overhaul of top-level .md files

3 files changed, 491 insertions, 3 deletions

diff --git a/examples/cpp/README.md b/examples/cpp/README.md
index 8e2bb5d13b..0e358bf9a2 100644
--- a/examples/cpp/README.md
+++ b/examples/cpp/README.md
@@ -3,7 +3,7 @@
 ## Installation
 
 To install gRPC on your system, follow the instructions to build from source
-[here](../../INSTALL.md). This also installs the protocol buffer compiler
+[here](../../BUILDING.md). This also installs the protocol buffer compiler
 `protoc` (if you don't have it already), and the C++ gRPC plugin for `protoc`.
 
 ## Hello C++ gRPC!
diff --git a/examples/cpp/cpptutorial.md b/examples/cpp/cpptutorial.md
new file mode 100644
index 0000000000..c40676de13
--- /dev/null
+++ b/examples/cpp/cpptutorial.md
@@ -0,0 +1,488 @@
+# gRPC Basics: C++
+
+This tutorial provides a basic C++ programmer's introduction to working with
+gRPC. By walking through this example you'll learn how to:
+
+- Define a service in a `.proto` file.
+- Generate server and client code using the protocol buffer compiler.
+- Use the C++ gRPC API to write a simple client and server for your service.
+
+It assumes that you are familiar with
+[protocol buffers](https://developers.google.com/protocol-buffers/docs/overview).
+Note that the example in this tutorial uses the proto3 version of the protocol
+buffers language, which is currently in alpha release: you can find out more in
+the [proto3 language guide](https://developers.google.com/protocol-buffers/docs/proto3)
+and see the [release notes](https://github.com/google/protobuf/releases) for the
+new version in the protocol buffers Github repository.
+
+## Why use gRPC?
+
+Our example is a simple route mapping application that lets clients get
+information about features on their route, create a summary of their route, and
+exchange route information such as traffic updates with the server and other
+clients.
+
+With gRPC we can define our service once in a `.proto` file and implement clients
+and servers in any of gRPC's supported languages, which in turn can be run in
+environments ranging from servers inside Google to your own tablet - all the
+complexity of communication between different languages and environments is
+handled for you by gRPC. We also get all the advantages of working with protocol
+buffers, including efficient serialization, a simple IDL, and easy interface
+updating.
+
+## Example code and setup
+
+The example code for our tutorial is in [examples/cpp/route_guide](route_guide).
+You also should have the relevant tools installed to generate the server and
+client interface code - if you don't already, follow the setup instructions in
+[BUILDING.md](../../BUILDING.md).
+
+## Defining the service
+
+Our first step is to define the gRPC *service* and the method *request* and
+*response* types using
+[protocol buffers](https://developers.google.com/protocol-buffers/docs/overview).
+You can see the complete `.proto` file in
+[`examples/protos/route_guide.proto`](../protos/route_guide.proto).
+
+To define a service, you specify a named `service` in your `.proto` file:
+
+```protobuf
+service RouteGuide {
+   ...
+}
+```
+
+Then you define `rpc` methods inside your service definition, specifying their
+request and response types. gRPC lets you define four kinds of service method,
+all of which are used in the `RouteGuide` service:
+
+- A *simple RPC* where the client sends a request to the server using the stub
+  and waits for a response to come back, just like a normal function call.
+
+```protobuf
+   // Obtains the feature at a given position.
+   rpc GetFeature(Point) returns (Feature) {}
+```
+
+- A *server-side streaming RPC* where the client sends a request to the server
+  and gets a stream to read a sequence of messages back. The client reads from
+  the returned stream until there are no more messages. As you can see in our
+  example, you specify a server-side streaming method by placing the `stream`
+  keyword before the *response* type.
+
+```protobuf
+  // Obtains the Features available within the given Rectangle.  Results are
+  // streamed rather than returned at once (e.g. in a response message with a
+  // repeated field), as the rectangle may cover a large area and contain a
+  // huge number of features.
+  rpc ListFeatures(Rectangle) returns (stream Feature) {}
+```
+
+- A *client-side streaming RPC* where the client writes a sequence of messages
+  and sends them to the server, again using a provided stream. Once the client
+  has finished writing the messages, it waits for the server to read them all
+  and return its response. You specify a client-side streaming method by placing
+  the `stream` keyword before the *request* type.
+
+```protobuf
+  // Accepts a stream of Points on a route being traversed, returning a
+  // RouteSummary when traversal is completed.
+  rpc RecordRoute(stream Point) returns (RouteSummary) {}
+```
+
+- A *bidirectional streaming RPC* where both sides send a sequence of messages
+  using a read-write stream. The two streams operate independently, so clients
+  and servers can read and write in whatever order they like: for example, the
+  server could wait to receive all the client messages before writing its
+  responses, or it could alternately read a message then write a message, or
+  some other combination of reads and writes. The order of messages in each
+  stream is preserved. You specify this type of method by placing the `stream`
+  keyword before both the request and the response.
+
+```protobuf
+  // Accepts a stream of RouteNotes sent while a route is being traversed,
+  // while receiving other RouteNotes (e.g. from other users).
+  rpc RouteChat(stream RouteNote) returns (stream RouteNote) {}
+```
+
+Our `.proto` file also contains protocol buffer message type definitions for all
+the request and response types used in our service methods - for example, here's
+the `Point` message type:
+
+```protobuf
+// Points are represented as latitude-longitude pairs in the E7 representation
+// (degrees multiplied by 10**7 and rounded to the nearest integer).
+// Latitudes should be in the range +/- 90 degrees and longitude should be in
+// the range +/- 180 degrees (inclusive).
+message Point {
+  int32 latitude = 1;
+  int32 longitude = 2;
+}
+```
+
+## Generating client and server code
+
+Next we need to generate the gRPC client and server interfaces from our `.proto`
+service definition. We do this using the protocol buffer compiler `protoc` with
+a special gRPC C++ plugin.
+
+For simplicity, we've provided a [Makefile](route_guide/Makefile) that runs
+`protoc` for you with the appropriate plugin, input, and output (if you want to
+run this yourself, make sure you've installed protoc and followed the gRPC code
+[installation instructions](../../BUILDING.md) first):
+
+```shell
+$ make route_guide.grpc.pb.cc route_guide.pb.cc
+```
+
+which actually runs:
+
+```shell
+$ protoc -I ../../protos --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_cpp_plugin` ../../protos/route_guide.proto
+$ protoc -I ../../protos --cpp_out=. ../../protos/route_guide.proto
+```
+
+Running this command generates the following files in your current directory:
+- `route_guide.pb.h`, the header which declares your generated message classes
+- `route_guide.pb.cc`, which contains the implementation of your message classes
+- `route_guide.grpc.pb.h`, the header which declares your generated service
+  classes
+- `route_guide.grpc.pb.cc`, which contains the implementation of your service
+  classes
+
+These contain:
+- All the protocol buffer code to populate, serialize, and retrieve our request
+  and response message types
+- A class called `RouteGuide` that contains
+   - a remote interface type (or *stub*) for clients to call with the methods
+     defined in the `RouteGuide` service.
+   - two abstract interfaces for servers to implement, also with the methods
+     defined in the `RouteGuide` service.
+
+
+<a name="server"></a>
+## Creating the server
+
+First let's look at how we create a `RouteGuide` server. If you're only
+interested in creating gRPC clients, you can skip this section and go straight
+to [Creating the client](#client) (though you might find it interesting
+anyway!).
+
+There are two parts to making our `RouteGuide` service do its job:
+- Implementing the service interface generated from our service definition:
+  doing the actual "work" of our service.
+- Running a gRPC server to listen for requests from clients and return the
+  service responses.
+
+You can find our example `RouteGuide` server in
+[route_guide/route_guide_server.cc](route_guide/route_guide_server.cc). Let's
+take a closer look at how it works.
+
+### Implementing RouteGuide
+
+As you can see, our server has a `RouteGuideImpl` class that implements the
+generated `RouteGuide::Service` interface:
+
+```cpp
+class RouteGuideImpl final : public RouteGuide::Service {
+...
+}
+```
+In this case we're implementing the *synchronous* version of `RouteGuide`, which
+provides our default gRPC server behaviour. It's also possible to implement an
+asynchronous interface, `RouteGuide::AsyncService`, which allows you to further
+customize your server's threading behaviour, though we won't look at this in
+this tutorial.
+
+`RouteGuideImpl` implements all our service methods. Let's look at the simplest
+type first, `GetFeature`, which just gets a `Point` from the client and returns
+the corresponding feature information from its database in a `Feature`.
+
+```cpp
+  Status GetFeature(ServerContext* context, const Point* point,
+                    Feature* feature) override {
+    feature->set_name(GetFeatureName(*point, feature_list_));
+    feature->mutable_location()->CopyFrom(*point);
+    return Status::OK;
+  }
+```
+
+The method is passed a context object for the RPC, the client's `Point` protocol
+buffer request, and a `Feature` protocol buffer to fill in with the response
+information. In the method we populate the `Feature` with the appropriate
+information, and then `return` with an `OK` status to tell gRPC that we've
+finished dealing with the RPC and that the `Feature` can be returned to the
+client.
+
+Now let's look at something a bit more complicated - a streaming RPC.
+`ListFeatures` is a server-side streaming RPC, so we need to send back multiple
+`Feature`s to our client.
+
+```cpp
+Status ListFeatures(ServerContext* context, const Rectangle* rectangle,
+                    ServerWriter<Feature>* writer) override {
+  auto lo = rectangle->lo();
+  auto hi = rectangle->hi();
+  long left = std::min(lo.longitude(), hi.longitude());
+  long right = std::max(lo.longitude(), hi.longitude());
+  long top = std::max(lo.latitude(), hi.latitude());
+  long bottom = std::min(lo.latitude(), hi.latitude());
+  for (const Feature& f : feature_list_) {
+    if (f.location().longitude() >= left &&
+        f.location().longitude() <= right &&
+        f.location().latitude() >= bottom &&
+        f.location().latitude() <= top) {
+      writer->Write(f);
+    }
+  }
+  return Status::OK;
+}
+```
+
+As you can see, instead of getting simple request and response objects in our
+method parameters, this time we get a request object (the `Rectangle` in which
+our client wants to find `Feature`s) and a special `ServerWriter` object. In the
+method, we populate as many `Feature` objects as we need to return, writing them
+to the `ServerWriter` using its `Write()` method. Finally, as in our simple RPC,
+we `return Status::OK` to tell gRPC that we've finished writing responses.
+
+If you look at the client-side streaming method `RecordRoute` you'll see it's
+quite similar, except this time we get a `ServerReader` instead of a request
+object and a single response. We use the `ServerReader`s `Read()` method to
+repeatedly read in our client's requests to a request object (in this case a
+`Point`) until there are no more messages: the server needs to check the return
+value of `Read()` after each call. If `true`, the stream is still good and it
+can continue reading; if `false` the message stream has ended.
+
+```cpp
+while (stream->Read(&point)) {
+  ...//process client input
+}
+```
+Finally, let's look at our bidirectional streaming RPC `RouteChat()`.
+
+```cpp
+  Status RouteChat(ServerContext* context,
+                   ServerReaderWriter<RouteNote, RouteNote>* stream) override {
+    std::vector<RouteNote> received_notes;
+    RouteNote note;
+    while (stream->Read(&note)) {
+      for (const RouteNote& n : received_notes) {
+        if (n.location().latitude() == note.location().latitude() &&
+            n.location().longitude() == note.location().longitude()) {
+          stream->Write(n);
+        }
+      }
+      received_notes.push_back(note);
+    }
+
+    return Status::OK;
+  }
+```
+
+This time we get a `ServerReaderWriter` that can be used to read *and* write
+messages. The syntax for reading and writing here is exactly the same as for our
+client-streaming and server-streaming methods. Although each side will always
+get the other's messages in the order they were written, both the client and
+server can read and write in any order — the streams operate completely
+independently.
+
+### Starting the server
+
+Once we've implemented all our methods, we also need to start up a gRPC server
+so that clients can actually use our service. The following snippet shows how we
+do this for our `RouteGuide` service:
+
+```cpp
+void RunServer(const std::string& db_path) {
+  std::string server_address("0.0.0.0:50051");
+  RouteGuideImpl service(db_path);
+
+  ServerBuilder builder;
+  builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
+  builder.RegisterService(&service);
+  std::unique_ptr<Server> server(builder.BuildAndStart());
+  std::cout << "Server listening on " << server_address << std::endl;
+  server->Wait();
+}
+```
+As you can see, we build and start our server using a `ServerBuilder`. To do this, we:
+
+1. Create an instance of our service implementation class `RouteGuideImpl`.
+1. Create an instance of the factory `ServerBuilder` class.
+1. Specify the address and port we want to use to listen for client requests
+   using the builder's `AddListeningPort()` method.
+1. Register our service implementation with the builder.
+1. Call `BuildAndStart()` on the builder to create and start an RPC server for
+   our service.
+1. Call `Wait()` on the server to do a blocking wait until process is killed or
+   `Shutdown()` is called.
+
+<a name="client"></a>
+## Creating the client
+
+In this section, we'll look at creating a C++ client for our `RouteGuide`
+service. You can see our complete example client code in
+[route_guide/route_guide_client.cc](route_guide/route_guide_client.cc).
+
+### Creating a stub
+
+To call service methods, we first need to create a *stub*.
+
+First we need to create a gRPC *channel* for our stub, specifying the server
+address and port we want to connect to without SSL:
+
+```cpp
+grpc::CreateChannel("localhost:50051", grpc::InsecureChannelCredentials());
+```
+
+Now we can use the channel to create our stub using the `NewStub` method
+provided in the `RouteGuide` class we generated from our `.proto`.
+
+```cpp
+public:
+ RouteGuideClient(std::shared_ptr<Channel> channel, const std::string& db)
+     : stub_(RouteGuide::NewStub(channel)) {
+   ...
+ }
+```
+
+### Calling service methods
+
+Now let's look at how we call our service methods. Note that in this tutorial
+we're calling the *blocking/synchronous* versions of each method: this means
+that the RPC call waits for the server to respond, and will either return a
+response or raise an exception.
+
+#### Simple RPC
+
+Calling the simple RPC `GetFeature` is nearly as straightforward as calling a
+local method.
+
+```cpp
+  Point point;
+  Feature feature;
+  point = MakePoint(409146138, -746188906);
+  GetOneFeature(point, &feature);
+
+...
+
+  bool GetOneFeature(const Point& point, Feature* feature) {
+    ClientContext context;
+    Status status = stub_->GetFeature(&context, point, feature);
+    ...
+  }
+```
+
+As you can see, we create and populate a request protocol buffer object (in our
+case `Point`), and create a response protocol buffer object for the server to
+fill in. We also create a `ClientContext` object for our call - you can
+optionally set RPC configuration values on this object, such as deadlines,
+though for now we'll use the default settings. Note that you cannot reuse this
+object between calls. Finally, we call the method on the stub, passing it the
+context, request, and response. If the method returns `OK`, then we can read the
+response information from the server from our response object.
+
+```cpp
+std::cout << "Found feature called " << feature->name()  << " at "
+          << feature->location().latitude()/kCoordFactor_ << ", "
+          << feature->location().longitude()/kCoordFactor_ << std::endl;
+```
+
+#### Streaming RPCs
+
+Now let's look at our streaming methods. If you've already read [Creating the
+server](#server) some of this may look very familiar - streaming RPCs are
+implemented in a similar way on both sides. Here's where we call the server-side
+streaming method `ListFeatures`, which returns a stream of geographical
+`Feature`s:
+
+```cpp
+std::unique_ptr<ClientReader<Feature> > reader(
+    stub_->ListFeatures(&context, rect));
+while (reader->Read(&feature)) {
+  std::cout << "Found feature called "
+            << feature.name() << " at "
+            << feature.location().latitude()/kCoordFactor_ << ", "
+            << feature.location().longitude()/kCoordFactor_ << std::endl;
+}
+Status status = reader->Finish();
+```
+
+Instead of passing the method a context, request, and response, we pass it a
+context and request and get a `ClientReader` object back. The client can use the
+`ClientReader` to read the server's responses. We use the `ClientReader`s
+`Read()` method to repeatedly read in the server's responses to a response
+protocol buffer object (in this case a `Feature`) until there are no more
+messages: the client needs to check the return value of `Read()` after each
+call. If `true`, the stream is still good and it can continue reading; if
+`false` the message stream has ended. Finally, we call `Finish()` on the stream
+to complete the call and get our RPC status.
+
+The client-side streaming method `RecordRoute` is similar, except there we pass
+the method a context and response object and get back a `ClientWriter`.
+
+```cpp
+    std::unique_ptr<ClientWriter<Point> > writer(
+        stub_->RecordRoute(&context, &stats));
+    for (int i = 0; i < kPoints; i++) {
+      const Feature& f = feature_list_[feature_distribution(generator)];
+      std::cout << "Visiting point "
+                << f.location().latitude()/kCoordFactor_ << ", "
+                << f.location().longitude()/kCoordFactor_ << std::endl;
+      if (!writer->Write(f.location())) {
+        // Broken stream.
+        break;
+      }
+      std::this_thread::sleep_for(std::chrono::milliseconds(
+          delay_distribution(generator)));
+    }
+    writer->WritesDone();
+    Status status = writer->Finish();
+    if (status.IsOk()) {
+      std::cout << "Finished trip with " << stats.point_count() << " points\n"
+                << "Passed " << stats.feature_count() << " features\n"
+                << "Travelled " << stats.distance() << " meters\n"
+                << "It took " << stats.elapsed_time() << " seconds"
+                << std::endl;
+    } else {
+      std::cout << "RecordRoute rpc failed." << std::endl;
+    }
+```
+
+Once we've finished writing our client's requests to the stream using `Write()`,
+we need to call `WritesDone()` on the stream to let gRPC know that we've
+finished writing, then `Finish()` to complete the call and get our RPC status.
+If the status is `OK`, our response object that we initially passed to
+`RecordRoute()` will be populated with the server's response.
+
+Finally, let's look at our bidirectional streaming RPC `RouteChat()`. In this
+case, we just pass a context to the method and get back a `ClientReaderWriter`,
+which we can use to both write and read messages.
+
+```cpp
+std::shared_ptr<ClientReaderWriter<RouteNote, RouteNote> > stream(
+    stub_->RouteChat(&context));
+```
+
+The syntax for reading and writing here is exactly the same as for our
+client-streaming and server-streaming methods. Although each side will always
+get the other's messages in the order they were written, both the client and
+server can read and write in any order — the streams operate completely
+independently.
+
+## Try it out!
+
+Build client and server:
+```shell
+$ make
+```
+Run the server, which will listen on port 50051:
+```shell
+$ ./route_guide_server
+```
+Run the client (in a different terminal):
+```shell
+$ ./route_guide_client
+```
diff --git a/examples/cpp/helloworld/README.md b/examples/cpp/helloworld/README.md
index 18d3d79dcc..c598658b1d 100644
--- a/examples/cpp/helloworld/README.md
+++ b/examples/cpp/helloworld/README.md
@@ -1,8 +1,8 @@
 # gRPC C++ Hello World Tutorial
 
 ### Install gRPC
-Make sure you have installed gRPC on your system. Follow the instructions here:
-[https://github.com/grpc/grpc/blob/master/INSTALL](../../../INSTALL.md).
+Make sure you have installed gRPC on your system. Follow the
+[BUILDING.md](../../../BUILDING.md) instructions.
 
 ### Get the tutorial source code