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

resolver/ringhash/attr.go

@@ -0,0 +1,60 @@
+/*
+ *
+ * Copyright 2025 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 ringhash implements resolver related functions for the ring_hash
+// load balancing policy.
+package ringhash
+
+import (
+	"google.golang.org/grpc/resolver"
+)
+
+type hashKeyType string
+
+// hashKeyKey is the key to store the ring hash key attribute in
+// a resolver.Endpoint attribute.
+const hashKeyKey = hashKeyType("grpc.resolver.ringhash.hash_key")
+
+// SetHashKey sets the hash key for this endpoint. Combined with the ring_hash
+// load balancing policy, it allows placing the endpoint on the ring based on an
+// arbitrary string instead of the IP address. If hashKey is empty, the endpoint
+// is returned unmodified.
+//
+// # Experimental
+//
+// Notice: This API is EXPERIMENTAL and may be changed or removed in a
+// later release.
+func SetHashKey(endpoint resolver.Endpoint, hashKey string) resolver.Endpoint {
+	if hashKey == "" {
+		return endpoint
+	}
+	endpoint.Attributes = endpoint.Attributes.WithValue(hashKeyKey, hashKey)
+	return endpoint
+}
+
+// HashKey returns the hash key attribute of endpoint. If this attribute is
+// not set, it returns the empty string.
+//
+// # Experimental
+//
+// Notice: This API is EXPERIMENTAL and may be changed or removed in a
+// later release.
+func HashKey(endpoint resolver.Endpoint) string {
+	hashKey, _ := endpoint.Attributes.Value(hashKeyKey).(string)
+	return hashKey
+}