintf(os.Stderr, "Error occurred uploading apk data to appetize.io: %v %v\n", err, response)
return nil, false
}
defer response.Body.Close()
if response.StatusCode != http.StatusOK {
return nil, false
}
var appetizeRes AppetizeRes
if err := json.NewDecoder(response.Body).Decode(&appetizeRes); err != nil {
return nil, false
}
return &appetizeRes, true
}

However I am receiving an random error on the line http.Post(...). It returns a nil response and an error. The error is "stream error: stream ID 1; REFUSED_STREAM". It happens randomly but will surely happen the first time the go program make the request after launching.

This is the go version:

go version go1.8.1 darwin/amd64

This is the response header from the server if it doesn't fail:

I also run this program on another mac running go 1.6.*, I didn't remember I ever run into this issue on that mac.

Any idea what's going on?

There is a bug in the golang standard library net/http that fails to handle the REFUSED_STREAM http/2 error properly. This is what is likely going on:

1. golang client opens a TCP connection to the HTTP/2 www server, sets the maximum number of HTTP streams in the connection to 1000 and starts uploading immediately.

2. The HTTP/2 www server tells the golang client to only use a given number of streams, but the golang client has already started more than that amount of streams.

3. The HTTP/2 www server reacts to this by resetting the excess streams.

4. The lack of proper support for a retry in the golang net/http code causes the stream to fail after being reset by the server, and eventually the upload fails as well.

There is a ticket open about this issue on github: x/net/http2: retry requests rejected with REFUSED_STREAM - golang/go/issues/20985

**This issue has been closed in the master branch, the fix will be included in future Golang version 1.10

1: https://github.com/golang/go/issues/20985/ "x/net/http2: retry requests rejected with REFUSED_STREAM"