snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

internal/xds/xdsclient/xdsresource/unmarshal_eds.go

@@ -0,0 +1,294 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xdsresource
+
+import (
+	"fmt"
+	"math"
+	"net"
+	"strconv"
+
+	v3corepb "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
+	v3endpointpb "github.com/envoyproxy/go-control-plane/envoy/config/endpoint/v3"
+	v3typepb "github.com/envoyproxy/go-control-plane/envoy/type/v3"
+	"google.golang.org/grpc/experimental/balancer/hostname"
+	"google.golang.org/grpc/internal/envconfig"
+	"google.golang.org/grpc/internal/pretty"
+	xdsinternal "google.golang.org/grpc/internal/xds"
+	"google.golang.org/grpc/internal/xds/clients"
+	"google.golang.org/grpc/resolver"
+	"google.golang.org/grpc/resolver/ringhash"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/anypb"
+)
+
+// Hostname returns the hostname from the BalancerAttributes of the
+// given Address. If this attribute is not set, it returns the empty
+// string.
+func Hostname(addr resolver.Address) string {
+	ep := resolver.Endpoint{Attributes: addr.BalancerAttributes}
+	return hostname.FromEndpoint(ep)
+}
+
+func unmarshalEndpointsResource(r *anypb.Any) (string, EndpointsUpdate, error) {
+	r, err := UnwrapResource(r)
+	if err != nil {
+		return "", EndpointsUpdate{}, fmt.Errorf("failed to unwrap resource: %v", err)
+	}
+
+	if !IsEndpointsResource(r.GetTypeUrl()) {
+		return "", EndpointsUpdate{}, fmt.Errorf("unexpected resource type: %q ", r.GetTypeUrl())
+	}
+
+	cla := &v3endpointpb.ClusterLoadAssignment{}
+	if err := proto.Unmarshal(r.GetValue(), cla); err != nil {
+		return "", EndpointsUpdate{}, fmt.Errorf("failed to unmarshal resource: %v", err)
+	}
+
+	if cla.GetClusterName() == "" {
+		return "", EndpointsUpdate{}, fmt.Errorf("empty resource name in endpoints resource")
+	}
+
+	u, err := parseEDSRespProto(cla)
+	if err != nil {
+		return cla.GetClusterName(), EndpointsUpdate{}, err
+	}
+	u.Raw = r
+
+	return cla.GetClusterName(), u, nil
+}
+
+func parseAddress(socketAddress *v3corepb.SocketAddress) string {
+	return net.JoinHostPort(socketAddress.GetAddress(), strconv.Itoa(int(socketAddress.GetPortValue())))
+}
+
+func parseDropPolicy(dropPolicy *v3endpointpb.ClusterLoadAssignment_Policy_DropOverload) (OverloadDropConfig, error) {
+	percentage := dropPolicy.GetDropPercentage()
+	var (
+		numerator   = percentage.GetNumerator()
+		denominator uint32
+	)
+	switch percentage.GetDenominator() {
+	case v3typepb.FractionalPercent_HUNDRED:
+		denominator = 100
+	case v3typepb.FractionalPercent_TEN_THOUSAND:
+		denominator = 10000
+	case v3typepb.FractionalPercent_MILLION:
+		denominator = 1000000
+	default:
+		return OverloadDropConfig{}, fmt.Errorf("EDS response contains a drop policy with unsupported denominator: %v", percentage.GetDenominator())
+	}
+	return OverloadDropConfig{
+		Category:    dropPolicy.GetCategory(),
+		Numerator:   numerator,
+		Denominator: denominator,
+	}, nil
+}
+
+func parseEndpoints(lbEndpoints []*v3endpointpb.LbEndpoint, uniqueEndpointAddrs map[string]bool) ([]Endpoint, error) {
+	endpoints := make([]Endpoint, 0, len(lbEndpoints))
+	var totalWeight uint64
+	for _, lbEndpoint := range lbEndpoints {
+		// If the load_balancing_weight field is specified, it must be set to a
+		// value of at least 1.  If unspecified, each host is presumed to have
+		// equal weight in a locality.
+		weight := uint32(1)
+		if w := lbEndpoint.GetLoadBalancingWeight(); w != nil {
+			if w.GetValue() == 0 {
+				return nil, fmt.Errorf("EDS response contains an endpoint with zero weight: %+v", lbEndpoint)
+			}
+			weight = w.GetValue()
+		}
+
+		totalWeight += uint64(weight)
+		if totalWeight > math.MaxUint32 {
+			return nil, fmt.Errorf("sum of weights of endpoints in the same locality exceeds maximum value %d", uint64(math.MaxUint32))
+		}
+
+		addrs := []string{parseAddress(lbEndpoint.GetEndpoint().GetAddress().GetSocketAddress())}
+		if envconfig.XDSDualstackEndpointsEnabled {
+			for _, sa := range lbEndpoint.GetEndpoint().GetAdditionalAddresses() {
+				addrs = append(addrs, parseAddress(sa.GetAddress().GetSocketAddress()))
+			}
+		}
+
+		address := []resolver.Address{}
+		for _, a := range addrs {
+			address = append(address, resolver.Address{Addr: a})
+			if uniqueEndpointAddrs[a] {
+				return nil, fmt.Errorf("duplicate endpoint with the same address %s", a)
+			}
+			uniqueEndpointAddrs[a] = true
+		}
+
+		var endpointMetadata map[string]any
+		var hashKey string
+		if envconfig.XDSHTTPConnectEnabled || !envconfig.XDSEndpointHashKeyBackwardCompat {
+			var err error
+			endpointMetadata, err = validateAndConstructMetadata(lbEndpoint.GetMetadata())
+			if err != nil {
+				return nil, err
+			}
+
+			// "The xDS resolver, described in A74, will be changed to set the hash_key
+			// endpoint attribute to the value of LbEndpoint.Metadata envoy.lb hash_key
+			// field, as described in Envoy's documentation for the ring hash load
+			// balancer." - A76
+			if !envconfig.XDSEndpointHashKeyBackwardCompat {
+				hashKey = hashKeyFromMetadata(endpointMetadata)
+			}
+		}
+		endpoint := resolver.Endpoint{Addresses: address}
+		endpoint = hostname.Set(endpoint, lbEndpoint.GetEndpoint().GetHostname())
+		endpoint = ringhash.SetHashKey(endpoint, hashKey)
+		endpoints = append(endpoints, Endpoint{
+			ResolverEndpoint: endpoint,
+			HealthStatus:     EndpointHealthStatus(lbEndpoint.GetHealthStatus()),
+			Weight:           weight,
+			Metadata:         endpointMetadata,
+		})
+	}
+	return endpoints, nil
+}
+
+// hashKey extracts and returns the hash key from the given endpoint metadata.
+// If no hash key is found, it returns an empty string.
+func hashKeyFromMetadata(metadata map[string]any) string {
+	envoyLB, ok := metadata["envoy.lb"].(StructMetadataValue)
+	if ok {
+		if h, ok := envoyLB.Data["hash_key"].(string); ok {
+			return h
+		}
+	}
+	return ""
+}
+
+func parseEDSRespProto(m *v3endpointpb.ClusterLoadAssignment) (EndpointsUpdate, error) {
+	ret := EndpointsUpdate{}
+	for _, dropPolicy := range m.GetPolicy().GetDropOverloads() {
+		drop, err := parseDropPolicy(dropPolicy)
+		if err != nil {
+			return EndpointsUpdate{}, err
+		}
+		ret.Drops = append(ret.Drops, drop)
+	}
+	priorities := make(map[uint32]map[string]bool)
+	sumOfWeights := make(map[uint32]uint64)
+	uniqueEndpointAddrs := make(map[string]bool)
+	for _, locality := range m.Endpoints {
+		l := locality.GetLocality()
+		if l == nil {
+			return EndpointsUpdate{}, fmt.Errorf("EDS response contains a locality without ID, locality: %+v", locality)
+		}
+		weight := locality.GetLoadBalancingWeight().GetValue()
+		if weight == 0 {
+			logger.Warningf("Ignoring locality %s with weight 0", pretty.ToJSON(l))
+			continue
+		}
+		priority := locality.GetPriority()
+		sumOfWeights[priority] += uint64(weight)
+		if sumOfWeights[priority] > math.MaxUint32 {
+			return EndpointsUpdate{}, fmt.Errorf("sum of weights of localities at the same priority %d exceeded maximal value", priority)
+		}
+		localitiesWithPriority := priorities[priority]
+		if localitiesWithPriority == nil {
+			localitiesWithPriority = make(map[string]bool)
+			priorities[priority] = localitiesWithPriority
+		}
+		lid := clients.Locality{
+			Region:  l.Region,
+			Zone:    l.Zone,
+			SubZone: l.SubZone,
+		}
+		lidStr := xdsinternal.LocalityString(lid)
+
+		// "Since an xDS configuration can place a given locality under multiple
+		// priorities, it is possible to see locality weight attributes with
+		// different values for the same locality." - A52
+		//
+		// This is handled in the client by emitting the locality weight
+		// specified for the priority it is specified in. If the same locality
+		// has a different weight in two priorities, each priority will specify
+		// a locality with the locality weight specified for that priority, and
+		// thus the subsequent tree of balancers linked to that priority will
+		// use that locality weight as well.
+		if localitiesWithPriority[lidStr] {
+			return EndpointsUpdate{}, fmt.Errorf("duplicate locality %s with the same priority %v", lidStr, priority)
+		}
+		localitiesWithPriority[lidStr] = true
+		endpoints, err := parseEndpoints(locality.GetLbEndpoints(), uniqueEndpointAddrs)
+		if err != nil {
+			return EndpointsUpdate{}, err
+		}
+		var localityMetadata map[string]any
+		if envconfig.XDSHTTPConnectEnabled {
+			var err error
+			localityMetadata, err = validateAndConstructMetadata(locality.GetMetadata())
+			if err != nil {
+				return EndpointsUpdate{}, err
+			}
+		}
+
+		ret.Localities = append(ret.Localities, Locality{
+			ID:        lid,
+			Endpoints: endpoints,
+			Weight:    weight,
+			Priority:  priority,
+			Metadata:  localityMetadata,
+		})
+	}
+	for i := 0; i < len(priorities); i++ {
+		if _, ok := priorities[uint32(i)]; !ok {
+			return EndpointsUpdate{}, fmt.Errorf("priority %v missing (with different priorities %v received)", i, priorities)
+		}
+	}
+	return ret, nil
+}
+
+// validateAndConstructMetadata processes the metadata from the xDS resource
+// and returns a map of parsed metadata values.
+func validateAndConstructMetadata(metadataProto *v3corepb.Metadata) (map[string]any, error) {
+	if metadataProto == nil {
+		return nil, nil
+	}
+	metadata := make(map[string]any)
+	// First go through TypedFilterMetadata.
+	for key, anyProto := range metadataProto.GetTypedFilterMetadata() {
+		converter := metadataConverterForType(anyProto.GetTypeUrl())
+		// Ignore types we don't have a converter for.
+		if converter == nil {
+			continue
+		}
+		val, err := converter.convert(anyProto)
+		if err != nil {
+			// If the converter fails, nack the whole resource.
+			return nil, fmt.Errorf("metadata conversion for key %q and type %q failed: %v", key, anyProto.GetTypeUrl(), err)
+		}
+		metadata[key] = val
+	}
+
+	// Process FilterMetadata for any keys not already handled.
+	for key, structProto := range metadataProto.GetFilterMetadata() {
+		// Skip keys already added from TypedFilterMetadata.
+		if metadata[key] != nil {
+			continue
+		}
+		metadata[key] = StructMetadataValue{Data: structProto.AsMap()}
+	}
+	return metadata, nil
+}