wip - orca example

examples/cpp/cmake/common.cmake

@@ -51,6 +51,7 @@ if(GRPC_AS_SUBMODULE)
   # this build.
   set(_PROTOBUF_LIBPROTOBUF libprotobuf)
   set(_REFLECTION grpc++_reflection)
+  set(_ORCA_SERVICE grpcpp_orca_service)
   if(CMAKE_CROSSCOMPILING)
     find_program(_PROTOBUF_PROTOC protoc)
   else()

examples/cpp/orca/BUILD

@@ -0,0 +1,41 @@
+# Copyright 2023 the 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.
+
+licenses(["notice"])
+
+cc_binary(
+    name = "orca_client",
+    srcs = ["orca_client.cc"],
+    defines = ["BAZEL_BUILD"],
+    deps = [
+        "//:grpc++",
+        "//examples/protos:helloworld_cc_grpc",
+        "@com_google_absl//absl/flags:flag",
+        "@com_google_absl//absl/flags:parse",
+    ],
+)
+
+cc_binary(
+    name = "orca_server",
+    srcs = ["orca_server.cc"],
+    defines = ["BAZEL_BUILD"],
+    deps = [
+        "//:grpc++",
+        "//:grpcpp_orca_service",
+        "//examples/protos:helloworld_cc_grpc",
+        "@com_google_absl//absl/flags:flag",
+        "@com_google_absl//absl/flags:parse",
+        "@com_google_absl//absl/strings:str_format",
+    ],
+)

examples/cpp/orca/README.md

@@ -0,0 +1,6 @@
+# gRPC C++ Hello World Example
+
+You can find a complete set of instructions for building gRPC and running the
+Hello World app in the [C++ Quick Start][].
+
+[C++ Quick Start]: https://grpc.io/docs/languages/cpp/quickstart

examples/cpp/orca/orca_client.cc

@@ -0,0 +1,133 @@
+/*
+ *
+ * Copyright 2015 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.
+ *
+ */
+
+#include <cstddef>
+#include <iostream>
+#include <memory>
+#include <string>
+
+#include "absl/flags/flag.h"
+#include "absl/flags/parse.h"
+#include "absl/strings/string_view.h"
+
+#include <grpcpp/grpcpp.h>
+
+#ifdef BAZEL_BUILD
+#include "examples/protos/helloworld.grpc.pb.h"
+
+#include "src/core/lib/config/core_configuration.h"
+#include "src/core/lib/gprpp/ref_counted_ptr.h"
+#include "src/core/lib/load_balancing/lb_policy.h"
+#include "src/core/lib/load_balancing/lb_policy_factory.h"
+#else
+#include "helloworld.grpc.pb.h"
+#endif
+
+ABSL_FLAG(std::string, target, "localhost:50051", "Server address");
+
+namespace {
+
+using grpc::Channel;
+using grpc::ClientContext;
+using grpc::Status;
+
+using grpc_core::LoadBalancingPolicy;
+
+using helloworld::Greeter;
+using helloworld::HelloReply;
+using helloworld::HelloRequest;
+
+constexpr absl::string_view kName = "orca-example";
+class OrcaLBPolicy : public LoadBalancingPolicy {
+ public:
+  absl::string_view name() const override { return kName; }
+};
+
+class OrcaLBPolicyFactory : public grpc_core::LoadBalancingPolicyFactory {
+ public:
+  absl::string_view name() const override { return kName; }
+
+  grpc_core::OrphanablePtr<LoadBalancingPolicy> CreateLoadBalancingPolicy(
+      LoadBalancingPolicy::Args /* args */) const override {
+    return grpc_core::MakeOrphanable<OrcaLBPolicy>();
+  }
+
+  absl::StatusOr<grpc_core::RefCountedPtr<LoadBalancingPolicy::Config>>
+  ParseLoadBalancingConfig(const grpc_core::Json& /* json */) const override {
+    return nullptr;
+  }
+};
+
+class GreeterClient {
+ public:
+  GreeterClient(std::shared_ptr<Channel> channel)
+      : stub_(Greeter::NewStub(channel)) {}
+
+  // Assembles the client's payload, sends it and presents the response back
+  // from the server.
+  std::string SayHello(const std::string& user) {
+    // Data we are sending to the server.
+    HelloRequest request;
+    request.set_name(user);
+
+    // Container for the data we expect from the server.
+    HelloReply reply;
+
+    // Context for the client. It could be used to convey extra information to
+    // the server and/or tweak certain RPC behaviors.
+    ClientContext context;
+
+    // The actual RPC.
+    Status status = stub_->SayHello(&context, request, &reply);
+
+    // Act upon its status.
+    if (status.ok()) {
+      return reply.message();
+    } else {
+      std::cout << status.error_code() << ": " << status.error_message()
+                << std::endl;
+      return "RPC failed";
+    }
+  }
+
+ private:
+  std::unique_ptr<Greeter::Stub> stub_;
+};
+
+}  // namespace
+
+int main(int argc, char** argv) {
+  absl::ParseCommandLine(argc, argv);
+  grpc_core::CoreConfiguration::RegisterBuilder([](auto builder) {
+    builder->lb_policy_registry()->RegisterLoadBalancingPolicyFactory(
+        std::make_unique<OrcaLBPolicyFactory>());
+  });
+  // Instantiate the client. It requires a channel, out of which the actual RPCs
+  // are created. This channel models a connection to an endpoint specified by
+  // the argument "--target=" which is the only expected argument.
+  std::string target_str = absl::GetFlag(FLAGS_target);
+  // We indicate that the channel isn't authenticated (use of
+  // InsecureChannelCredentials()).
+  GreeterClient greeter(
+      grpc::CreateChannel(target_str, grpc::InsecureChannelCredentials()));
+  std::string user("world");
+  std::string reply = greeter.SayHello(user);
+  std::cout << "Greeter received: " << reply << std::endl;
+
+  return 0;
+}

examples/cpp/orca/orca_server.cc

@@ -0,0 +1,101 @@
+/*
+ *
+ * Copyright 2015 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.
+ *
+ */
+
+#include <cstddef>
+#include <iostream>
+#include <memory>
+#include <string>
+
+#include "absl/flags/flag.h"
+#include "absl/flags/parse.h"
+#include "absl/strings/str_format.h"
+
+#include <grpcpp/ext/call_metric_recorder.h>
+#include <grpcpp/ext/orca_service.h>
+#include <grpcpp/grpcpp.h>
+#include <grpcpp/health_check_service_interface.h>
+#include <grpcpp/support/status.h>
+
+#ifdef BAZEL_BUILD
+#include "examples/protos/helloworld.grpc.pb.h"
+#else
+#include "helloworld.grpc.pb.h"
+#endif
+
+using grpc::Server;
+using grpc::ServerBuilder;
+using grpc::ServerContext;
+using grpc::Status;
+using helloworld::Greeter;
+using helloworld::HelloReply;
+using helloworld::HelloRequest;
+
+ABSL_FLAG(uint16_t, port, 50051, "Server port for the service");
+
+// Logic and data behind the server's behavior.
+class GreeterServiceImpl final : public Greeter::Service {
+  Status SayHello(ServerContext* context, const HelloRequest* request,
+                  HelloReply* reply) override {
+    auto recorder = context->ExperimentalGetCallMetricRecorder();
+    if (recorder == nullptr) {
+      return Status(grpc::StatusCode::INTERNAL,
+                    "Unable to access metrics recorder. Make sure "
+                    "EnableCallMetricRecording had been called.");
+    }
+    recorder->RecordRequestCostMetric("db_queries", 10);
+    std::string prefix("Hello ");
+    reply->set_message(prefix + request->name());
+    return Status::OK;
+  }
+};
+
+void RunServer(uint16_t port) {
+  std::string server_address = absl::StrFormat("0.0.0.0:%d", port);
+  GreeterServiceImpl service;
+
+  auto server_metric_recorder =
+      grpc::experimental::ServerMetricRecorder::Create();
+
+  grpc::experimental::OrcaService orca_service(
+      server_metric_recorder.get(),
+      grpc::experimental::OrcaService::Options().set_min_report_duration(
+          absl::Seconds(0.1)));
+
+  grpc::EnableDefaultHealthCheckService(true);
+  ServerBuilder builder;
+  // Listen on the given address without any authentication mechanism.
+  builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
+  // Register "service" as the instance through which we'll communicate with
+  // clients. In this case it corresponds to an *synchronous* service.
+  builder.RegisterService(&service);
+  grpc::ServerBuilder::experimental_type(&builder).EnableCallMetricRecording(
+      nullptr);
+  // Finally assemble the server.
+  std::unique_ptr<Server> server(builder.BuildAndStart());
+  std::cout << "Server listening on " << server_address << std::endl;
+
+  // Wait for the server to shutdown. Note that some other thread must be
+  // responsible for shutting down the server for this call to ever return.
+  server->Wait();
+}
+
+int main(int argc, char** argv) {
+  absl::ParseCommandLine(argc, argv);
+  RunServer(absl::GetFlag(FLAGS_port));
+  return 0;
+}