Documentation for all the rest of the greeter examples.

examples/cpp/helloworld/greeter_async_client.cc

@@ -42,6 +42,7 @@
 #include <grpc++/completion_queue.h>
 #include <grpc++/create_channel.h>
 #include <grpc++/credentials.h>
+
 #include "helloworld.grpc.pb.h"
 
 using grpc::Channel;

examples/cpp/helloworld/greeter_client.cc

@@ -40,6 +40,7 @@
 #include <grpc++/client_context.h>
 #include <grpc++/create_channel.h>
 #include <grpc++/credentials.h>
+
 #include "helloworld.grpc.pb.h"
 
 using grpc::Channel;
@@ -55,17 +56,28 @@ class GreeterClient {
   GreeterClient(std::shared_ptr<Channel> channel)
       : stub_(Greeter::NewStub(channel)) {}
 
+  // Assambles 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 {
-      return "Rpc failed";
+      return "RPC failed";
     }
   }
 
@@ -74,6 +86,11 @@ class GreeterClient {
 };
 
 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 InsecureCredentials()) and we don't pass any special channel
+  // arguments (that could enable extra channel features, such as compression).
   GreeterClient greeter(
       grpc::CreateChannel("localhost:50051", grpc::InsecureCredentials(),
                           ChannelArguments()));

examples/cpp/helloworld/greeter_server.cc

@@ -40,6 +40,7 @@
 #include <grpc++/server_builder.h>
 #include <grpc++/server_context.h>
 #include <grpc++/server_credentials.h>
+
 #include "helloworld.grpc.pb.h"
 
 using grpc::Server;
@@ -50,6 +51,7 @@ using helloworld::HelloRequest;
 using helloworld::HelloReply;
 using helloworld::Greeter;
 
+// Logic and data behind the server's behavior.
 class GreeterServiceImpl final : public Greeter::Service {
   Status SayHello(ServerContext* context, const HelloRequest* request,
                   HelloReply* reply) override {
@@ -64,10 +66,17 @@ void RunServer() {
   GreeterServiceImpl 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();
 }