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Use CloseNotifier to supress spurious HTTP 400 errors on early disconnect

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When a client disconnects without completing a HTTP request, we were
attempting to process the partial request, which usually leads to a 400
error. These errors can pollute the logs and make it more difficult to
track down real bugs.

This change uses CloseNotifier to detect disconnects. In combination
with checking Content-Length, we can detect a disconnect before sending
the full payload, and avoid logging a 400 error.

This logic is only applied to PUT, POST, and PATCH endpoints, as these
are the places where disconnects during a request are most likely to
happen.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This commit is contained in:
Aaron Lehmann 2015-07-27 10:00:00 -07:00
parent 9dac3cc571
commit 8fbc1de081
2 changed files with 70 additions and 4 deletions
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44
docs/handlers/blobupload.go
View file

@ -170,8 +170,28 @@ func (buh *blobUploadHandler) PatchBlobData(w http.ResponseWriter, r *http.Reque
// TODO(dmcgowan): support Content-Range header to seek and write range
// Get a channel that tells us if the client disconnects
var clientClosed <-chan bool
if notifier, ok := w.(http.CloseNotifier); ok {
clientClosed = notifier.CloseNotify()
} else {
panic("the ResponseWriter does not implement CloseNotifier")
}
// Copy the data
if _, err := io.Copy(buh.Upload, r.Body); err != nil {
copied, err := io.Copy(buh.Upload, r.Body)
if clientClosed != nil && (err != nil || (r.ContentLength > 0 && copied < r.ContentLength)) {
// Didn't recieve as much content as expected. Did the client
// disconnect during the request? If so, avoid returning a 400
// error to keep the logs cleaner.
select {
case <-clientClosed:
ctxu.GetLogger(buh).Error("client disconnected during blob PATCH")
return
default:
}
}
if err != nil {
ctxu.GetLogger(buh).Errorf("unknown error copying into upload: %v", err)
buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
return
@ -211,8 +231,28 @@ func (buh *blobUploadHandler) PutBlobUploadComplete(w http.ResponseWriter, r *ht
return
}
// Get a channel that tells us if the client disconnects
var clientClosed <-chan bool
if notifier, ok := w.(http.CloseNotifier); ok {
clientClosed = notifier.CloseNotify()
} else {
panic("the ResponseWriter does not implement CloseNotifier")
}
// Read in the data, if any.
if _, err := io.Copy(buh.Upload, r.Body); err != nil {
copied, err := io.Copy(buh.Upload, r.Body)
if clientClosed != nil && (err != nil || (r.ContentLength > 0 && copied < r.ContentLength)) {
// Didn't recieve as much content as expected. Did the client
// disconnect during the request? If so, avoid returning a 400
// error to keep the logs cleaner.
select {
case <-clientClosed:
ctxu.GetLogger(buh).Error("client disconnected during blob PUT")
return
default:
}
}
if err != nil {
ctxu.GetLogger(buh).Errorf("unknown error copying into upload: %v", err)
buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
return