From f2a585e950928ecae5fa69637f7b947f13e6f457 Mon Sep 17 00:00:00 2001
From: Denis Tingaikin <denis.tingajkin@xored.com>
Date: Mon, 2 Oct 2023 13:32:15 +0300
Subject: [PATCH] do not choose endpoints that doesn't match with the network
 service (#1516)

Signed-off-by: Denis Tingaikin <denis.tingajkin@xored.com>
---
 .../common/discover/server_test.go            | 98 +++++++++++++++++++
 pkg/tools/matchutils/utils.go                 |  7 +-
 2 files changed, 103 insertions(+), 2 deletions(-)

diff --git a/pkg/networkservice/common/discover/server_test.go b/pkg/networkservice/common/discover/server_test.go
index 4d3055121..9095544f9 100644
--- a/pkg/networkservice/common/discover/server_test.go
+++ b/pkg/networkservice/common/discover/server_test.go
@@ -1,5 +1,7 @@
 // Copyright (c) 2020-2022 Doc.ai and/or its affiliates.
 //
+// Copyright (c) 2023 Cisco and/or its affiliates.
+//
 // SPDX-License-Identifier: Apache-2.0
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -36,6 +38,7 @@ import (
 	registryadapters "github.com/networkservicemesh/sdk/pkg/registry/core/adapters"
 	registrynext "github.com/networkservicemesh/sdk/pkg/registry/core/next"
 	"github.com/networkservicemesh/sdk/pkg/tools/clienturlctx"
+	"github.com/networkservicemesh/sdk/pkg/tools/matchutils"
 )
 
 const (
@@ -543,3 +546,98 @@ func TestDiscoverCandidatesServer_NoEndpointOnClose(t *testing.T) {
 
 	require.True(t, closed)
 }
+
+func Test_Discover_Scale_FromZero_vL3(t *testing.T) {
+	var ns = &registry.NetworkService{
+		Name:    "ns-1",
+		Payload: "IP",
+		Matches: []*registry.Match{
+			{
+				Fallthrough: true,
+				Routes: []*registry.Destination{
+					{
+						DestinationSelector: map[string]string{
+							"app":      "nse-vl3-vpp",
+							"nodeName": "{{.nodeName}}",
+						},
+					},
+				},
+			},
+			{
+				Fallthrough: true,
+				SourceSelector: map[string]string{
+					"capability": "vl3",
+				},
+				Routes: []*registry.Destination{
+					{
+						DestinationSelector: map[string]string{
+							"capability": "vl3",
+						},
+					},
+				},
+			},
+			{
+				Fallthrough: true,
+				Routes: []*registry.Destination{
+					{
+						DestinationSelector: map[string]string{
+							"app": "nse-autoscaler",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var nseA = &registry.NetworkServiceEndpoint{
+		Name: "nse-A",
+		NetworkServiceLabels: map[string]*registry.NetworkServiceLabels{
+			"ns-1": {Labels: map[string]string{
+				"capability": "vl3",
+				"nodeName":   "node-1",
+				"app":        "nse-vl3-vpp",
+			}},
+		},
+	}
+
+	var nseB = &registry.NetworkServiceEndpoint{
+		Name: "nse-B",
+		NetworkServiceLabels: map[string]*registry.NetworkServiceLabels{
+			"ns-1": {Labels: map[string]string{
+				"capability": "vl3",
+				"nodeName":   "node-2",
+				"app":        "nse-vl3-vpp",
+			}},
+		},
+	}
+
+	var nseC = &registry.NetworkServiceEndpoint{
+		Name: "nse-C",
+		NetworkServiceLabels: map[string]*registry.NetworkServiceLabels{
+			"ns-1": {Labels: map[string]string{
+				"app": "nse-autoscaler",
+			}},
+		},
+	}
+
+	var nseD = &registry.NetworkServiceEndpoint{
+		Name: "nse-D",
+		NetworkServiceLabels: map[string]*registry.NetworkServiceLabels{
+			"ns-1": {Labels: map[string]string{
+				"app": "unknown",
+			}},
+		},
+	}
+
+	require.Empty(t, matchutils.MatchEndpoint(map[string]string{}, ns, nseD), "there are no matches for nse-D")
+	require.Empty(t, matchutils.MatchEndpoint(map[string]string{"app": "nse-autoscaler"}, ns, nseD), "there are no matches for nse-D")
+
+	require.Equal(t, []*registry.NetworkServiceEndpoint{nseC}, matchutils.MatchEndpoint(map[string]string{}, ns, nseC, nseD), "by match №3")
+	require.Equal(t, []*registry.NetworkServiceEndpoint{nseC}, matchutils.MatchEndpoint(map[string]string{"app": "nse-autoscaler"}, ns, nseC, nseD), "by match №3")
+
+	require.Equal(t, []*registry.NetworkServiceEndpoint{nseB}, matchutils.MatchEndpoint(map[string]string{"app": "nse-vl3-vpp", "nodeName": "node-2"}, ns, nseC, nseA, nseB, nseD), "by match №1")
+	require.Equal(t, []*registry.NetworkServiceEndpoint{nseA}, matchutils.MatchEndpoint(map[string]string{"app": "nse-vl3-vpp", "nodeName": "node-1"}, ns, nseC, nseA, nseD, nseB), "by match №1")
+
+	require.Equal(t, []*registry.NetworkServiceEndpoint{nseA}, matchutils.MatchEndpoint(map[string]string{"capability": "vl3", "app": "nse-vl3-vpp", "nodeName": "node-2"}, ns, nseC, nseA, nseD), "by match №2")
+	require.Equal(t, []*registry.NetworkServiceEndpoint{nseB}, matchutils.MatchEndpoint(map[string]string{"capability": "vl3", "app": "nse-vl3-vpp", "nodeName": "node-1"}, ns, nseC, nseD, nseB), "by match №2")
+}
diff --git a/pkg/tools/matchutils/utils.go b/pkg/tools/matchutils/utils.go
index 335a77d60..45fb5ebbc 100644
--- a/pkg/tools/matchutils/utils.go
+++ b/pkg/tools/matchutils/utils.go
@@ -34,6 +34,9 @@ import (
 // MatchEndpoint filters input nses by network service configuration.
 // Returns the same nses list if no matches are declared in the network service.
 func MatchEndpoint(nsLabels map[string]string, ns *registry.NetworkService, nses ...*registry.NetworkServiceEndpoint) []*registry.NetworkServiceEndpoint {
+	if len(ns.Matches) == 0 {
+		return nses
+	}
 	for _, match := range ns.GetMatches() {
 		// All match source selector labels should be present in the requested labels map
 		if !IsSubset(nsLabels, match.GetSourceSelector(), nsLabels) {
@@ -60,13 +63,13 @@ func MatchEndpoint(nsLabels map[string]string, ns *registry.NetworkService, nses
 		}
 
 		if match.GetMetadata() != nil && len(match.Routes) == 0 && len(nseCandidates) == 0 {
-			break
+			return nses
 		}
 
 		return nseCandidates
 	}
 
-	return nses
+	return nil
 }
 
 // MatchNetworkServices returns true if two network services are matched