fix: stable filter name

kontrol-service/engine/flow/render.go

@@ -2,7 +2,7 @@ package flow
 
 import (
 	"fmt"
-	"hash/fnv"
+	"regexp"
 	"slices"
 	"strings"
 
@@ -434,8 +434,11 @@ func getIngresses(
 							newPaths = append(newPaths, path)
 
 							// Set Envoy FIlter for the service
-							luaFilterFrontend := generateDynamicLuaScript(allServices, activeFlowID, namespace, hostnames)
-							inboundFilter := getInboundFilter(target.ServiceID, namespace, -1, &target.Version, &luaFilterFrontend)
+							filter := &externalInboudFilter{
+								filter: generateDynamicLuaScript(allServices, activeFlowID, namespace, hostnames),
+								name:   strings.Join(hostnames, "-"),
+							}
+							inboundFilter := getInboundFilter(target.ServiceID, namespace, -1, &target.Version, filter)
 							logrus.Debugf("Adding inbound filter to setup routing table for flow '%s' on service '%s', version '%s'", activeFlowID, target.ServiceID, target.Version)
 							filters = append(filters, inboundFilter)
 						}
@@ -497,8 +500,11 @@ func getHTTPRoutes(
 
 							hostnames := lo.Map(routeSpec.Hostnames, func(item gateway.Hostname, _ int) string { return string(item) })
 							// Set Envoy FIlter for the service
-							luaFilterFrontend := generateDynamicLuaScript(allServices, activeFlowID, namespace, hostnames)
-							inboundFilter := getInboundFilter(target.ServiceID, namespace, -1, &target.Version, &luaFilterFrontend)
+							filter := &externalInboudFilter{
+								filter: generateDynamicLuaScript(allServices, activeFlowID, namespace, hostnames),
+								name:   strings.Join(hostnames, "-"),
+							}
+							inboundFilter := getInboundFilter(target.ServiceID, namespace, -1, &target.Version, filter)
 							logrus.Debugf("Adding inbound filter to setup routing table for flow '%s' on service '%s', version '%s'", activeFlowID, target.ServiceID, target.Version)
 							filters = append(filters, inboundFilter)
 						}
@@ -540,7 +546,6 @@ func getEnvoyFilters(
 	targetServices []string,
 ) []istioclient.EnvoyFilter {
 	filters := []istioclient.EnvoyFilter{}
-	traceIdEnforcerLuaScript := generateTraceIDEnforcerLuaScript()
 
 	// HttpRoute (workload) are applied at the serviceID level, not the serviceID-version level
 	groupedServices := lo.GroupBy(allServices, func(item *resolved.Service) string { return item.ServiceID })
@@ -562,11 +567,11 @@ func getEnvoyFilters(
 		// more inbound EnvoyFilters for routing routing traffic on frontend services are added by the getHTTPRoutes function
 		if isTargertService {
 			logrus.Debugf("Adding inbound filter to enforce trace IDs for service '%s'", serviceID)
-			inboundFilter := getInboundFilter(serviceID, namespace, 0, nil, &traceIdEnforcerLuaScript)
+			inboundFilter := getInboundFilter(serviceID, namespace, 0, nil, &traceIdEnforcer{})
 			filters = append(filters, inboundFilter)
 		} else {
 			logrus.Debugf("Adding inbound filter for inner service '%s'", serviceID)
-			inboundFilter := getInboundFilter(serviceID, namespace, 0, nil, nil)
+			inboundFilter := getInboundFilter(serviceID, namespace, 0, nil, &innerInboundFilter{})
 			filters = append(filters, inboundFilter)
 		}
 
@@ -577,28 +582,58 @@ func getEnvoyFilters(
 	return filters
 }
 
-func getInboundFilter(serviceID, namespace string, priority int32, versionSelector, luaFilterFrontend *string) istioclient.EnvoyFilter {
+type luaFilter interface {
+	getName() string
+	getFilter() string
+}
+
+type innerInboundFilter struct{}
+
+type externalInboudFilter struct {
+	filter string
+	name   string
+}
+
+type traceIdEnforcer struct{}
+
+func (f *innerInboundFilter) getName() string {
+	return "inbound-router"
+}
+
+func (f *innerInboundFilter) getFilter() string {
+	return inboundRequestTraceIDFilter
+}
+
+func (f *externalInboudFilter) getName() string {
+	id := regexp.MustCompile(`[^a-z0-9.-]`).ReplaceAllString(f.name, "")
+	return "inbound-router-" + id + "-external"
+}
+
+func (f *externalInboudFilter) getFilter() string {
+	return f.filter
+}
+
+func (f *traceIdEnforcer) getName() string {
+	return "trace-id-enforcer"
+}
+
+func (f *traceIdEnforcer) getFilter() string {
+	return generateTraceIDEnforcerLuaScript()
+}
+
+func getInboundFilter(serviceID, namespace string, priority int32, versionSelector *string, luaFilter luaFilter) istioclient.EnvoyFilter {
 	labelSelector := map[string]string{
 		"app": serviceID,
 	}
 	if versionSelector != nil {
 		labelSelector["version"] = *versionSelector
 	}
 
-	var filterHashStr *string
-	luaFilter := inboundRequestTraceIDFilter
-	if luaFilterFrontend != nil {
-		luaFilter = *luaFilterFrontend
-
-		hash := fnv.New32a()
-		hash.Write([]byte(*luaFilterFrontend))
-		hashStr := fmt.Sprintf("%d", hash.Sum32())
-		filterHashStr = &hashStr
-
+	if luaFilter == nil {
+		luaFilter = &innerInboundFilter{}
 	}
-
-	idStr := "inbound-router"
-	ids := []*string{&serviceID, &idStr, versionSelector, filterHashStr}
+	filterName := luaFilter.getName()
+	ids := []*string{&serviceID, versionSelector, &filterName}
 	name := strings.Join(lo.FilterMap(ids, func(id *string, _ int) (string, bool) {
 		if id != nil {
 			return *id, true
@@ -646,7 +681,7 @@ func getInboundFilter(serviceID, namespace string, priority int32, versionSelect
 										StructValue: &structpb.Struct{
 											Fields: map[string]*structpb.Value{
 												"@type":      {Kind: &structpb.Value_StringValue{StringValue: luaFilterType}},
-												"inlineCode": {Kind: &structpb.Value_StringValue{StringValue: luaFilter}},
+												"inlineCode": {Kind: &structpb.Value_StringValue{StringValue: luaFilter.getFilter()}},
 											},
 										},
 									},