istio: avoid copy virtual services for sidecar scope calculation

This CL patches commit e40f57e from
upstream istio into air-release-1.14.4 to improve propagation delay.

Original PR:
istio#41101

Change-Id: I7b0da42f591a6da9e20342235ccbf93f2741132b
Reviewed-on: https://gerrit.musta.ch/c/public/istio/+/3822
Reviewed-by: Weibo He <[email protected]>

pilot/pkg/model/push_context.go

@@ -876,6 +876,11 @@ func (ps *PushContext) IsServiceVisible(service *Service, namespace string) bool
 // VirtualServicesForGateway lists all virtual services bound to the specified gateways
 // This replaces store.VirtualServices. Used only by the gateways
 // Sidecars use the egressListener.VirtualServices().
+//
+// Note that for generating the imported virtual services of sidecar egress
+// listener, we don't call this function to copy configs for performance issues.
+// Instead, we pass the virtualServiceIndex directly into SelectVirtualServices
+// function.
 func (ps *PushContext) VirtualServicesForGateway(proxyNamespace, gateway string) []config.Config {
 	res := make([]config.Config, 0, len(ps.virtualServiceIndex.privateByNamespaceAndGateway[proxyNamespace][gateway])+
 		len(ps.virtualServiceIndex.exportedToNamespaceByGateway[proxyNamespace][gateway])+

pilot/pkg/model/sidecar.go

@@ -462,8 +462,7 @@ func convertIstioListenerToWrapper(ps *PushContext, configNamespace string,
 		out.listenerHosts[parts[0]] = append(out.listenerHosts[parts[0]], host.Name(parts[1]))
 	}
 
-	vses := ps.VirtualServicesForGateway(configNamespace, constants.IstioMeshGateway)
-	out.virtualServices = SelectVirtualServices(vses, out.listenerHosts)
+	out.virtualServices = SelectVirtualServices(ps.virtualServiceIndex, configNamespace, out.listenerHosts)
 	svces := ps.servicesExportedToNamespace(configNamespace)
 	out.services = out.selectServices(svces, configNamespace, out.listenerHosts)
 

pilot/pkg/model/virtualservice.go

@@ -30,8 +30,8 @@ import (
 )
 
 // SelectVirtualServices selects the virtual services by matching given services' host names.
-// This is a common function used by both sidecar converter and http route.
-func SelectVirtualServices(virtualServices []config.Config, hosts map[string][]host.Name) []config.Config {
+// This function is used by sidecar converter.
+func SelectVirtualServices(vsidx virtualServiceIndex, configNamespace string, hosts map[string][]host.Name) []config.Config {
 	importedVirtualServices := make([]config.Config, 0)
 
 	vsset := sets.New()
@@ -54,24 +54,31 @@ func SelectVirtualServices(virtualServices []config.Config, hosts map[string][]h
 			}
 		}
 	}
-	for _, c := range virtualServices {
-		configNamespace := c.Namespace
-		// Selection algorithm:
-		// virtualservices have a list of hosts in the API spec
-		// if any host in the list matches one service hostname, select the virtual service
-		// and break out of the loop.
 
-		// Check if there is an explicit import of form ns/* or ns/host
-		if importedHosts, nsFound := hosts[configNamespace]; nsFound {
-			addVirtualService(c, importedHosts)
-		}
+	loopAndAdd := func(vses []config.Config) {
+		for _, c := range vses {
+			configNamespace := c.Namespace
+			// Selection algorithm:
+			// virtualservices have a list of hosts in the API spec
+			// if any host in the list matches one service hostname, select the virtual service
+			// and break out of the loop.
+
+			// Check if there is an explicit import of form ns/* or ns/host
+			if importedHosts, nsFound := hosts[configNamespace]; nsFound {
+				addVirtualService(c, importedHosts)
+			}
 
-		// Check if there is an import of form */host or */*
-		if importedHosts, wnsFound := hosts[wildcardNamespace]; wnsFound {
-			addVirtualService(c, importedHosts)
+			// Check if there is an import of form */host or */*
+			if importedHosts, wnsFound := hosts[wildcardNamespace]; wnsFound {
+				addVirtualService(c, importedHosts)
+			}
 		}
 	}
 
+	loopAndAdd(vsidx.privateByNamespaceAndGateway[configNamespace][constants.IstioMeshGateway])
+	loopAndAdd(vsidx.exportedToNamespaceByGateway[configNamespace][constants.IstioMeshGateway])
+	loopAndAdd(vsidx.publicByGateway[constants.IstioMeshGateway])
+
 	return importedVirtualServices
 }
 

pilot/pkg/model/virtualservice_test.go

@@ -26,6 +26,7 @@ import (
 	networking "istio.io/api/networking/v1alpha3"
 	"istio.io/istio/pilot/pkg/serviceregistry/provider"
 	"istio.io/istio/pkg/config"
+	"istio.io/istio/pkg/config/constants"
 	"istio.io/istio/pkg/config/host"
 	"istio.io/istio/pkg/config/protocol"
 	"istio.io/istio/pkg/config/schema/collections"
@@ -2035,9 +2036,22 @@ func TestSelectVirtualService(t *testing.T) {
 		},
 		Spec: virtualServiceSpec7,
 	}
-	configs := SelectVirtualServices(
-		[]config.Config{virtualService1, virtualService2, virtualService3, virtualService4, virtualService5, virtualService6, virtualService7},
-		hostsByNamespace)
+
+	index := virtualServiceIndex{
+		publicByGateway: map[string][]config.Config{
+			constants.IstioMeshGateway: {
+				virtualService1,
+				virtualService2,
+				virtualService3,
+				virtualService4,
+				virtualService5,
+				virtualService6,
+				virtualService7,
+			},
+		},
+	}
+
+	configs := SelectVirtualServices(index, "some-ns", hostsByNamespace)
 	expectedVS := []string{virtualService1.Name, virtualService2.Name, virtualService4.Name, virtualService7.Name}
 	if len(expectedVS) != len(configs) {
 		t.Fatalf("Unexpected virtualService, got %d, epxected %d", len(configs), len(expectedVS))