fix(gatewayapi): http retry without backoff (#9238)

* fix http retry without backoff

Signed-off-by: zirain <zirain2009@gmail.com>

* release notes

Signed-off-by: zirain <zirain2009@gmail.com>

---------

Signed-off-by: zirain <zirain2009@gmail.com>

Author: zirain

internal/gatewayapi/route.go

@@ -542,18 +542,22 @@ func processRouteRetry(irRoute *ir.HTTPRoute, rule *gwapiv1.HTTPRouteRule) {
 	if retry.Backoff != nil {
 		backoff, err := time.ParseDuration(string(*retry.Backoff))
 		if err == nil {
-			res.PerRetry = &ir.PerRetryPolicy{
-				BackOff: &ir.BackOffPolicy{
-					BaseInterval: ir.MetaV1DurationPtr(backoff),
-				},
+			if res.PerRetry == nil {
+				res.PerRetry = &ir.PerRetryPolicy{}
 			}
-			// xref: https://gateway-api.sigs.k8s.io/geps/gep-1742/#timeout-values
-			if rule.Timeouts != nil && rule.Timeouts.BackendRequest != nil {
-				backendRequestTimeout, err := time.ParseDuration(string(*rule.Timeouts.BackendRequest))
-				if err == nil {
-					res.PerRetry.Timeout = ir.MetaV1DurationPtr(backendRequestTimeout)
-				}
+			res.PerRetry.BackOff = &ir.BackOffPolicy{
+				BaseInterval: ir.MetaV1DurationPtr(backoff),
+			}
+		}
+	}
+	// xref: https://gateway-api.sigs.k8s.io/geps/gep-1742/#timeout-values
+	if rule.Timeouts != nil && rule.Timeouts.BackendRequest != nil {
+		backendRequestTimeout, err := time.ParseDuration(string(*rule.Timeouts.BackendRequest))
+		if err == nil {
+			if res.PerRetry == nil {
+				res.PerRetry = &ir.PerRetryPolicy{}
 			}
+			res.PerRetry.Timeout = ir.MetaV1DurationPtr(backendRequestTimeout)
 		}
 	}
 	if len(retry.Codes) > 0 {

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

@@ -54,6 +54,16 @@ httpRoutes:
       backendRefs:
       - name: service-1
         port: 8080
+    - matches:
+      - path:
+          value: "/v2"
+      retry:
+        attempts: 3
+      timeouts:
+        backendRequest: 3s
+      backendRefs:
+      - name: service-1
+        port: 8080
 backendTrafficPolicies:
 - apiVersion: gateway.envoyproxy.io/v1alpha1
   kind: BackendTrafficPolicy

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

@@ -188,6 +188,16 @@ httpRoutes:
         - 500
       timeouts:
         backendRequest: 3s
+    - backendRefs:
+      - name: service-1
+        port: 8080
+      matches:
+      - path:
+          value: /v2
+      retry:
+        attempts: 3
+      timeouts:
+        backendRequest: 3s
   status:
     parents:
     - conditions:
@@ -330,6 +340,60 @@ xdsIR:
         mergeSlashes: true
       port: 10080
       routes:
+      - destination:
+          metadata:
+            kind: HTTPRoute
+            name: httproute-1
+            namespace: default
+          name: httproute/default/httproute-1/rule/1
+          settings:
+          - addressType: IP
+            endpoints:
+            - host: 7.7.7.7
+              port: 8080
+            metadata:
+              kind: Service
+              name: service-1
+              namespace: default
+              sectionName: "8080"
+            name: httproute/default/httproute-1/rule/1/backend/0
+            protocol: HTTP
+            weight: 1
+        hostname: gateway.envoyproxy.io
+        isHTTP2: false
+        metadata:
+          kind: HTTPRoute
+          name: httproute-1
+          namespace: default
+          policies:
+          - kind: BackendTrafficPolicy
+            name: policy-for-route
+            namespace: default
+        name: httproute/default/httproute-1/rule/1/match/0/gateway_envoyproxy_io
+        pathMatch:
+          distinct: false
+          name: ""
+          prefix: /v2
+        retry:
+          numRetries: 3
+          perRetry:
+            timeout: 3s
+        traffic:
+          retry:
+            numAttemptsPerPriority: 1
+            numRetries: 5
+            perRetry:
+              backOff:
+                baseInterval: 100ms
+                maxInterval: 10s
+              timeout: 250ms
+            retryOn:
+              httpStatusCodes:
+              - 429
+              - 503
+              triggers:
+              - connect-failure
+              - retriable-status-codes
       - destination:
           metadata:
             kind: HTTPRoute

release-notes/current.yaml

@@ -47,6 +47,7 @@ bug fixes: |
   Fixed upstream PROXY protocol clusters to preserve generated HTTP protocol options, including auto protocol detection for Backend TLS.
   Fixed EnvoyGateway config hot-reload to apply defaults before validation, so validators always run against a fully-defaulted struct on both the startup and reload paths.
   Fixed deduplicate CA certificates in ClientTrafficPolicy mTLS.
+  Fixed HTTPRoute per-retry timeout (derived from `rule.timeouts.backendRequest`) not being applied when no retry backoff was configured.
   Fixed shared global rate limit rules with a `cost` field not working as expected.
 
 # Enhancements that improve performance.