registry/docs/handlers/helpers.go
Aaron Lehmann 11133181fc Fix CloseNotifier handling and avoid "the ResponseWriter does not implement CloseNotifier" warnings in logs
A change in #763 to address review comments caused problems. Originally,
instrumentedResponseWriter implemented the CloseNotifier interface, and
would panic if it was wrapping something that did not implement that
interface. This was split into a separate instrumentedResponseWriterCN
type that implements CloseNotifier, so there's a fallback if
instrumentedResponseWriter ever needs to wrap something that does not
implement this interface.

instrumentedResponseWriter's Value method would end up upcasting either
type back to instrumentedResponseWriter, which does not implement the
interface. In effect, instrumentedResponseWriterCN was never visible to
the handler.

This fixes the problem by implementing a wrapper Value method for
instrumentedResponseWriterCN.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2015-08-18 17:28:51 -07:00

62 lines
2.1 KiB
Go

package handlers
import (
"errors"
"io"
"net/http"
ctxu "github.com/docker/distribution/context"
"github.com/docker/distribution/registry/api/errcode"
)
// closeResources closes all the provided resources after running the target
// handler.
func closeResources(handler http.Handler, closers ...io.Closer) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
for _, closer := range closers {
defer closer.Close()
}
handler.ServeHTTP(w, r)
})
}
// copyFullPayload copies the payload of a HTTP request to destWriter. If it
// receives less content than expected, and the client disconnected during the
// upload, it avoids sending a 400 error to keep the logs cleaner.
func copyFullPayload(responseWriter http.ResponseWriter, r *http.Request, destWriter io.Writer, context ctxu.Context, action string, errSlice *errcode.Errors) error {
// Get a channel that tells us if the client disconnects
var clientClosed <-chan bool
if notifier, ok := responseWriter.(http.CloseNotifier); ok {
clientClosed = notifier.CloseNotify()
} else {
ctxu.GetLogger(context).Warnf("the ResponseWriter does not implement CloseNotifier (type: %T)", responseWriter)
}
// Read in the data, if any.
copied, err := io.Copy(destWriter, 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:
// Set the response code to "499 Client Closed Request"
// Even though the connection has already been closed,
// this causes the logger to pick up a 499 error
// instead of showing 0 for the HTTP status.
responseWriter.WriteHeader(499)
ctxu.GetLogger(context).Error("client disconnected during " + action)
return errors.New("client disconnected")
default:
}
}
if err != nil {
ctxu.GetLogger(context).Errorf("unknown error reading request payload: %v", err)
*errSlice = append(*errSlice, errcode.ErrorCodeUnknown.WithDetail(err))
return err
}
return nil
}