From a7cd4c0ad64d785b3fbff90a2a8371841dc8ba0a Mon Sep 17 00:00:00 2001
From: hellocn9 <zhangyancn9@126.com>
Date: Thu, 16 Oct 2025 15:36:05 +0800
Subject: [PATCH] feat(ingress): support custom parameter names for MCP SSE
 stateful sessions (#3008)

---
 pkg/ingress/config/ingress_config.go        | 10 +++++-----
 pkg/ingress/kube/annotations/loadbalance.go | 17 +++++++++++++----
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/pkg/ingress/config/ingress_config.go b/pkg/ingress/config/ingress_config.go
index 7a4363eac..c211246de 100644
--- a/pkg/ingress/config/ingress_config.go
+++ b/pkg/ingress/config/ingress_config.go
@@ -653,7 +653,7 @@ func (m *IngressConfig) convertEnvoyFilter(convertOptions *common.ConvertOptions
 			loadBalance := route.WrapperConfig.AnnotationsConfig.LoadBalance
 			if loadBalance != nil && loadBalance.McpSseStateful {
 				IngressLog.Infof("Found MCP SSE stateful session for route %s", route.HTTPRoute.Name)
-				envoyFilter, err := m.constructMcpSseStatefulSessionEnvoyFilter(route, m.namespace, initMcpSseGlobalFilter)
+				envoyFilter, err := m.constructMcpSseStatefulSessionEnvoyFilter(route, m.namespace, initMcpSseGlobalFilter, loadBalance.McpSseStatefulKey)
 				if err != nil {
 					IngressLog.Errorf("Construct MCP SSE stateful session EnvoyFilter error %v", err)
 				} else {
@@ -1956,7 +1956,7 @@ func (m *IngressConfig) Delete(config.GroupVersionKind, string, string, *string)
 	return common.ErrUnsupportedOp
 }
 
-func (m *IngressConfig) constructMcpSseStatefulSessionEnvoyFilter(route *common.WrapperHTTPRoute, namespace string, initGlobalFilter bool) (*config.Config, error) {
+func (m *IngressConfig) constructMcpSseStatefulSessionEnvoyFilter(route *common.WrapperHTTPRoute, namespace string, initGlobalFilter bool, mcpSseStatefulKey string) (*config.Config, error) {
 	httpRoute := route.HTTPRoute
 
 	var configPatches []*networking.EnvoyFilter_EnvoyConfigObjectPatch
@@ -2010,7 +2010,7 @@ func (m *IngressConfig) constructMcpSseStatefulSessionEnvoyFilter(route *common.
 		},
 		Patch: &networking.EnvoyFilter_Patch{
 			Operation: networking.EnvoyFilter_Patch_MERGE,
-			Value: buildPatchStruct(`{
+			Value: buildPatchStruct(fmt.Sprintf(`{
 				"typed_per_filter_config": {
 					"envoy.filters.http.mcp_sse_stateful_session": {
 						"@type": "type.googleapis.com/udpa.type.v1.TypedStruct",
@@ -2023,7 +2023,7 @@ func (m *IngressConfig) constructMcpSseStatefulSessionEnvoyFilter(route *common.
 										"@type": "type.googleapis.com/udpa.type.v1.TypedStruct",
 										"type_url": "type.googleapis.com/envoy.extensions.http.mcp_sse_stateful_session.envelope.v3alpha.EnvelopeSessionState",
 										"value": {
-											"param_name": "sessionId",
+											"param_name": "%s",
 											"chunk_end_patterns": ["\r\n\r\n", "\n\n", "\r\r"]
 										}
 									}
@@ -2033,7 +2033,7 @@ func (m *IngressConfig) constructMcpSseStatefulSessionEnvoyFilter(route *common.
 						}
 					}
 				}
-			}`),
+			}`, mcpSseStatefulKey)),
 		},
 	})
 
diff --git a/pkg/ingress/kube/annotations/loadbalance.go b/pkg/ingress/kube/annotations/loadbalance.go
index 93a4e3cc5..6cc088cc8 100644
--- a/pkg/ingress/kube/annotations/loadbalance.go
+++ b/pkg/ingress/kube/annotations/loadbalance.go
@@ -41,6 +41,9 @@ const (
 
 	defaultAffinityCookieName = "INGRESSCOOKIE"
 	defaultAffinityCookiePath = "/"
+
+	mcpSseStatefulKey        = "mcp-sse-stateful-param-name"
+	defaultMcpSseStatefulKey = "sessionId"
 )
 
 var (
@@ -66,10 +69,11 @@ type consistentHashByCookie struct {
 }
 
 type LoadBalanceConfig struct {
-	simple         networking.LoadBalancerSettings_SimpleLB
-	other          *consistentHashByOther
-	cookie         *consistentHashByCookie
-	McpSseStateful bool
+	simple            networking.LoadBalancerSettings_SimpleLB
+	other             *consistentHashByOther
+	cookie            *consistentHashByCookie
+	McpSseStateful    bool
+	McpSseStatefulKey string
 }
 
 type loadBalance struct{}
@@ -139,6 +143,11 @@ func (l loadBalance) Parse(annotations Annotations, config *Ingress, _ *GlobalCo
 			lb = strings.ToUpper(lb)
 			if lb == "MCP-SSE" {
 				loadBalanceConfig.McpSseStateful = true
+				if key, err := annotations.ParseStringASAP(mcpSseStatefulKey); err == nil {
+					loadBalanceConfig.McpSseStatefulKey = key
+				} else {
+					loadBalanceConfig.McpSseStatefulKey = defaultMcpSseStatefulKey
+				}
 			} else {
 				loadBalanceConfig.simple = networking.LoadBalancerSettings_SimpleLB(networking.LoadBalancerSettings_SimpleLB_value[lb])
 			}