implement request cancellation in token transport

staging/src/k8s.io/client-go/transport/round_trippers.go

@@ -80,10 +80,6 @@ func DebugWrappers(rt http.RoundTripper) http.RoundTripper {
 	return rt
 }
 
-type requestCanceler interface {
-	CancelRequest(*http.Request)
-}
-
 type authProxyRoundTripper struct {
 	username string
 	groups   []string
@@ -140,11 +136,7 @@ func SetAuthProxyHeaders(req *http.Request, username string, groups []string, ex
 }
 
 func (rt *authProxyRoundTripper) CancelRequest(req *http.Request) {
-	if canceler, ok := rt.rt.(requestCanceler); ok {
-		canceler.CancelRequest(req)
-	} else {
-		klog.Errorf("CancelRequest not implemented by %T", rt.rt)
-	}
+	tryCancelRequest(rt.WrappedRoundTripper(), req)
 }
 
 func (rt *authProxyRoundTripper) WrappedRoundTripper() http.RoundTripper { return rt.rt }
@@ -168,11 +160,7 @@ func (rt *userAgentRoundTripper) RoundTrip(req *http.Request) (*http.Response, e
 }
 
 func (rt *userAgentRoundTripper) CancelRequest(req *http.Request) {
-	if canceler, ok := rt.rt.(requestCanceler); ok {
-		canceler.CancelRequest(req)
-	} else {
-		klog.Errorf("CancelRequest not implemented by %T", rt.rt)
-	}
+	tryCancelRequest(rt.WrappedRoundTripper(), req)
 }
 
 func (rt *userAgentRoundTripper) WrappedRoundTripper() http.RoundTripper { return rt.rt }
@@ -199,11 +187,7 @@ func (rt *basicAuthRoundTripper) RoundTrip(req *http.Request) (*http.Response, e
 }
 
 func (rt *basicAuthRoundTripper) CancelRequest(req *http.Request) {
-	if canceler, ok := rt.rt.(requestCanceler); ok {
-		canceler.CancelRequest(req)
-	} else {
-		klog.Errorf("CancelRequest not implemented by %T", rt.rt)
-	}
+	tryCancelRequest(rt.WrappedRoundTripper(), req)
 }
 
 func (rt *basicAuthRoundTripper) WrappedRoundTripper() http.RoundTripper { return rt.rt }
@@ -259,11 +243,7 @@ func (rt *impersonatingRoundTripper) RoundTrip(req *http.Request) (*http.Respons
 }
 
 func (rt *impersonatingRoundTripper) CancelRequest(req *http.Request) {
-	if canceler, ok := rt.delegate.(requestCanceler); ok {
-		canceler.CancelRequest(req)
-	} else {
-		klog.Errorf("CancelRequest not implemented by %T", rt.delegate)
-	}
+	tryCancelRequest(rt.WrappedRoundTripper(), req)
 }
 
 func (rt *impersonatingRoundTripper) WrappedRoundTripper() http.RoundTripper { return rt.delegate }
@@ -318,11 +298,7 @@ func (rt *bearerAuthRoundTripper) RoundTrip(req *http.Request) (*http.Response,
 }
 
 func (rt *bearerAuthRoundTripper) CancelRequest(req *http.Request) {
-	if canceler, ok := rt.rt.(requestCanceler); ok {
-		canceler.CancelRequest(req)
-	} else {
-		klog.Errorf("CancelRequest not implemented by %T", rt.rt)
-	}
+	tryCancelRequest(rt.WrappedRoundTripper(), req)
 }
 
 func (rt *bearerAuthRoundTripper) WrappedRoundTripper() http.RoundTripper { return rt.rt }
@@ -402,11 +378,7 @@ func newDebuggingRoundTripper(rt http.RoundTripper, levels ...debugLevel) *debug
 }
 
 func (rt *debuggingRoundTripper) CancelRequest(req *http.Request) {
-	if canceler, ok := rt.delegatedRoundTripper.(requestCanceler); ok {
-		canceler.CancelRequest(req)
-	} else {
-		klog.Errorf("CancelRequest not implemented by %T", rt.delegatedRoundTripper)
-	}
+	tryCancelRequest(rt.WrappedRoundTripper(), req)
 }
 
 var knownAuthTypes = map[string]bool{

staging/src/k8s.io/client-go/transport/token_source.go

@@ -25,6 +25,7 @@ import (
 	"time"
 
 	"golang.org/x/oauth2"
+
 	"k8s.io/klog"
 )
 
@@ -81,6 +82,14 @@ func (tst *tokenSourceTransport) RoundTrip(req *http.Request) (*http.Response, e
 	return tst.ort.RoundTrip(req)
 }
 
+func (tst *tokenSourceTransport) CancelRequest(req *http.Request) {
+	if req.Header.Get("Authorization") != "" {
+		tryCancelRequest(tst.base, req)
+		return
+	}
+	tryCancelRequest(tst.ort, req)
+}
+
 type fileTokenSource struct {
 	path   string
 	period time.Duration

staging/src/k8s.io/client-go/transport/token_source_test.go

@@ -18,6 +18,7 @@ package transport
 
 import (
 	"fmt"
+	"net/http"
 	"reflect"
 	"sync"
 	"testing"
@@ -154,3 +155,85 @@ func TestCachingTokenSourceRace(t *testing.T) {
 		}
 	}
 }
+
+type uncancellableRT struct {
+	rt http.RoundTripper
+}
+
+func (urt *uncancellableRT) RoundTrip(req *http.Request) (*http.Response, error) {
+	return urt.rt.RoundTrip(req)
+}
+
+func TestCancellation(t *testing.T) {
+	tests := []struct {
+		name          string
+		header        http.Header
+		wrapTransport func(http.RoundTripper) http.RoundTripper
+		expectCancel  bool
+	}{
+		{
+			name:         "cancel req with bearer token skips oauth rt",
+			header:       map[string][]string{"Authorization": {"Bearer TOKEN"}},
+			expectCancel: true,
+		},
+		{
+			name:         "cancel req without bearer token hits both rts",
+			expectCancel: true,
+		},
+		{
+			name: "cancel req without bearer token hits both wrapped rts",
+			wrapTransport: func(rt http.RoundTripper) http.RoundTripper {
+				return NewUserAgentRoundTripper("testing testing", rt)
+			},
+			expectCancel: true,
+		},
+		{
+			name: "can't cancel request with rts that doesn't implent unwrap or cancel",
+			wrapTransport: func(rt http.RoundTripper) http.RoundTripper {
+				return &uncancellableRT{rt: rt}
+			},
+			expectCancel: false,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			baseRecorder := &recordCancelRoundTripper{}
+
+			var base http.RoundTripper = baseRecorder
+			if test.wrapTransport != nil {
+				base = test.wrapTransport(base)
+			}
+
+			rt := &tokenSourceTransport{
+				base: base,
+				ort: &oauth2.Transport{
+					Base: base,
+				},
+			}
+
+			rt.CancelRequest(&http.Request{
+				Header: test.header,
+			})
+
+			if baseRecorder.canceled != test.expectCancel {
+				t.Errorf("unexpected cancel: got=%v, want=%v", baseRecorder.canceled, test.expectCancel)
+			}
+		})
+	}
+}
+
+type recordCancelRoundTripper struct {
+	canceled bool
+	base     http.RoundTripper
+}
+
+func (rt *recordCancelRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	return nil, nil
+}
+
+func (rt *recordCancelRoundTripper) CancelRequest(req *http.Request) {
+	rt.canceled = true
+	if rt.base != nil {
+		tryCancelRequest(rt.base, req)
+	}
+}

staging/src/k8s.io/client-go/transport/transport.go

@@ -23,6 +23,9 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net/http"
+
+	utilnet "k8s.io/apimachinery/pkg/util/net"
+	"k8s.io/klog"
 )
 
 // New returns an http.RoundTripper that will provide the authentication
@@ -225,3 +228,17 @@ func (b *contextCanceller) RoundTrip(req *http.Request) (*http.Response, error)
 		return b.rt.RoundTrip(req)
 	}
 }
+
+func tryCancelRequest(rt http.RoundTripper, req *http.Request) {
+	type canceler interface {
+		CancelRequest(*http.Request)
+	}
+	switch rt := rt.(type) {
+	case canceler:
+		rt.CancelRequest(req)
+	case utilnet.RoundTripperWrapper:
+		tryCancelRequest(rt.WrappedRoundTripper(), req)
+	default:
+		klog.Warningf("Unable to cancel request for %T", rt)
+	}
+}