Merge pull request #17687 from yashykt/interceptionexamples

Naive client server implementation for key value service example

examples/BUILD

@@ -98,3 +98,17 @@ cc_binary(
     defines = ["BAZEL_BUILD"],
     deps = [":helloworld", "//:grpc++"],
 )
+
+cc_binary(
+    name = "keyvaluestore_client",
+    srcs = ["cpp/keyvaluestore/client.cc"],
+    defines = ["BAZEL_BUILD"],
+    deps = [":keyvaluestore", "//:grpc++"],
+)
+
+cc_binary(
+    name = "keyvaluestore_server",
+    srcs = ["cpp/keyvaluestore/server.cc"],
+    defines = ["BAZEL_BUILD"],
+    deps = [":keyvaluestore", "//:grpc++"],
+)

examples/cpp/keyvaluestore/client.cc

@@ -0,0 +1,86 @@
+/*
+ *
+ * Copyright 2018 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 <vector>
+
+#include <grpcpp/grpcpp.h>
+
+#ifdef BAZEL_BUILD
+#include "examples/protos/keyvaluestore.grpc.pb.h"
+#else
+#include "keyvaluestore.grpc.pb.h"
+#endif
+
+using grpc::Channel;
+using grpc::ClientContext;
+using grpc::Status;
+using keyvaluestore::KeyValueStore;
+using keyvaluestore::Request;
+using keyvaluestore::Response;
+
+class KeyValueStoreClient {
+ public:
+  KeyValueStoreClient(std::shared_ptr<Channel> channel)
+      : stub_(KeyValueStore::NewStub(channel)) {}
+
+  // Requests each key in the vector and displays the key and its corresponding
+  // value as a pair
+  void GetValues(const std::vector<std::string>& keys) {
+    // Context for the client. It could be used to convey extra information to
+    // the server and/or tweak certain RPC behaviors.
+    ClientContext context;
+    auto stream = stub_->GetValues(&context);
+    for (const auto& key : keys) {
+      // Key we are sending to the server.
+      Request request;
+      request.set_key(key);
+      stream->Write(request);
+
+      // Get the value for the sent key
+      Response response;
+      stream->Read(&response);
+      std::cout << key << " : " << response.value() << "\n";
+    }
+    stream->WritesDone();
+    Status status = stream->Finish();
+    if (!status.ok()) {
+      std::cout << status.error_code() << ": " << status.error_message()
+                << std::endl;
+      std::cout << "RPC failed";
+    }
+  }
+
+ private:
+  std::unique_ptr<KeyValueStore::Stub> stub_;
+};
+
+int main(int argc, char** argv) {
+  // Instantiate the client. It requires a channel, out of which the actual RPCs
+  // are created. This channel models a connection to an endpoint (in this case,
+  // localhost at port 50051). We indicate that the channel isn't authenticated
+  // (use of InsecureChannelCredentials()).
+  KeyValueStoreClient client(grpc::CreateChannel(
+      "localhost:50051", grpc::InsecureChannelCredentials()));
+  std::vector<std::string> keys = {"key1", "key2", "key3", "key4", "key5"};
+  client.GetValues(keys);
+
+  return 0;
+}

examples/cpp/keyvaluestore/server.cc

@@ -0,0 +1,97 @@
+/*
+ *
+ * Copyright 2018 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 <vector>
+
+#include <grpcpp/grpcpp.h>
+
+#ifdef BAZEL_BUILD
+#include "examples/protos/keyvaluestore.grpc.pb.h"
+#else
+#include "keyvaluestore.grpc.pb.h"
+#endif
+
+using grpc::Server;
+using grpc::ServerBuilder;
+using grpc::ServerContext;
+using grpc::ServerReaderWriter;
+using grpc::Status;
+using keyvaluestore::KeyValueStore;
+using keyvaluestore::Request;
+using keyvaluestore::Response;
+
+struct kv_pair {
+  const char* key;
+  const char* value;
+};
+
+static const kv_pair kvs_map[] = {
+    {"key1", "value1"}, {"key2", "value2"}, {"key3", "value3"},
+    {"key4", "value4"}, {"key5", "value5"},
+};
+
+const char* get_value_from_map(const char* key) {
+  for (size_t i = 0; i < sizeof(kvs_map) / sizeof(kv_pair); ++i) {
+    if (strcmp(key, kvs_map[i].key) == 0) {
+      return kvs_map[i].value;
+    }
+  }
+  return "";
+}
+
+// Logic and data behind the server's behavior.
+class KeyValueStoreServiceImpl final : public KeyValueStore::Service {
+  Status GetValues(ServerContext* context,
+                   ServerReaderWriter<Response, Request>* stream) override {
+    Request request;
+    while (stream->Read(&request)) {
+      Response response;
+      response.set_value(get_value_from_map(request.key().c_str()));
+      stream->Write(response);
+    }
+    return Status::OK;
+  }
+};
+
+void RunServer() {
+  std::string server_address("0.0.0.0:50051");
+  KeyValueStoreServiceImpl service;
+
+  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);
+  // 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) {
+  RunServer();
+
+  return 0;
+}