[examples] Clean-up xds example (#33166)

2 years ago · 6e1f46fda7
parent 0526a51734
commit 6e1f46fda7
4 changed files with 300 additions and 0 deletions
--- a/examples/cpp/xds/BUILD
+++ b/examples/cpp/xds/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 = "xds_greeter_client",
+    srcs = ["xds_greeter_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 = "xds_greeter_server",
+    srcs = ["xds_greeter_server.cc"],
+    defines = ["BAZEL_BUILD"],
+    deps = [
+        "//:grpc++",
+        "//:grpc++_reflection",
+        "//:grpcpp_admin",
+        "//examples/protos:helloworld_cc_grpc",
+        "@com_google_absl//absl/flags:flag",
+        "@com_google_absl//absl/flags:parse",
+    ],
+)
--- a/examples/cpp/xds/README.md
+++ b/examples/cpp/xds/README.md
@ -0,0 +1,37 @@
+# gRPC C++ xDS Hello World Example
+
+This xDS example builds on the [Hello World Example](https://github.com/grpc/grpc/tree/master/examples/cpp/helloworld) and changes the gRPC client and server to accept configuration from an xDS control plane.
+
+## Configuration
+
+The client takes two command-line arguments -
+* target - By default, the client tries to connect to the xDS "xds:///helloworld:50051" and gRPC would use xDS to resolve this target and connect to the server backend. This can be overriden to change the target.
+* secure - Bool value, defaults to true. When this is set, [XdsCredentials](https://github.com/grpc/proposal/blob/master/A29-xds-tls-security.md) will be used with a fallback on `InsecureChannelCredentials`. If unset, `InsecureChannelCredentials` will be used.
+
+The server takes three command-line arguments -
+* port - Port on which the Hello World service is run. Defaults to 50051.
+* mantenance_port - If secure mode is used (see below), the [Admin](https://github.com/grpc/proposal/blob/master/A38-admin-interface-api.md) service is exposed on this port. If secure mode is not used, `maintenance_port` is unused, and the Admin service is just exposed on `port`. Defaults to 50052.
+* secure - Bool value, defaults to true. When this is set, [XdsServerCredentials](https://github.com/grpc/proposal/blob/master/A29-xds-tls-security.md) will be used with a fallback on `InsecureServerCredentials`. If unset, `InsecureServerCredentials` will be used.
+
+## Running the example
+
+Currently, this example and some of the gRPC xDS libraries that it depends on only builds with bazel. CMake support will be introduced in the future.
+
+To use XDS, you should first deploy the XDS management server in your deployment environment and know its name. You need to set the `GRPC_XDS_BOOTSTRAP` environment variable to point to the gRPC XDS bootstrap file (see [gRFC A27](https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md#xdsclient-and-bootstrap-file) for the bootstrap format). This is needed by both client and server.
+
+Please view [GCP instructions](https://cloud.google.com/traffic-director/docs/security-proxyless-setup) as an example.
+
+To run the server -
+
+```
+$ export GRPC_XDS_BOOTSTRAP=/path/to/bootstrap.json
+$ tools/bazel run examples/cpp/xds:greeter_server
+```
+
+To run the client -
+
+```
+$ export GRPC_XDS_BOOTSTRAP=/path/to/bootstrap.json
+$ tools/bazel run examples/cpp/xds:greeter_client
+```
+
--- a/examples/cpp/xds/xds_greeter_client.cc
+++ b/examples/cpp/xds/xds_greeter_client.cc
@ -0,0 +1,109 @@
+/*
+ *
+ * Copyright 2023 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 <condition_variable>
+#include <iostream>
+#include <memory>
+#include <mutex>
+#include <string>
+
+#include "absl/flags/flag.h"
+#include "absl/flags/parse.h"
+
+#include <grpcpp/grpcpp.h>
+
+#ifdef BAZEL_BUILD
+#include "examples/protos/helloworld.grpc.pb.h"
+#else
+#include "helloworld.grpc.pb.h"
+#endif
+
+ABSL_FLAG(std::string, target, "xds:///helloworld:50051", "Target string");
+ABSL_FLAG(bool, secure, true, "Secure mode");
+
+using grpc::Channel;
+using grpc::ClientContext;
+using grpc::Status;
+using helloworld::Greeter;
+using helloworld::HelloReply;
+using helloworld::HelloRequest;
+
+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.
+    std::mutex mu;
+    std::condition_variable cv;
+    bool done = false;
+    Status status;
+    stub_->async()->SayHello(&context, &request, &reply,
+                             [&mu, &cv, &done, &status](Status s) {
+                               status = std::move(s);
+                               std::lock_guard<std::mutex> lock(mu);
+                               done = true;
+                               cv.notify_one();
+                             });
+
+    std::unique_lock<std::mutex> lock(mu);
+    while (!done) {
+      cv.wait(lock);
+    }
+
+    // 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_;
+};
+
+int main(int argc, char** argv) {
+  absl::ParseCommandLine(argc, argv);
+  GreeterClient greeter(grpc::CreateChannel(
+      absl::GetFlag(FLAGS_target),
+      absl::GetFlag(FLAGS_secure)
+          ? grpc::XdsCredentials(grpc::InsecureChannelCredentials())
+          : grpc::InsecureChannelCredentials()));
+  std::string user("world");
+  std::string reply = greeter.SayHello(user);
+  std::cout << "Greeter received: " << reply << std::endl;
+
+  return 0;
+}
--- a/examples/cpp/xds/xds_greeter_server.cc
+++ b/examples/cpp/xds/xds_greeter_server.cc
@ -0,0 +1,113 @@
+/*
+ *
+ * Copyright 2023 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 <iostream>
+#include <memory>
+#include <string>
+
+#include "absl/flags/flag.h"
+#include "absl/flags/parse.h"
+#include "absl/strings/str_cat.h"
+
+#include <grpcpp/ext/admin_services.h>
+#include <grpcpp/ext/proto_server_reflection_plugin.h>
+#include <grpcpp/grpcpp.h>
+#include <grpcpp/health_check_service_interface.h>
+#include <grpcpp/xds_server_builder.h>
+
+#ifdef BAZEL_BUILD
+#include "examples/protos/helloworld.grpc.pb.h"
+#else
+#include "helloworld.grpc.pb.h"
+#endif
+
+ABSL_FLAG(int32_t, port, 50051, "Server port for service.");
+ABSL_FLAG(int32_t, maintenance_port, 50052,
+          "Server port for maintenance if --secure is used.");
+ABSL_FLAG(bool, secure, true, "Secure mode");
+
+using grpc::CallbackServerContext;
+using grpc::Server;
+using grpc::ServerBuilder;
+using grpc::ServerUnaryReactor;
+using grpc::Status;
+using helloworld::Greeter;
+using helloworld::HelloReply;
+using helloworld::HelloRequest;
+
+// Logic and data behind the server's behavior.
+class GreeterServiceImpl final : public Greeter::CallbackService {
+  ServerUnaryReactor* SayHello(CallbackServerContext* context,
+                               const HelloRequest* request,
+                               HelloReply* reply) override {
+    std::string prefix("Hello ");
+    reply->set_message(prefix + request->name());
+
+    ServerUnaryReactor* reactor = context->DefaultReactor();
+    reactor->Finish(Status::OK);
+    return reactor;
+  }
+};
+
+void RunServer() {
+  grpc::EnableDefaultHealthCheckService(true);
+  grpc::reflection::InitProtoReflectionServerBuilderPlugin();
+  int port = absl::GetFlag(FLAGS_port);
+  int maintenance_port = absl::GetFlag(FLAGS_maintenance_port);
+  grpc::XdsServerBuilder xds_builder;
+  ServerBuilder builder;
+  std::unique_ptr<Server> xds_enabled_server;
+  std::unique_ptr<Server> server;
+  GreeterServiceImpl service;
+  // Register "service" as the instance through which we'll communicate with
+  // clients. In this case it corresponds to an *synchronous* service.
+  xds_builder.RegisterService(&service);
+  if (absl::GetFlag(FLAGS_secure)) {
+    // Listen on the given address with XdsServerCredentials and a fallback of
+    // InsecureServerCredentials
+    xds_builder.AddListeningPort(
+        absl::StrCat("0.0.0.0:", port),
+        grpc::XdsServerCredentials(grpc::InsecureServerCredentials()));
+    xds_enabled_server = xds_builder.BuildAndStart();
+    gpr_log(GPR_INFO, "Server starting on 0.0.0.0:%d", port);
+    grpc::AddAdminServices(&builder);
+    // For the maintenance server, do not use any authentication mechanism.
+    builder.AddListeningPort(absl::StrCat("0.0.0.0:", maintenance_port),
+                             grpc::InsecureServerCredentials());
+    server = builder.BuildAndStart();
+    gpr_log(GPR_INFO, "Maintenance server listening on 0.0.0.0:%d",
+            maintenance_port);
+  } else {
+    grpc::AddAdminServices(&xds_builder);
+    // Listen on the given address without any authentication mechanism.
+    builder.AddListeningPort(absl::StrCat("0.0.0.0:", port),
+                             grpc::InsecureServerCredentials());
+    server = xds_builder.BuildAndStart();
+    gpr_log(GPR_INFO, "Server listening on 0.0.0.0:%d", port);
+  }
+
+  // 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();
+  return 0;
+}