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

internal/ringhash/ringhash.go

@@ -0,0 +1,58 @@
+/*
+ *
+ * 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 (internal) contains functions and types that need to be
+// shared by the ring hash balancer and other gRPC code (such as xDS)
+// without being exported.
+package ringhash
+
+import (
+	"context"
+
+	"google.golang.org/grpc/serviceconfig"
+)
+
+// LBConfig is the balancer config for ring_hash balancer.
+type LBConfig struct {
+	serviceconfig.LoadBalancingConfig `json:"-"`
+
+	MinRingSize       uint64 `json:"minRingSize,omitempty"`
+	MaxRingSize       uint64 `json:"maxRingSize,omitempty"`
+	RequestHashHeader string `json:"requestHashHeader,omitempty"`
+}
+
+// xdsHashKey is the type used as the key to store request hash in the context
+// used when combining the Ring Hash load balancing policy with xDS.
+type xdsHashKey struct{}
+
+// XDSRequestHash returns the request hash in the context and true if it was set
+// from the xDS config selector. If the xDS config selector has not set the hash,
+// it returns 0 and false.
+func XDSRequestHash(ctx context.Context) (uint64, bool) {
+	requestHash := ctx.Value(xdsHashKey{})
+	if requestHash == nil {
+		return 0, false
+	}
+	return requestHash.(uint64), true
+}
+
+// SetXDSRequestHash adds the request hash to the context for use in Ring Hash
+// Load Balancing using xDS route hash_policy.
+func SetXDSRequestHash(ctx context.Context, requestHash uint64) context.Context {
+	return context.WithValue(ctx, xdsHashKey{}, requestHash)
+}