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

orca/orca.go

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2022 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 orca implements Open Request Cost Aggregation, which is an open
+// standard for request cost aggregation and reporting by backends and the
+// corresponding aggregation of such reports by L7 load balancers (such as
+// Envoy) on the data plane. In a proxyless world with gRPC enabled
+// applications, aggregation of such reports will be done by the gRPC client.
+//
+// # Experimental
+//
+// Notice: All APIs is this package are EXPERIMENTAL and may be changed or
+// removed in a later release.
+package orca
+
+import (
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal/balancerload"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/orca/internal"
+)
+
+var logger = grpclog.Component("orca-backend-metrics")
+
+// loadParser implements the Parser interface defined in `internal/balancerload`
+// package. This interface is used by the client stream to parse load reports
+// sent by the server in trailer metadata. The parsed loads are then sent to
+// balancers via balancer.DoneInfo.
+//
+// The grpc package cannot directly call toLoadReport() as that would cause an
+// import cycle. Hence this roundabout method is used.
+type loadParser struct{}
+
+func (loadParser) Parse(md metadata.MD) any {
+	lr, err := internal.ToLoadReport(md)
+	if err != nil {
+		logger.Infof("Parse failed: %v", err)
+	}
+	return lr
+}
+
+func init() {
+	balancerload.SetParser(loadParser{})
+}