fix: Do not set backendRequestTimeout when Retries are set (envoyproxy#6421)

* fix: Do not set backendRequestTimeout when Retries are set

Signed-off-by: sudipto baral <sudiptobaral.me@gmail.com>

* fix: update comment

Signed-off-by: sudipto baral <sudiptobaral.me@gmail.com>

---------

Signed-off-by: sudipto baral <sudiptobaral.me@gmail.com>

Author: sudiptob2

internal/gatewayapi/route.go

@@ -325,9 +325,10 @@ func processRouteTimeout(irRoute *ir.HTTPRoute, rule gwapiv1.HTTPRouteRule) {
 			irRoute.Timeout = ptr.To(metav1.Duration{Duration: d})
 		}
 
-		// Also set the IR Route Timeout to the backend request timeout
-		// until we introduce retries, then set it to per try timeout
-		if rule.Timeouts.BackendRequest != nil {
+		// Only set the IR Route Timeout to the backend request timeout
+		// when retries are not configured. When retries are configured,
+		// the backend request timeout should set for per-retry timeout.
+		if rule.Timeouts.BackendRequest != nil && rule.Retry == nil {
 			d, err := time.ParseDuration(string(*rule.Timeouts.BackendRequest))
 			if err != nil {
 				d, _ = time.ParseDuration(HTTPRequestTimeout)

internal/gatewayapi/testdata/httproute-retry.out.yaml

@@ -323,7 +323,6 @@ xdsIR:
           retryOn:
             httpStatusCodes:
             - 500
-        timeout: 3s
         traffic:
           retry:
             numAttemptsPerPriority: 1