feat: add callback for route configurations. (#10728)

Co-authored-by: Nathan Fudenberg <[email protected]>

Author: yuval-k

internal/kgateway/extensions2/plugins/backend/plugin.go

@@ -84,6 +84,7 @@ func (u *BackendIr) Equals(other any) bool {
 }
 
 type backendPlugin struct {
+	ir.UnimplementedProxyTranslationPass
 	needFilter map[string]bool
 }
 

internal/kgateway/extensions2/plugins/directresponse/direct_response_plugin.go

@@ -46,6 +46,7 @@ func (d *directResponse) Equals(in any) bool {
 }
 
 type directResponsePluginGwPass struct {
+	ir.UnimplementedProxyTranslationPass
 }
 
 func (p *directResponsePluginGwPass) ApplyHCM(ctx context.Context, pCtx *ir.HcmContext, out *envoyhttp.HttpConnectionManager) error {

internal/kgateway/extensions2/plugins/httplistenerpolicy/httplistener_plugin.go

@@ -56,6 +56,7 @@ func (d *httpListenerPolicy) Equals(in any) bool {
 }
 
 type httpListenerPolicyPluginGwPass struct {
+	ir.UnimplementedProxyTranslationPass
 }
 
 func (p *httpListenerPolicyPluginGwPass) ApplyListenerPlugin(ctx context.Context, pCtx *ir.ListenerContext, out *envoy_config_listener_v3.Listener) {

internal/kgateway/extensions2/plugins/listenerpolicy/listener_policy_plugin.go

@@ -39,6 +39,7 @@ func (d *listenerPolicy) Equals(in any) bool {
 }
 
 type listenerPolicyPluginGwPass struct {
+	ir.UnimplementedProxyTranslationPass
 }
 
 func NewPlugin(ctx context.Context, commoncol *common.CommonCollections) extensionplug.Plugin {

internal/kgateway/extensions2/plugins/routepolicy/route_policy_plugin.go

@@ -39,6 +39,7 @@ func (d *routePolicy) Equals(in any) bool {
 }
 
 type routePolicyPluginGwPass struct {
+	ir.UnimplementedProxyTranslationPass
 }
 
 func (p *routePolicyPluginGwPass) ApplyHCM(ctx context.Context, pCtx *ir.HcmContext, out *envoyhttp.HttpConnectionManager) error {

internal/kgateway/ir/iface.go

@@ -18,6 +18,12 @@ import (
 type ListenerContext struct {
 	Policy PolicyIR
 }
+
+type RouteConfigContext struct {
+	// No policy here, as you can't attach policies to route configs.
+	// we will call every policy with this to set defaults.
+}
+
 type VirtualHostContext struct {
 	Policy PolicyIR
 }
@@ -57,6 +63,12 @@ type ProxyTranslationPass interface {
 		pCtx *HcmContext,
 		out *envoy_hcm.HttpConnectionManager) error
 
+	// called 1 time for all the routes in a filter chain.
+	ApplyRouteConfigPlugin(
+		ctx context.Context,
+		pCtx *RouteConfigContext,
+		out *envoy_config_route_v3.RouteConfiguration,
+	)
 	ApplyVhostPlugin(
 		ctx context.Context,
 		pCtx *VirtualHostContext,
@@ -83,6 +95,39 @@ type ProxyTranslationPass interface {
 	ResourcesToAdd(ctx context.Context) Resources
 }
 
+type UnimplementedProxyTranslationPass struct{}
+
+var _ ProxyTranslationPass = UnimplementedProxyTranslationPass{}
+
+func (s UnimplementedProxyTranslationPass) ApplyListenerPlugin(ctx context.Context, pCtx *ListenerContext, out *envoy_config_listener_v3.Listener) {
+}
+func (s UnimplementedProxyTranslationPass) ApplyHCM(ctx context.Context, pCtx *HcmContext, out *envoy_hcm.HttpConnectionManager) error {
+	return nil
+}
+func (s UnimplementedProxyTranslationPass) ApplyRouteConfigPlugin(ctx context.Context, pCtx *RouteConfigContext, out *envoy_config_route_v3.RouteConfiguration) {
+}
+
+func (s UnimplementedProxyTranslationPass) ApplyVhostPlugin(ctx context.Context, pCtx *VirtualHostContext, out *envoy_config_route_v3.VirtualHost) {
+}
+func (s UnimplementedProxyTranslationPass) ApplyForRoute(ctx context.Context, pCtx *RouteContext, out *envoy_config_route_v3.Route) error {
+	return nil
+}
+func (s UnimplementedProxyTranslationPass) ApplyForRouteBackend(ctx context.Context, policy PolicyIR, pCtx *RouteBackendContext) error {
+	return nil
+}
+func (s UnimplementedProxyTranslationPass) HttpFilters(ctx context.Context, fc FilterChainCommon) ([]plugins.StagedHttpFilter, error) {
+	return nil, nil
+}
+func (s UnimplementedProxyTranslationPass) UpstreamHttpFilters(ctx context.Context) ([]plugins.StagedUpstreamHttpFilter, error) {
+	return nil, nil
+}
+func (s UnimplementedProxyTranslationPass) NetworkFilters(ctx context.Context) ([]plugins.StagedNetworkFilter, error) {
+	return nil, nil
+}
+func (s UnimplementedProxyTranslationPass) ResourcesToAdd(ctx context.Context) Resources {
+	return Resources{}
+}
+
 type Resources struct {
 	Clusters []envoy_config_cluster_v3.Cluster
 }

internal/kgateway/krtcollections/builtin.go

@@ -45,17 +45,10 @@ func (d *builtinPlugin) Equals(in any) bool {
 	// we don't really need equality check here, because this policy is embedded in the httproute,
 	// and we have generation based equality checks for that already.
 	return true
-	// d2, ok := in.(*builtinPlugin)
-	//
-	//	if !ok {
-	//		return false
-	//	}
-	//
-	// // TODO: implement equality check
-	// return d.spec == d2.spec
 }
 
 type builtinPluginGwPass struct {
+	ir.UnimplementedProxyTranslationPass
 }
 
 func (p *builtinPluginGwPass) ApplyHCM(ctx context.Context, pCtx *ir.HcmContext, out *envoyhttp.HttpConnectionManager) error {

internal/kgateway/translator/irtranslator/route.go

@@ -36,10 +36,17 @@ type httpRouteConfigurationTranslator struct {
 func (h *httpRouteConfigurationTranslator) ComputeRouteConfiguration(ctx context.Context, vhosts []*ir.VirtualHost) *envoy_config_route_v3.RouteConfiguration {
 	ctx = contextutils.WithLogger(ctx, "compute_route_config."+h.routeConfigName)
 	cfg := &envoy_config_route_v3.RouteConfiguration{
-		Name:         h.routeConfigName,
-		VirtualHosts: h.computeVirtualHosts(ctx, vhosts),
+		Name: h.routeConfigName,
 		//		MaxDirectResponseBodySizeBytes: h.parentListener.GetRouteOptions().GetMaxDirectResponseBodySizeBytes(),
 	}
+	for _, pass := range h.PluginPass {
+		if pass == nil {
+			continue
+		}
+		pass.ApplyRouteConfigPlugin(ctx, &ir.RouteConfigContext{}, cfg)
+	}
+	cfg.VirtualHosts = h.computeVirtualHosts(ctx, vhosts)
+
 	// Gateway API spec requires that port values in HTTP Host headers be ignored when performing a match
 	// See https://gateway-api.sigs.k8s.io/reference/spec/#gateway.networking.k8s.io/v1.HTTPRouteSpec - hostnames field
 	cfg.IgnorePortInHostMatching = true
@@ -94,20 +101,6 @@ func (h *httpRouteConfigurationTranslator) computeVirtualHost(
 
 	// run the http plugins that are attached to the listener or gateway on the virtual host
 	h.runVhostPlugins(ctx, out)
-	for gvk, pols := range h.listener.AttachedPolicies.Policies {
-		pass := h.PluginPass[gvk]
-		if pass == nil {
-			// TODO: should never happen, log error and report condition
-			continue
-		}
-		for _, pol := range pols {
-			pctx := &ir.VirtualHostContext{
-				Policy: pol.PolicyIr,
-			}
-			pass.ApplyVhostPlugin(ctx, pctx, out)
-			// TODO: check return value, if error returned, log error and report condition
-		}
-	}
 
 	return out
 }