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

internal/xds/clusterspecifier/cluster_specifier.go

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+/*
+ *
+ * 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 clusterspecifier contains the ClusterSpecifier interface and a registry for
+// storing and retrieving their implementations.
+package clusterspecifier
+
+import (
+	"google.golang.org/protobuf/proto"
+)
+
+// BalancerConfig is the Go Native JSON representation of a balancer
+// configuration.
+type BalancerConfig []map[string]any
+
+// ClusterSpecifier defines the parsing functionality of a Cluster Specifier.
+type ClusterSpecifier interface {
+	// TypeURLs are the proto message types supported by this
+	// ClusterSpecifierPlugin. A ClusterSpecifierPlugin will be registered by
+	// each of its supported message types.
+	TypeURLs() []string
+	// ParseClusterSpecifierConfig parses the provided configuration
+	// proto.Message from the top level RDS configuration. The resulting
+	// BalancerConfig will be used as configuration for a child LB Policy of the
+	// Cluster Manager LB Policy. A nil BalancerConfig is invalid.
+	ParseClusterSpecifierConfig(proto.Message) (BalancerConfig, error)
+}
+
+var (
+	// m is a map from scheme to filter.
+	m = make(map[string]ClusterSpecifier)
+)
+
+// Register registers the ClusterSpecifierPlugin to the ClusterSpecifier map.
+// cs.TypeURLs() will be used as the types for this ClusterSpecifierPlugin.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple cluster specifier
+// plugins are registered with the same type URL, the one registered last will
+// take effect.
+func Register(cs ClusterSpecifier) {
+	for _, u := range cs.TypeURLs() {
+		m[u] = cs
+	}
+}
+
+// Get returns the ClusterSpecifier registered with typeURL.
+//
+// If no cluster specifier is registered with typeURL, nil will be returned.
+func Get(typeURL string) ClusterSpecifier {
+	return m[typeURL]
+}
+
+// UnregisterForTesting unregisters the ClusterSpecifier for testing purposes.
+func UnregisterForTesting(typeURL string) {
+	delete(m, typeURL)
+}