xds/internal/xdsclient: Add support for String Matcher Header Matcher…

… in RDS (#6313)

internal/xds/matcher/matcher_header.go

@@ -241,3 +241,34 @@ func (hcm *HeaderContainsMatcher) Match(md metadata.MD) bool {
 func (hcm *HeaderContainsMatcher) String() string {
 	return fmt.Sprintf("headerContains:%v%v", hcm.key, hcm.contains)
 }
+
+// HeaderStringMatcher matches on whether the header value matches against the
+// StringMatcher specified.
+type HeaderStringMatcher struct {
+	key           string
+	stringMatcher StringMatcher
+	invert        bool
+}
+
+// NewHeaderStringMatcher returns a new HeaderStringMatcher.
+func NewHeaderStringMatcher(key string, sm StringMatcher, invert bool) *HeaderStringMatcher {
+	return &HeaderStringMatcher{
+		key:           key,
+		stringMatcher: sm,
+		invert:        invert,
+	}
+}
+
+// Match returns whether the passed in HTTP Headers match according to the
+// specified StringMatcher.
+func (hsm *HeaderStringMatcher) Match(md metadata.MD) bool {
+	v, ok := mdValuesFromOutgoingCtx(md, hsm.key)
+	if !ok {
+		return false
+	}
+	return hsm.stringMatcher.Match(v) != hsm.invert
+}
+
+func (hsm *HeaderStringMatcher) String() string {
+	return fmt.Sprintf("headerString:%v:%v", hsm.key, hsm.stringMatcher)
+}

internal/xds/matcher/matcher_header_test.go

@@ -467,3 +467,83 @@ func TestHeaderSuffixMatcherMatch(t *testing.T) {
 		})
 	}
 }
+
+func TestHeaderStringMatch(t *testing.T) {
+	tests := []struct {
+		name   string
+		key    string
+		sm     StringMatcher
+		invert bool
+		md     metadata.MD
+		want   bool
+	}{
+		{
+			name: "should-match",
+			key:  "th",
+			sm: StringMatcher{
+				exactMatch: newStringP("tv"),
+			},
+			invert: false,
+			md:     metadata.Pairs("th", "tv"),
+			want:   true,
+		},
+		{
+			name: "not match",
+			key:  "th",
+			sm: StringMatcher{
+				containsMatch: newStringP("tv"),
+			},
+			invert: false,
+			md:     metadata.Pairs("th", "not-match"),
+			want:   false,
+		},
+		{
+			name: "invert string match",
+			key:  "th",
+			sm: StringMatcher{
+				containsMatch: newStringP("tv"),
+			},
+			invert: true,
+			md:     metadata.Pairs("th", "not-match"),
+			want:   true,
+		},
+		{
+			name: "header missing",
+			key:  "th",
+			sm: StringMatcher{
+				containsMatch: newStringP("tv"),
+			},
+			invert: false,
+			md:     metadata.Pairs("not-specified-key", "not-match"),
+			want:   false,
+		},
+		{
+			name: "header missing invert true",
+			key:  "th",
+			sm: StringMatcher{
+				containsMatch: newStringP("tv"),
+			},
+			invert: true,
+			md:     metadata.Pairs("not-specified-key", "not-match"),
+			want:   false,
+		},
+		{
+			name: "header empty string invert",
+			key:  "th",
+			sm: StringMatcher{
+				containsMatch: newStringP("tv"),
+			},
+			invert: true,
+			md:     metadata.Pairs("th", ""),
+			want:   true,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			hsm := NewHeaderStringMatcher(test.key, test.sm, test.invert)
+			if got := hsm.Match(test.md); got != test.want {
+				t.Errorf("match() = %v, want %v", got, test.want)
+			}
+		})
+	}
+}

xds/internal/xdsclient/xdsresource/matcher.go

@@ -59,6 +59,8 @@ func RouteToMatcher(r *Route) (*CompositeMatcher, error) {
 			matcherT = matcher.NewHeaderRangeMatcher(h.Name, h.RangeMatch.Start, h.RangeMatch.End, invert)
 		case h.PresentMatch != nil:
 			matcherT = matcher.NewHeaderPresentMatcher(h.Name, *h.PresentMatch, invert)
+		case h.StringMatch != nil:
+			matcherT = matcher.NewHeaderStringMatcher(h.Name, *h.StringMatch, invert)
 		default:
 			return nil, fmt.Errorf("illegal route: missing header_match_specifier")
 		}

xds/internal/xdsclient/xdsresource/type_rds.go

@@ -171,6 +171,7 @@ type HeaderMatcher struct {
 	SuffixMatch  *string
 	RangeMatch   *Int64Range
 	PresentMatch *bool
+	StringMatch  *matcher.StringMatcher
 }
 
 // Int64Range is a range for header range match.

xds/internal/xdsclient/xdsresource/unmarshal_rds.go

@@ -24,13 +24,15 @@ import (
 	"strings"
 	"time"
 
-	v3routepb "github.com/envoyproxy/go-control-plane/envoy/config/route/v3"
-	v3typepb "github.com/envoyproxy/go-control-plane/envoy/type/v3"
 	"github.com/golang/protobuf/proto"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/internal/envconfig"
+	"google.golang.org/grpc/internal/xds/matcher"
 	"google.golang.org/grpc/xds/internal/clusterspecifier"
 	"google.golang.org/protobuf/types/known/anypb"
+
+	v3routepb "github.com/envoyproxy/go-control-plane/envoy/config/route/v3"
+	v3typepb "github.com/envoyproxy/go-control-plane/envoy/type/v3"
 )
 
 func unmarshalRouteConfigResource(r *anypb.Any) (string, RouteConfigUpdate, error) {
@@ -273,6 +275,12 @@ func routesProtoToSlice(routes []*v3routepb.Route, csps map[string]clusterspecif
 				header.PrefixMatch = &ht.PrefixMatch
 			case *v3routepb.HeaderMatcher_SuffixMatch:
 				header.SuffixMatch = &ht.SuffixMatch
+			case *v3routepb.HeaderMatcher_StringMatch:
+				sm, err := matcher.StringMatcherFromProto(ht.StringMatch)
+				if err != nil {
+					return nil, nil, fmt.Errorf("route %+v has an invalid string matcher: %v", err, ht.StringMatch)
+				}
+				header.StringMatch = &sm
 			default:
 				return nil, nil, fmt.Errorf("route %+v has an unrecognized header matcher: %+v", r, ht)
 			}

xds/internal/xdsclient/xdsresource/unmarshal_rds_test.go

@@ -33,6 +33,7 @@ import (
 	"google.golang.org/grpc/internal/envconfig"
 	"google.golang.org/grpc/internal/pretty"
 	"google.golang.org/grpc/internal/testutils"
+	"google.golang.org/grpc/internal/xds/matcher"
 	"google.golang.org/grpc/xds/internal/clusterspecifier"
 	"google.golang.org/grpc/xds/internal/httpfilter"
 	"google.golang.org/grpc/xds/internal/xdsclient/xdsresource/version"
@@ -923,6 +924,7 @@ func (s) TestUnmarshalRouteConfig(t *testing.T) {
 }
 
 func (s) TestRoutesProtoToSlice(t *testing.T) {
+	sm, _ := matcher.StringMatcherFromProto(&v3matcherpb.StringMatcher{MatchPattern: &v3matcherpb.StringMatcher_Exact{Exact: "tv"}})
 	var (
 		goodRouteWithFilterConfigs = func(cfgs map[string]*anypb.Any) []*v3routepb.Route {
 			// Sets per-filter config in cluster "B" and in the route.
@@ -1085,6 +1087,51 @@ func (s) TestRoutesProtoToSlice(t *testing.T) {
 			}},
 			wantErr: false,
 		},
+		{
+			name: "good with string matcher",
+			routes: []*v3routepb.Route{
+				{
+					Match: &v3routepb.RouteMatch{
+						PathSpecifier: &v3routepb.RouteMatch_SafeRegex{SafeRegex: &v3matcherpb.RegexMatcher{Regex: "/a/"}},
+						Headers: []*v3routepb.HeaderMatcher{
+							{
+								Name:                 "th",
+								HeaderMatchSpecifier: &v3routepb.HeaderMatcher_StringMatch{StringMatch: &v3matcherpb.StringMatcher{MatchPattern: &v3matcherpb.StringMatcher_Exact{Exact: "tv"}}},
+							},
+						},
+						RuntimeFraction: &v3corepb.RuntimeFractionalPercent{
+							DefaultValue: &v3typepb.FractionalPercent{
+								Numerator:   1,
+								Denominator: v3typepb.FractionalPercent_HUNDRED,
+							},
+						},
+					},
+					Action: &v3routepb.Route_Route{
+						Route: &v3routepb.RouteAction{
+							ClusterSpecifier: &v3routepb.RouteAction_WeightedClusters{
+								WeightedClusters: &v3routepb.WeightedCluster{
+									Clusters: []*v3routepb.WeightedCluster_ClusterWeight{
+										{Name: "B", Weight: &wrapperspb.UInt32Value{Value: 60}},
+										{Name: "A", Weight: &wrapperspb.UInt32Value{Value: 40}},
+									},
+								}}}},
+				},
+			},
+			wantRoutes: []*Route{{
+				Regex: func() *regexp.Regexp { return regexp.MustCompile("/a/") }(),
+				Headers: []*HeaderMatcher{
+					{
+						Name:        "th",
+						InvertMatch: newBoolP(false),
+						StringMatch: &sm,
+					},
+				},
+				Fraction:         newUInt32P(10000),
+				WeightedClusters: map[string]WeightedCluster{"A": {Weight: 40}, "B": {Weight: 60}},
+				ActionType:       RouteActionRoute,
+			}},
+			wantErr: false,
+		},
 		{
 			name: "query is ignored",
 			routes: []*v3routepb.Route{