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Merge branch v2.11 into v3.3

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kevinpollet 2025-02-24 15:57:50 +01:00
commit 32ea014d07
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13 changed files with 351 additions and 215 deletions
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86
pkg/middlewares/retry/retry.go
View file

@ -36,6 +36,48 @@ type Listener interface {
// each of them about a retry attempt.
type Listeners []Listener
// Retried exists to implement the Listener interface. It calls Retried on each of its slice entries.
func (l Listeners) Retried(req *http.Request, attempt int) {
for _, listener := range l {
listener.Retried(req, attempt)
}
}
type shouldRetryContextKey struct{}
// ShouldRetry is a function allowing to enable/disable the retry middleware mechanism.
type ShouldRetry func(shouldRetry bool)
// ContextShouldRetry returns the ShouldRetry function if it has been set by the Retry middleware in the chain.
func ContextShouldRetry(ctx context.Context) ShouldRetry {
f, _ := ctx.Value(shouldRetryContextKey{}).(ShouldRetry)
return f
}
// WrapHandler wraps a given http.Handler to inject the httptrace.ClientTrace in the request context when it is needed
// by the retry middleware.
func WrapHandler(next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
if shouldRetry := ContextShouldRetry(req.Context()); shouldRetry != nil {
shouldRetry(true)
trace := &httptrace.ClientTrace{
WroteHeaders: func() {
shouldRetry(false)
},
WroteRequest: func(httptrace.WroteRequestInfo) {
shouldRetry(false)
},
}
newCtx := httptrace.WithClientTrace(req.Context(), trace)
next.ServeHTTP(rw, req.WithContext(newCtx))
return
}
next.ServeHTTP(rw, req)
})
}
// retry is a middleware that retries requests.
type retry struct {
attempts int
@ -101,19 +143,13 @@ func (r *retry) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
req = req.WithContext(tracingCtx)
}
shouldRetry := attempts < r.attempts
retryResponseWriter := newResponseWriter(rw, shouldRetry)
remainAttempts := attempts < r.attempts
retryResponseWriter := newResponseWriter(rw)
// Disable retries when the backend already received request data
clientTrace := &httptrace.ClientTrace{
WroteHeaders: func() {
retryResponseWriter.DisableRetries()
},
WroteRequest: func(httptrace.WroteRequestInfo) {
retryResponseWriter.DisableRetries()
},
var shouldRetry ShouldRetry = func(shouldRetry bool) {
retryResponseWriter.SetShouldRetry(remainAttempts && shouldRetry)
}
newCtx := httptrace.WithClientTrace(req.Context(), clientTrace)
newCtx := context.WithValue(req.Context(), shouldRetryContextKey{}, shouldRetry)
r.next.ServeHTTP(retryResponseWriter, req.Clone(newCtx))
@ -164,18 +200,10 @@ func (r *retry) newBackOff() backoff.BackOff {
return b
}
// Retried exists to implement the Listener interface. It calls Retried on each of its slice entries.
func (l Listeners) Retried(req *http.Request, attempt int) {
for _, listener := range l {
listener.Retried(req, attempt)
}
}
func newResponseWriter(rw http.ResponseWriter, shouldRetry bool) *responseWriter {
func newResponseWriter(rw http.ResponseWriter) *responseWriter {
return &responseWriter{
responseWriter: rw,
headers: make(http.Header),
shouldRetry: shouldRetry,
}
}
@ -190,8 +218,8 @@ func (r *responseWriter) ShouldRetry() bool {
return r.shouldRetry
}
func (r *responseWriter) DisableRetries() {
r.shouldRetry = false
func (r *responseWriter) SetShouldRetry(shouldRetry bool) {
r.shouldRetry = shouldRetry
}
func (r *responseWriter) Header() http.Header {
@ -205,20 +233,14 @@ func (r *responseWriter) Write(buf []byte) (int, error) {
if r.ShouldRetry() {
return len(buf), nil
}
if !r.written {
r.WriteHeader(http.StatusOK)
}
return r.responseWriter.Write(buf)
}
func (r *responseWriter) WriteHeader(code int) {
if r.ShouldRetry() && code == http.StatusServiceUnavailable {
// We get a 503 HTTP Status Code when there is no backend server in the pool
// to which the request could be sent. Also, note that r.ShouldRetry()
// will never return true in case there was a connection established to
// the backend server and so we can be sure that the 503 was produced
// inside Traefik already and we don't have to retry in this cases.
r.DisableRetries()
}
if r.ShouldRetry() || r.written {
if r.shouldRetry || r.written {
return
}

108
pkg/middlewares/retry/retry_test.go
View file

@ -105,12 +105,21 @@ func TestRetry(t *testing.T) {
t.Parallel()
retryAttempts := 0
next := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
// This signals that a connection will be established with the backend
// to enable the Retry middleware mechanism.
shouldRetry := ContextShouldRetry(req.Context())
if shouldRetry != nil {
shouldRetry(true)
}
retryAttempts++
if retryAttempts > test.amountFaultyEndpoints {
// calls WroteHeaders on httptrace.
_ = r.Write(io.Discard)
// This signals that request headers have been sent to the backend.
if shouldRetry != nil {
shouldRetry(false)
}
rw.WriteHeader(http.StatusOK)
return
@ -152,27 +161,16 @@ func TestRetryEmptyServerList(t *testing.T) {
assert.Equal(t, 0, retryListener.timesCalled)
}
func TestRetryListeners(t *testing.T) {
req := httptest.NewRequest(http.MethodGet, "/", nil)
retryListeners := Listeners{&countingRetryListener{}, &countingRetryListener{}}
retryListeners.Retried(req, 1)
retryListeners.Retried(req, 1)
for _, retryListener := range retryListeners {
listener := retryListener.(*countingRetryListener)
if listener.timesCalled != 2 {
t.Errorf("retry listener was called %d time(s), want %d time(s)", listener.timesCalled, 2)
}
}
}
func TestMultipleRetriesShouldNotLooseHeaders(t *testing.T) {
attempt := 0
expectedHeaderName := "X-Foo-Test-2"
expectedHeaderValue := "bar"
next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
shouldRetry := ContextShouldRetry(req.Context())
if shouldRetry != nil {
shouldRetry(true)
}
headerName := fmt.Sprintf("X-Foo-Test-%d", attempt)
rw.Header().Add(headerName, expectedHeaderValue)
if attempt < 2 {
@ -181,43 +179,54 @@ func TestMultipleRetriesShouldNotLooseHeaders(t *testing.T) {
}
// Request has been successfully written to backend
trace := httptrace.ContextClientTrace(req.Context())
trace.WroteHeaders()
shouldRetry(false)
// And we decide to answer to client
// And we decide to answer to client.
rw.WriteHeader(http.StatusNoContent)
})
retry, err := New(context.Background(), next, dynamic.Retry{Attempts: 3}, &countingRetryListener{}, "traefikTest")
require.NoError(t, err)
responseRecorder := httptest.NewRecorder()
retry.ServeHTTP(responseRecorder, testhelpers.MustNewRequest(http.MethodGet, "http://test", http.NoBody))
res := httptest.NewRecorder()
retry.ServeHTTP(res, testhelpers.MustNewRequest(http.MethodGet, "http://test", http.NoBody))
headerValue := responseRecorder.Header().Get(expectedHeaderName)
// Validate if we have the correct header
if headerValue != expectedHeaderValue {
t.Errorf("Expected to have %s for header %s, got %s", expectedHeaderValue, expectedHeaderName, headerValue)
}
// The third header attempt is kept.
headerValue := res.Header().Get("X-Foo-Test-2")
assert.Equal(t, expectedHeaderValue, headerValue)
// Validate that we don't have headers from previous attempts
for i := range attempt {
headerName := fmt.Sprintf("X-Foo-Test-%d", i)
headerValue = responseRecorder.Header().Get("headerName")
headerValue = res.Header().Get(headerName)
if headerValue != "" {
t.Errorf("Expected no value for header %s, got %s", headerName, headerValue)
}
}
}
// countingRetryListener is a Listener implementation to count the times the Retried fn is called.
type countingRetryListener struct {
timesCalled int
}
func TestRetryShouldNotLooseHeadersOnWrite(t *testing.T) {
next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Add("X-Foo-Test", "bar")
func (l *countingRetryListener) Retried(req *http.Request, attempt int) {
l.timesCalled++
// Request has been successfully written to backend.
shouldRetry := ContextShouldRetry(req.Context())
if shouldRetry != nil {
shouldRetry(false)
}
// And we decide to answer to client without calling WriteHeader.
_, err := rw.Write([]byte("bar"))
require.NoError(t, err)
})
retry, err := New(context.Background(), next, dynamic.Retry{Attempts: 3}, &countingRetryListener{}, "traefikTest")
require.NoError(t, err)
res := httptest.NewRecorder()
retry.ServeHTTP(res, testhelpers.MustNewRequest(http.MethodGet, "http://test", http.NoBody))
headerValue := res.Header().Get("X-Foo-Test")
assert.Equal(t, "bar", headerValue)
}
func TestRetryWithFlush(t *testing.T) {
@ -275,12 +284,24 @@ func TestRetryWebsocket(t *testing.T) {
t.Parallel()
retryAttempts := 0
next := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
// This signals that a connection will be established with the backend
// to enable the Retry middleware mechanism.
shouldRetry := ContextShouldRetry(req.Context())
if shouldRetry != nil {
shouldRetry(true)
}
retryAttempts++
if retryAttempts > test.amountFaultyEndpoints {
// This signals that request headers have been sent to the backend.
if shouldRetry != nil {
shouldRetry(false)
}
upgrader := websocket.Upgrader{}
_, err := upgrader.Upgrade(rw, r, nil)
_, err := upgrader.Upgrade(rw, req, nil)
if err != nil {
http.Error(rw, err.Error(), http.StatusInternalServerError)
}
@ -387,3 +408,12 @@ func Test1xxResponses(t *testing.T) {
assert.Equal(t, 0, retryListener.timesCalled)
}
// countingRetryListener is a Listener implementation to count the times the Retried fn is called.
type countingRetryListener struct {
timesCalled int
}
func (l *countingRetryListener) Retried(req *http.Request, attempt int) {
l.timesCalled++
}