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Merge branch 'master' of https://github.com/grpc/grpc-common

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Xiao Hang 10 years ago
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  1. 2
      README.md
  2. 6
      go/README.md
  3. 404
      go/gotutorial.md
  4. 4
      go/helloworld/helloworld.pb.go
  5. 363
      java/javatutorial.md
  6. 20
      node/README.md
  7. 362
      node/route_guide/README.md
  8. 3
      protos/route_guide.proto
  9. 1
      python/helloworld/.gitignore
  10. 111
      python/helloworld/README.md
  11. 44
      python/helloworld/greeter_client.py
  12. 56
      python/helloworld/greeter_server.py
  13. 49
      python/helloworld/helloworld.proto
  14. 158
      python/helloworld/helloworld_pb2.py
  15. 8
      python/helloworld/run_client.sh
  16. 4
      python/helloworld/run_codegen.sh
  17. 9
      python/helloworld/run_server.sh
  18. 2
      ruby/Gemfile
  19. 4
      ruby/README.md

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README.md
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@ -16,7 +16,7 @@ You can find quick start guides for each language, including installation instru
* [ruby](https://github.com/grpc/grpc-common/tree/master/ruby)
* [Node.js](https://github.com/grpc/grpc-common/tree/master/node)
* [Android Java](https://github.com/grpc/grpc-common/tree/master/java/android)
* Python is coming soon
* [Python](https://github.com/grpc/grpc-common/tree/master/python/helloworld)
## What's in this repository?

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go/README.md
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@ -1,6 +1,10 @@
gRPC in 3 minutes (Go)
======================
BACKGROUND
-------------
For this sample, we've already generated the server and client stubs from [helloworld.proto](https://github.com/grpc/grpc-common/blob/master/protos/helloworld.proto).
PREREQUISITES
-------------
@ -45,5 +49,5 @@ OPTIONAL - Rebuilding the generated code
$ go get -a github.com/golang/protobuf/protoc-gen-go
$
$ # from this dir; invoke protoc
$ protoc -I ../protos ../protos/helloworld.proto --go_out=plugins=grpc:.
$ protoc -I ../protos ../protos/helloworld.proto --go_out=plugins=grpc:helloworld
```

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go/gotutorial.md
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@ -0,0 +1,404 @@
#gRPC Basics: Go
This tutorial provides a basic Go 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 Go gRPC API to write a simple client and server for your service.
It assumes that you have read the [Getting started](https://github.com/grpc/grpc-common) guide and 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 see the [release notes](https://github.com/google/protobuf/releases) for the new version in the protocol buffers Github repository.
This isn't a comprehensive guide to using gRPC in Go: more reference documentation is coming soon.
## 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 [grpc/grpc-go/examples/route_guide](https://github.com/grpc/grpc-go/tree/master/examples/route_guide). To download the example, clone the `grpc-go` repository by running the following command:
```shell
$ go get google.golang.org/grpc
```
Then change your current directory to `grpc-go/examples/route_guide`:
```shell
$ cd $GOPATH/src/google.golang.org/grpc/examples/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 [the Go quick start guide](https://github.com/grpc/grpc-common/tree/master/go).
## Defining the service
Our first step (as you'll know from [Getting started](https://github.com/grpc/grpc-common)) 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 [`grpc-common/protos/route_guide.proto`](https://github.com/grpc/grpc-common/blob/master/protos/route_guide.proto).
To define a service, you specify a named `service` in your .proto file:
```
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.
```
// 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.
```
// 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 server-side streaming method by placing the `stream` keyword before the *request* type.
```
// 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.
```
// 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:
```
// 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 Go plugin.
For simplicity, we've provided a [bash script](https://github.com/grpc/grpc-go/blob/master/codegen.sh) 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](https://github.com/grpc/grpc/blob/master/INSTALL) first):
```shell
$ codegen.sh route_guide.proto
```
which actually runs:
```shell
$ protoc --go_out=plugins=grpc:. route_guide.proto
```
Running this command generates the following files in your current directory:
- `route_guide.pb.go`
This contains:
- All the protocol buffer code to populate, serialize, and retrieve our request and response message types
- An interface type (or *stub*) for clients to call with the methods defined in the `RouteGuide` service.
- An interface type 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 [grpc-go/examples/route_guide/server/server.go](https://github.com/grpc/grpc-go/tree/master/examples/route_guide/server/server.go). Let's take a closer look at how it works.
### Implementing RouteGuide
As you can see, our server has a `routeGuideServer` struct type that implements the generated `RouteGuideServer` interface:
```go
type routeGuideServer struct {
...
}
...
func (s *routeGuideServer) GetFeature(ctx context.Context, point *pb.Point) (*pb.Feature, error) {
...
}
...
func (s *routeGuideServer) ListFeatures(rect *pb.Rectangle, stream pb.RouteGuide_ListFeaturesServer) error {
...
}
...
func (s *routeGuideServer) RecordRoute(stream pb.RouteGuide_RecordRouteServer) error {
...
}
...
func (s *routeGuideServer) RouteChat(stream pb.RouteGuide_RouteChatServer) error {
...
}
...
```
`routeGuideServer` 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`.
```go
func (s *routeGuideServer) GetFeature(ctx context.Context, point *pb.Point) (*pb.Feature, error) {
for _, feature := range s.savedFeatures {
if proto.Equal(feature.Location, point) {
return feature, nil
}
}
// No feature was found, return an unnamed feature
return &pb.Feature{"", point}, nil
}
```
The method is passed a context object for the RPC, the client's `Point` protocol buffer request. It returns a `Feature` protocol buffer object with the response information and an error. In the method we populate the `Feature` with the appropriate information, and then `return` it along with an `nil` error 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.
```go
func (s *routeGuideServer) ListFeatures(rect *pb.Rectangle, stream pb.RouteGuide_ListFeaturesServer) error {
for _, feature := range s.savedFeatures {
if inRange(feature.Location, rect) {
if err := stream.Send(feature); err != nil {
return err
}
}
}
return nil
}
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 `RouteGuide_ListFeaturesServer` object. In the method, we populate as many `Feature` objects as we need to return, writing them to the `RouteGuide_ListFeaturesServer` using its `Send()` method. Finally, as in our simple RPC, we return a `nil` error to tell gRPC that we've finished writing responses. Should there be any error happened in this call, we return a non-`nil` error and the gRPC layer will translate it into an appropriate RPC status to be sent on the wire.
If you look at the client-side streaming method `RecordRoute` you'll see it's quite similar, except this time we don't have to pass the method a request. Instead, we pass in a `RouteGuide_RecordRouteServer`, through which we can receive client messages using its `Recv()` method.
We use the `RouteGuide_RecordRouteServer`s `Recv()` 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 the error returned from `Read()` after each call. If `nil`, the stream is still good and it can continue reading; if it's `io.EOF` the message stream has ended. Otherwise, we return the error as is so that it'll be translated to an RPC status by the gRPC layer.
```go
for {
point, err := stream.Recv()
if err == io.EOF {
return stream.SendAndClose(&pb.RouteSummary{
...
})
}
if err != nil {
return err
}
...
}
```
Finally, let's look at our bidirectional streaming RPC `RouteChat()`.
```go
func (s *routeGuideServer) RouteChat(stream pb.RouteGuide_RouteChatServer) error {
for {
in, err := stream.Recv()
if err == io.EOF {
return nil
}
if err != nil {
return err
}
key := serialize(in.Location)
... // look for notes to be sent to client
for _, note := range s.routeNotes[key] {
if err := stream.Send(note); err != nil {
return err
}
}
}
}
```
This time we get a `RouteGuide_RouteChatServer` 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:
```go
flag.Parse()
lis, err := net.Listen("tcp", fmt.Sprintf(":%d", *port))
if err != nil {
log.Fatalf("failed to listen: %v", err)
}
grpcServer := grpc.NewServer()
pb.RegisterRouteGuideServer(grpcServer, newServer())
... // determine whether to use TLS
grpcServer.Serve(lis)
```
As you can see, we build our server using `grpc.NewServer()`. To do this, we:
1. Specify the port we want to use to listen for client requests using `lis, err := net.Listen("tcp", fmt.Sprintf(":%d", *port))`.
2. Create an instance of the gRPC server, by `grpc.NewServer()`.
3. Create an instance of our service implementation class `routeGuideServer`, by
calling the constructor `newServer()`, which essentially does `s := new(routeGuideServer)`.
4. Register our service implementation with the gRPC server.
5. Call `Serve()` on the server to do a blocking wait until process is killed or `Stop()` is called.
<a name="client"></a>
## Creating the client
In this section, we'll look at creating a Go client for our `RouteGuide` service. You can see our complete example client code in [grpc-go/examples/route_guide/client/client.go](https://github.com/grpc/grpc-go/tree/master/examples/route_guide/server/client.go).
### Creating a stub
To call service methods, we first need to create a gRPC "channel* as the message communication media by simply passing the server address and port number as follows:
```go
conn, err := grpc.Dial(*serverAddr)
defer conn.Close()
```
We can use DialOptions to set the auth credentials (e.g., TLS, GCE crednetials, JWT credentials) in grpc.Dial if the service you request requires that.
Once the gRPC *channel* is setup, we need a client *stub* to perform RPCs by using the `NewRouteGuideClient` method provided in the `pb` package we generated from our .proto.
```go
client := pb.NewRouteGuideClient(conn)
```
### Calling service methods
Now let's look at how we call our service methods. Note that in gRPC-Go, RPC operates in a blocking/synchronous mode, which means that the RPC call waits for the server to respond, and will either return a response or an error.
#### Simple RPC
Calling the simple RPC `GetFeature` is nearly as straightforward as calling a local method.
```go
printFeature(client, &pb.Point{409146138, -746188906})
...
func printFeature(client pb.RouteGuideClient, point *pb.Point) {
log.Printf("Getting feature for point (%d, %d)", point.Latitude, point.Longitude)
feature, err := client.GetFeature(context.Background(), point)
if err != nil {
log.Fatalf("%v.GetFeatures(_) = _, %v: ", client, err)
return
}
log.Println(feature)
}
```
As you can see, we create and populate a request protocol buffer object (in our case `Point`). We also pass a `context.Context` object which allows us to time-out/cancel an RPC in flight. Finally, we call the method on the stub, passing it the context, and request. If the call doesn't return an error, then we can read the response information from the server from the first return value.
```go
log.Println(feature)
```
#### 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:
```go
func printFeatures(client pb.RouteGuideClient, rect *pb.Rectangle) {
stream, err := client.ListFeatures(context.Background(), rect)
if err != nil {
log.Fatalf("%v.ListFeatures(_) = _, %v", client, err)
}
for {
feature, err := stream.Recv()
if err == io.EOF {
break
}
if err != nil {
log.Fatalf("%v.ListFeatures(_) = _, %v", client, err)
}
log.Println(feature)
}
```
As in simple RPC, we pass the method a context and a request. But instead of getting a response object back, we get back an instance of `RouteGuide_ListFeaturesClient`. The client can use the `RouteGuide_ListFeaturesClient` to read the server's responses. We use the `RouteGuide_ListFeaturesClient`'s `Recv()` 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 error `err` returned from `Recv()` after each call. If `nil`, the stream is still good and it can continue reading; if it's `io.EOF` then the message stream has ended; otherwise there must be an RPC error, which is passed over through `err`.
The client-side streaming method `RecordRoute` is similar, except that we only pass the method a context and get a `RouteGuide_RecordRouteClient` back, which has a `Send()` method that we can use to send requests to the server.
```go
func runRecordRoute(client pb.RouteGuideClient) {
// Create a random number of random points
r := rand.New(rand.NewSource(time.Now().UnixNano()))
pointCount := int(r.Int31n(100)) + 2 // Traverse at least two points
var points []*pb.Point
for i := 0; i < pointCount; i++ {
points = append(points, randomPoint(r))
}
log.Printf("Traversing %d points.", len(points))
stream, err := client.RecordRoute(context.Background())
if err != nil {
log.Fatalf("%v.RecordRoute(_) = _, %v", client, err)
}
for _, point := range points {
if err := stream.Send(point); err != nil {
log.Fatalf("%v.Send(%v) = %v", stream, point, err)
}
}
reply, err := stream.CloseAndRecv()
if err != nil {
log.Fatalf("%v.CloseAndRecv() got error %v, want %v", stream, err, nil)
}
log.Printf("Route summary: %v", reply)
}
```
Once we've finished writing our client's requests to the stream using `Send()`, we need to call `CloseAndRecv()` on the stream to let gRPC know that we've finished writing and are expecting to receive a response. We get our RPC status from the `err` returned from `CloseAndRecv()`. If the status is `nil`, then the first return value will be a valid server response.
Finally, let's look at our bidirectional streaming RPC `RouteChat()`. As in the case of `RecordRoute`, we only pass the method a context object. But in this case we get back a `RouteGuide_RouteChatClient`, which we can use to both write *and* read messages.
```go
stream, err := client.RouteChat(context.Background())
```
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!
To compile and run the server, assuming you are in the folder
`$GOPATH/src/google.golang.org/grpc/examples/route_guide`, simply:
```sh
$ go run server/server.go
```
Likewise, to run the client:
```sh
$ go run client/client.go
```

4
go/helloworld/helloworld.pb.go
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@ -66,7 +66,7 @@ func NewGreeterClient(cc *grpc.ClientConn) GreeterClient {
func (c *greeterClient) SayHello(ctx context.Context, in *HelloRequest, opts ...grpc.CallOption) (*HelloReply, error) {
out := new(HelloReply)
err := grpc.Invoke(ctx, "/helloworld.Greeter/sayHello", in, out, c.cc, opts...)
err := grpc.Invoke(ctx, "/helloworld.Greeter/SayHello", in, out, c.cc, opts...)
if err != nil {
return nil, err
}
@ -101,7 +101,7 @@ var _Greeter_serviceDesc = grpc.ServiceDesc{
HandlerType: (*GreeterServer)(nil),
Methods: []grpc.MethodDesc{
{
MethodName: "sayHello",
MethodName: "SayHello",
Handler: _Greeter_SayHello_Handler,
},
},

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java/javatutorial.md
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@ -0,0 +1,363 @@
#gRPC Basics: Java
This tutorial provides a basic Java 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 Java gRPC API to write a simple client and server for your service.
It assumes that you have read the [Getting started](https://github.com/grpc/grpc-common) guide and are familiar with [protocol buffers] (https://developers.google.com/protocol-buffers/docs/overview). Note that the example in this tutorial uses the [proto3](https://github.com/google/protobuf/releases) version of the protocol buffers language, which is currently in alpha release: you can see the [release notes](https://github.com/google/protobuf/releases) for the new version in the protocol buffers Github repository.
This isn't a comprehensive guide to using gRPC in Java: more reference documentation is coming soon.
## 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 [grpc/grpc-java/examples/src/main/java/io/grpc/examples](https://github.com/grpc/grpc-java/tree/master/examples/src/main/java/io/grpc/examples). To download the example, clone the `grpc-java` repository by running the following command:
```shell
$ git clone https://github.com/google/grpc-java.git
```
Then change your current directory to `grpc-java/examples`:
```shell
$ cd grpc-java/examples
```
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 [the Java quick start guide](https://github.com/grpc/grpc-common/tree/master/java).
## Defining the service
Our first step (as you'll know from [Getting started](https://github.com/grpc/grpc-common)) 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 [`grpc-java/examples/src/main/proto/route_guide.proto`](https://github.com/grpc/grpc-java/blob/master/examples/src/main/proto/route_guide.proto).
As we're generating Java code in this example, we've specified a `java_package` file option in our .proto:
```proto
option java_package = "io.grpc.examples";
```
This specifies the package we want to use for our generated Java classes. If no explicit `java_package` option is given in the .proto file, then by default the proto package (specified using the "package" keyword) will be used. However, proto packages generally do not make good Java packages since proto packages are not expected to start with reverse domain names. If we generate code in another language from this .proto, the `java_package` option has no effect.
To define a service, we specify a named `service` in the .proto file:
```proto
service RouteGuide {
...
}
```
Then we define `rpc` methods inside our 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.
```proto
// 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.
```proto
// 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 server-side streaming method by placing the `stream` keyword before the *request* type.
```proto
// 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.
```proto
// 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:
```proto
// 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 Java plugin. You need to use the [proto3](https://github.com/google/protobuf/releases) compiler in order to generate gRPC services
For simplicity, we've provided a [Gradle build file](https://github.com/grpc/grpc-java/blob/master/examples/build.gradle) 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](https://github.com/grpc/grpc-java) first):
```shell
../gradlew build
```
which actually runs:
[actual command]
Running this command generates the following files:
- `RouteGuideOuterClass.java`, which contains all the protocol buffer code to populate, serialize, and retrieve our request and response message types
- `RouteGuideGrpc.java` which contains (along with some other useful code):
- an interface for `RouteGuide` servers to implement, `RouteGuideGrpc.Service`, with all the methods defined in the `RouteGuide` service.
- *stub* classes that clients can use to talk to a `RouteGuide` server. These also implement the `RouteGuide` interface.
<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 [grpc-java/examples/src/main/java/io/grpc/examples/RouteGuideServer.java](https://github.com/grpc/grpc-java/blob/master/examples/src/main/java/io/grpc/examples/RouteGuideServer.java). Let's take a closer look at how it works.
### Implementing RouteGuide
As you can see, our server has a `RouteGuideService` class that implements the generated `RouteGuideGrpc.Service` interface:
```java
private static class RouteGuideService implements RouteGuideGrpc.RouteGuide {
...
}
```
#### Simple RPC
`RouteGuideService` 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`.
```java
@Override
public void getFeature(Point request, StreamObserver<Feature> responseObserver) {
responseObserver.onValue(getFeature(request));
responseObserver.onCompleted();
}
...
private Feature getFeature(Point location) {
for (Feature feature : features) {
if (feature.getLocation().getLatitude() == location.getLatitude()
&& feature.getLocation().getLongitude() == location.getLongitude()) {
return feature;
}
}
// No feature was found, return an unnamed feature.
return Feature.newBuilder().setName("").setLocation(location).build();
}
```
`getFeature()` takes two parameters:
- `Point`: the request
- `StreamObserver<Feature>`: a response observer, which is a special interface for the server to call with its response.
To return our response to the client and complete the call:
1. We construct and populate a `Feature` response object to return to the client, as specified in our service definition. In this example, we do this in a separate private `getFeature()` method.
2. We use the response observer's `onValue()` method to return the `Feature`.
3. We use the response observer's `onCompleted()` method to specify that we've finished dealing with the RPC.
#### Server-side streaming RPC
Next let's look at one of our streaming RPCs. `ListFeatures` is a server-side streaming RPC, so we need to send back multiple `Feature`s to our client.
```java
private final Collection<Feature> features;
...
@Override
public void listFeatures(Rectangle request, StreamObserver<Feature> responseObserver) {
int left = min(request.getLo().getLongitude(), request.getHi().getLongitude());
int right = max(request.getLo().getLongitude(), request.getHi().getLongitude());
int top = max(request.getLo().getLatitude(), request.getHi().getLatitude());
int bottom = min(request.getLo().getLatitude(), request.getHi().getLatitude());
for (Feature feature : features) {
if (!RouteGuideUtil.exists(feature)) {
continue;
}
int lat = feature.getLocation().getLatitude();
int lon = feature.getLocation().getLongitude();
if (lon >= left && lon <= right && lat >= bottom && lat <= top) {
responseObserver.onValue(feature);
}
}
responseObserver.onCompleted();
}
```
Like the simple RPC, this method gets a request object (the `Rectangle` in which our client wants to find `Feature`s) and a `StreamObserver` response observer.
This time, we get as many `Feature` objects as we need to return to the client (in this case, we select them from the service's feature collection based on whether they're inside our request `Rectangle`), and write them each in turn to the response observer using its `Write()` method. Finally, as in our simple RPC, we use the response observer's `onCompleted()` method to tell gRPC that we've finished writing responses.
#### Client-side streaming RPC
Now let's look at something a little more complicated: the client-side streaming method `RecordRoute`, where we get a stream of `Point`s from the client and return a single `RouteSummary` with information about their trip.
```java
@Override
public StreamObserver<Point> recordRoute(final StreamObserver<RouteSummary> responseObserver) {
return new StreamObserver<Point>() {
int pointCount;
int featureCount;
int distance;
Point previous;
long startTime = System.nanoTime();
@Override
public void onValue(Point point) {
pointCount++;
if (RouteGuideUtil.exists(getFeature(point))) {
featureCount++;
}
// For each point after the first, add the incremental distance from the previous point to
// the total distance value.
if (previous != null) {
distance += calcDistance(previous, point);
}
previous = point;
}
@Override
public void onError(Throwable t) {
logger.log(Level.WARNING, "Encountered error in recordRoute", t);
}
@Override
public void onCompleted() {
long seconds = NANOSECONDS.toSeconds(System.nanoTime() - startTime);
responseObserver.onValue(RouteSummary.newBuilder().setPointCount(pointCount)
.setFeatureCount(featureCount).setDistance(distance)
.setElapsedTime((int) seconds).build());
responseObserver.onCompleted();
}
};
}
```
As you can see, like the previous method types our method gets a `StreamObserver` response observer parameter, but this time it returns a `StreamObserver` for the client to write its `Point`s.
In the method body we instantiate an anonymous `StreamObserver` to return, in which we:
- Override the `onValue()` method to get features and other information each time the client writes a `Point` to the message stream.
- Override the `onCompleted()` method (called when the *client* has finished writing messages) to populate and build our `RouteSummary`. We then call our method's own response observer's `onValue()` with our `RouteSummary`, and then call its `onCompleted()` method to finish the call from the server side.
#### Bidirectional streaming RPC
Finally, let's look at our bidirectional streaming RPC `RouteChat()`.
```cpp
@Override
public StreamObserver<RouteNote> routeChat(final StreamObserver<RouteNote> responseObserver) {
return new StreamObserver<RouteNote>() {
@Override
public void onValue(RouteNote note) {
List<RouteNote> notes = getOrCreateNotes(note.getLocation());
// Respond with all previous notes at this location.
for (RouteNote prevNote : notes.toArray(new RouteNote[0])) {
responseObserver.onValue(prevNote);
}
// Now add the new note to the list
notes.add(note);
}
@Override
public void onError(Throwable t) {
logger.log(Level.WARNING, "Encountered error in routeChat", t);
}
@Override
public void onCompleted() {
responseObserver.onCompleted();
}
};
}
```
As with our client-side streaming example, we both get and return a `StreamObserver` response observer, except this time we return values via our method's response observer while the client is still writing messages to *their* message stream. 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:
```java
public void start() {
gRpcServer = NettyServerBuilder.forPort(port)
.addService(RouteGuideGrpc.bindService(new RouteGuideService(features)))
.build().start();
logger.info("Server started, listening on " + port);
...
}
```
As you can see, we build and start our server using a `NettyServerBuilder`. This is a builder for servers based on the [Netty](http://netty.io/) transport framework.
To do this, we:
1. Create an instance of our service implementation class `RouteGuideService` and pass it to the generated `RouteGuideGrpc` class's static `bindService()` method to get a service definition.
3. Specify the address and port we want to use to listen for client requests using the builder's `forPort()` method.
4. Register our service implementation with the builder by passing the service definition returned from `bindService()` to the builder's `addService()` method.
5. Call `build()` and `start()` on the builder to create and start an RPC server for our service.
<a name="client"></a>
## Creating the client
In this section, we'll look at creating a Java client for our `RouteGuide` service. You can see our complete example client code in [grpc-java/examples/src/main/java/io/grpc/examples/RouteGuideClient.java](https://github.com/grpc/grpc-java/blob/master/examples/src/main/java/io/grpc/examples/RouteGuideClient.java).
### Creating a stub
To call service methods, we first need to create a *stub*, or rather, two stubs:
- a *blocking/synchronous* stub: this means that the RPC call waits for the server to respond, and will either return a response or raise an exception.
- a *non-blocking/asynchronous* stub that makes non-blocking calls to the server, where the response is returned asynchronously. You can make certain types of streaming call only using the asynchronous stub.
First we need to create a gRPC *channel* for our stub, specifying the server address and port we want to connect to:
```java
channel = NettyChannelBuilder.forAddress(host, port)
.negotiationType(NegotiationType.PLAINTEXT)
.build();
```
Now we can use the channel to create our stubs using the `newStub` and `newBlockingStub` methods provided in the `RouteGuideGrpc` class we generated from our .proto.
```java
blockingStub = RouteGuideGrpc.newBlockingStub(channel);
asyncStub = RouteGuideGrpc.newStub(channel);
```
### Calling service methods
Now let's look at how we call our service methods.
#### Simple RPC
#### Server-side streaming RPC
#### Client-side streaming RPC
#### Bidirectional streaming RPC
## Try it out!
Follow the instructions in the example directory [README](https://github.com/grpc/grpc-java/blob/master/examples/README.md) to build and run the client and server.

20
node/README.md
Unescape View File

@ -10,37 +10,37 @@ INSTALL
-------
- Clone this repository
```sh
$ git clone https://github.com/grpc/grpc-common.git
```
- Follow the instructions in [INSTALL](https://github.com/grpc/grpc/blob/master/INSTALL) to install the gRPC C core.
- Install
- Install this package's dependencies
```sh
$ cd grpc-common/node
$ npm install
# If node is not found, you'll need to clone the grpc repository (if you haven't already)
$ npm install
# If grpc is not found, you'll need to install it from the grpc repository
$ git clone https://github.com/grpc/grpc.git
$ npm install ~/grpc/src/node
$ npm install path/to/grpc/src/node
```
Try it!
Try it!
-------
- Run the server
```sh
$ # from this directory
$ nodejs ./greeter_server.js &
$ # from this directory (grpc_common/node).
$ node ./greeter_server.js &
```
- Run the client
```sh
$ # from this directory
$ nodejs ./greeter_client.js
$ node ./greeter_client.js
```
Note

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Unescape View File

@ -0,0 +1,362 @@
#gRPC Basics: Node.js
This tutorial provides a basic Node.js programmer's introduction to working with gRPC. By walking through this example you'll learn how to:
- Define a service in a .proto file.
- Use the Node.js gRPC API to write a simple client and server for your service.
It assumes that you have read the [Getting started](https://github.com/grpc/grpc-common) guide and 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 see the [release notes](https://github.com/google/protobuf/releases) for the new version in the protocol buffers Github repository.
This isn't a comprehensive guide to using gRPC in Node.js: more reference documentation is coming soon.
## 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 [grpc/grpc-common/node/route_guide](https://github.com/grpc/grpc-common/tree/master/node/route_guide). To download the example, clone the `grpc-common` repository by running the following command:
```shell
$ git clone https://github.com/google/grpc-common.git
```
Then change your current directory to `grpc-common/node/route_guide`:
```shell
$ cd grpc-common/node/route_guide
```
You also should have the relevant tools installed to generate the server and client interface code - if yofu don't already, follow the setup instructions in [the Node.js quick start guide](https://github.com/grpc/grpc-common/tree/master/node).
## Defining the service
Our first step (as you'll know from [Getting started](https://github.com/grpc/grpc-common)) 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 [`grpc-common/protos/route_guide.proto`](https://github.com/grpc/grpc-common/blob/master/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 server-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;
}
```
## Loading service descriptors from proto files
The Node.js library dynamically generates service descriptors and client stub definitions from `.proto` files loaded at runtime.
To load a `.proto` file, simply `require` the gRPC library, then use its `load()` method to load the proto file:
```node
var grpc = require('grpc');
var protoDescriptor = grpc.load(__dirname + '/route_guide.proto');
// The protoDescriptor object has the full package hierarchy
var example = protoDescriptor.examples;
```
Then, the stub constructor is in the examples namespace (`protoDescriptor.examples.RouteGuide`) and the service descriptor (which is used to create a server) is a property of the stub (`protoDescriptor.examples.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 [grpc-common/node/route_guide/route_guide_server.js](https://github.com/grpc/grpc-common/blob/master/node/route_guide/route_guide_server.js). Let's take a closer look at how it works.
### Implementing RouteGuide
As you can see, our server has a `Server` constructor generated from the `RouteGuide.service` descriptor object
```node
var Server = grpc.buildServer([examples.RouteGuide.service]);
```
In this case we're implementing the *asynchronous* version of `RouteGuide`, which provides our default gRPC server behaviour.
The functions in `route_guide_server.js` implement 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`.
```node
function checkFeature(point) {
var feature;
// Check if there is already a feature object for the given point
for (var i = 0; i < feature_list.length; i++) {
feature = feature_list[i];
if (feature.location.latitude === point.latitude &&
feature.location.longitude === point.longitude) {
return feature;
}
}
var name = '';
feature = {
name: name,
location: point
};
return feature;
}
function getFeature(call, callback) {
callback(null, checkFeature(call.request));
}
```
The method is passed a call object for the RPC, which has the `Point` parameter as a property, and a callback to be passed the resulting `Feature`. In the method we populate a `Feature` corresponding to the given point and pass it to the callback, with a null first parameter to indicate that there is no error.
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.
```node
function listFeatures(call) {
var lo = call.request.lo;
var hi = call.request.hi;
var left = _.min([lo.longitude, hi.longitude]);
var right = _.max([lo.longitude, hi.longitude]);
var top = _.max([lo.latitude, hi.latitude]);
var bottom = _.min([lo.latitude, hi.latitude]);
// For each feature, check if it is in the given bounding box
_.each(feature_list, function(feature) {
if (feature.name === '') {
return;
}
if (feature.location.longitude >= left &&
feature.location.longitude <= right &&
feature.location.latitude >= bottom &&
feature.location.latitude <= top) {
call.write(feature);
}
});
call.end();
}
```
As you can see, instead of getting the call object and callback in our method parameters, this time we get a call object that implements the `Writable` interface. In the method, we create as many `Feature` objects as we need to return, writing them to the `call` using its `write()` method. Finally, we call `call.end()` to indicate that we have sent all messages.
If you look at the client-side streaming method `RecordRoute` you'll see it's quite similar to the unary call, except this time the `call` parameter implements the `Reader` interface. The `call`'s `'data'` event fires every time there is new data, and the `'end'` event fires when all data has been read. Like the unary case, we respond by calling the callback
```node
call.on('data', function(point) {
// Process user data
});
call.on('end', function() {
callback(null, result);
});
```
Finally, let's look at our bidirectional streaming RPC `RouteChat()`.
```node
function routeChat(call) {
call.on('data', function(note) {
var key = pointKey(note.location);
/* For each note sent, respond with all previous notes that correspond to
* the same point */
if (route_notes.hasOwnProperty(key)) {
_.each(route_notes[key], function(note) {
call.write(note);
});
} else {
route_notes[key] = [];
}
// Then add the new note to the list
route_notes[key].push(JSON.parse(JSON.stringify(note)));
});
call.on('end', function() {
call.end();
});
}
```
This time we get a `call` implementing `Duplex` 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:
```node
function getServer() {
return new Server({
'examples.RouteGuide' : {
getFeature: getFeature,
listFeatures: listFeatures,
recordRoute: recordRoute,
routeChat: routeChat
}
});
}
var routeServer = getServer();
routeServer.bind('0.0.0.0:50051');
routeServer.listen();
```
As you can see, we build and start our server with the following steps:
1. Create a `Server` constructor from the `RouteGuide` service descriptor.
2. Implement the service methods.
3. Create an instance of the server by calling the `Server` constructor with the method implementations.
4. Specify the address and port we want to use to listen for client requests using the instance's `bind()` method.
5. Call `listen()` on the instance to start the RPC server.
<a name="client"></a>
## Creating the client
In this section, we'll look at creating a Node.js client for our `RouteGuide` service. You can see our complete example client code in [grpc-common/node/route_guide/route_guide_client.js](https://github.com/grpc/grpc-common/blob/master/node/route_guide/route_guide_client.js).
### Creating a stub
To call service methods, we first need to create a *stub*. To do this, we just need to call the RouteGuide stub constructor, specifying the server address and port.
```node
new example.RouteGuide('localhost:50051');
```
### Calling service methods
Now let's look at how we call our service methods. Note that all of these methods are asynchronous: they use either events or callbacks to retrieve results.
#### Simple RPC
Calling the simple RPC `GetFeature` is nearly as straightforward as calling a local asynchronous method.
```node
var point = {latitude: 409146138, longitude: -746188906};
stub.getFeature(point, function(err, feature) {
if (err) {
// process error
} else {
// process feature
}
});
```
As you can see, we create and populate a request object. Finally, we call the method on the stub, passing it the request and callback. If there is no error, then we can read the response information from the server from our response object.
```node
console.log('Found feature called "' + feature.name + '" at ' +
feature.location.latitude/COORD_FACTOR + ', ' +
feature.location.longitude/COORD_FACTOR);
```
#### 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:
```node
var call = client.listFeatures(rectangle);
call.on('data', function(feature) {
console.log('Found feature called "' + feature.name + '" at ' +
feature.location.latitude/COORD_FACTOR + ', ' +
feature.location.longitude/COORD_FACTOR);
});
call.on('end', function() {
// The server has finished sending
});
call.on('status', function(status) {
// process status
});
```
Instead of passing the method a request and callback, we pass it a request and get a `Readable` stream object back. The client can use the `Readable`'s `'data'` event to read the server's responses. This event fires with each `Feature` message object until there are no more messages: the `'end'` event indicates that the call is done. Finally, the status event fires when the server sends the status.
The client-side streaming method `RecordRoute` is similar, except there we pass the method a callback and get back a `Writable`.
```node
var call = client.recordRoute(function(error, stats) {
if (error) {
callback(error);
}
console.log('Finished trip with', stats.point_count, 'points');
console.log('Passed', stats.feature_count, 'features');
console.log('Travelled', stats.distance, 'meters');
console.log('It took', stats.elapsed_time, 'seconds');
});
function pointSender(lat, lng) {
return function(callback) {
console.log('Visiting point ' + lat/COORD_FACTOR + ', ' +
lng/COORD_FACTOR);
call.write({
latitude: lat,
longitude: lng
});
_.delay(callback, _.random(500, 1500));
};
}
var point_senders = [];
for (var i = 0; i < num_points; i++) {
var rand_point = feature_list[_.random(0, feature_list.length - 1)];
point_senders[i] = pointSender(rand_point.location.latitude,
rand_point.location.longitude);
}
async.series(point_senders, function() {
call.end();
});
```
Once we've finished writing our client's requests to the stream using `write()`, we need to call `end()` on the stream to let gRPC know that we've finished writing. If the status is `OK`, the `stats` object 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 `Duplex` stream object, which we can use to both write and read messages.
```node
var call = client.routeChat();
```
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
$ npm install
```
Run the server, which will listen on port 50051:
```shell
$ node ./route_guide_server.js
```
Run the client (in a different terminal):
```shell
$ node ./route_guide_client.js
```

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@ -38,6 +38,9 @@ service RouteGuide {
// A simple RPC.
//
// Obtains the feature at a given position.
//
// A feature with an empty name is returned if there's no feature at the given
// position.
rpc GetFeature(Point) returns (Feature) {}
// A server-to-client streaming RPC.

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@ -0,0 +1 @@
*.pyc

111
python/helloworld/README.md
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# gRPC Python Hello World Tutorial
### Install gRPC
Make sure you have built gRPC Python from source on your system. Follow the instructions here:
[https://github.com/grpc/grpc/blob/master/src/python/README.md](https://github.com/grpc/grpc/blob/master/src/python/README.md).
This gives you a python virtual environment with installed gRPC Python
in GRPC_ROOT/python2.7_virtual_environment. GRPC_ROOT is the path to which you
have cloned the [gRPC git repo](https://github.com/grpc/grpc).
### Get the tutorial source code
The example code for this and our other examples live in the `grpc-common`
GitHub repository. Clone this repository to your local machine by running the
following command:
```sh
$ git clone https://github.com/google/grpc-common.git
```
Change your current directory to grpc-common/python/helloworld
```sh
$ cd grpc-common/python/helloworld/
```
### Defining a service
The first step in creating our example is to define a *service*: an RPC
service specifies the methods that can be called remotely with their parameters
and return types. As you saw in the
[overview](#protocolbuffers) above, gRPC does this using [protocol
buffers](https://developers.google.com/protocol-buffers/docs/overview). We
use the protocol buffers interface definition language (IDL) to define our
service methods, and define the parameters and return
types as protocol buffer message types. Both the client and the
server use interface code generated from the service definition.
Here's our example service definition, defined using protocol buffers IDL in
[helloworld.proto](https://github.com/grpc/grpc-common/blob/master/python/helloworld/helloworld.proto). The `Greeting`
service has one method, `hello`, that lets the server receive a single
`HelloRequest`
message from the remote client containing the user's name, then send back
a greeting in a single `HelloReply`. This is the simplest type of RPC you
can specify in gRPC.
```
syntax = "proto2";
// The greeting service definition.
service Greeter {
// Sends a greeting
rpc SayHello (HelloRequest) returns (HelloReply) {}
}
// The request message containing the user's name.
message HelloRequest {
optional string name = 1;
}
// The response message containing the greetings
message HelloReply {
optional string message = 1;
}
```
<a name="generating"></a>
### Generating gRPC code
Once we've defined our service, we use the protocol buffer compiler
`protoc` to generate the special client and server code we need to create
our application. The generated code contains both stub code for clients to
use and an abstract interface for servers to implement, both with the method
defined in our `Greeting` service.
To generate the client and server side interfaces:
```sh
$ ./run_codegen.sh
```
Which internally invokes the proto-compiler as:
```sh
$ protoc -I . --python_out=. --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_python_plugin` helloworld.proto
```
Optionally, you can just skip the code generation step as the generated python module has already
been generated for you (helloworld_pb2.py).
### The client
Client-side code can be found in [greeter_client.py](https://github.com/grpc/grpc-common/blob/master/python/helloworld/greeter_client.py).
You can run the client using:
```sh
$ ./run_client.sh
```
### The server
Server side code can be found in [greeter_server.py](https://github.com/grpc/grpc-common/blob/master/python/helloworld/greeter_server.py).
You can run the server using:
```sh
$ ./run_server.sh
```

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@ -0,0 +1,44 @@
# Copyright 2015, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""The Python implementation of the GRPC helloworld.Greeter client."""
import helloworld_pb2
_TIMEOUT_SECONDS = 10
def run():
with helloworld_pb2.early_adopter_create_Greeter_stub('localhost', 50051) as stub:
response = stub.SayHello(helloworld_pb2.HelloRequest(name='you'), _TIMEOUT_SECONDS)
print "Greeter client received: " + response.message
if __name__ == '__main__':
run()

56
python/helloworld/greeter_server.py
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@ -0,0 +1,56 @@
# Copyright 2015, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""The Python implementation of the GRPC helloworld.Greeter server."""
import time
import helloworld_pb2
_ONE_DAY_IN_SECONDS = 60 * 60 * 24
class Greeter(helloworld_pb2.EarlyAdopterGreeterServicer):
def SayHello(self, request, context):
return helloworld_pb2.HelloReply(message='Hello, %s!' % request.name)
def serve():
server = helloworld_pb2.early_adopter_create_Greeter_server(
Greeter(), 50051, None, None)
server.start()
try:
while True:
time.sleep(_ONE_DAY_IN_SECONDS)
except KeyboardInterrupt:
server.stop()
if __name__ == '__main__':
serve()

49
python/helloworld/helloworld.proto
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@ -0,0 +1,49 @@
// Copyright 2015, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
syntax = "proto2";
//TODO: see https://github.com/grpc/grpc/issues/814
//package examples;
// The greeting service definition.
service Greeter {
// Sends a greeting
rpc SayHello (HelloRequest) returns (HelloReply) {}
}
// The request message containing the user's name.
message HelloRequest {
optional string name = 1;
}
// The response message containing the greetings
message HelloReply {
optional string message = 1;
}

158
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@ -0,0 +1,158 @@
# Generated by the protocol buffer compiler. DO NOT EDIT!
# source: helloworld.proto
import sys
_b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode('latin1'))
from google.protobuf import descriptor as _descriptor
from google.protobuf import message as _message
from google.protobuf import reflection as _reflection
from google.protobuf import symbol_database as _symbol_database
from google.protobuf import descriptor_pb2
# @@protoc_insertion_point(imports)
_sym_db = _symbol_database.Default()
DESCRIPTOR = _descriptor.FileDescriptor(
name='helloworld.proto',
package='',
serialized_pb=_b('\n\x10helloworld.proto\"\x1c\n\x0cHelloRequest\x12\x0c\n\x04name\x18\x01 \x01(\t\"\x1d\n\nHelloReply\x12\x0f\n\x07message\x18\x01 \x01(\t23\n\x07Greeter\x12(\n\x08SayHello\x12\r.HelloRequest\x1a\x0b.HelloReply\"\x00')
)
_sym_db.RegisterFileDescriptor(DESCRIPTOR)
_HELLOREQUEST = _descriptor.Descriptor(
name='HelloRequest',
full_name='HelloRequest',
filename=None,
file=DESCRIPTOR,
containing_type=None,
fields=[
_descriptor.FieldDescriptor(
name='name', full_name='HelloRequest.name', index=0,
number=1, type=9, cpp_type=9, label=1,
has_default_value=False, default_value=_b("").decode('utf-8'),
message_type=None, enum_type=None, containing_type=None,
is_extension=False, extension_scope=None,
options=None),
],
extensions=[
],
nested_types=[],
enum_types=[
],
options=None,
is_extendable=False,
extension_ranges=[],
oneofs=[
],
serialized_start=20,
serialized_end=48,
)
_HELLOREPLY = _descriptor.Descriptor(
name='HelloReply',
full_name='HelloReply',
filename=None,
file=DESCRIPTOR,
containing_type=None,
fields=[
_descriptor.FieldDescriptor(
name='message', full_name='HelloReply.message', index=0,
number=1, type=9, cpp_type=9, label=1,
has_default_value=False, default_value=_b("").decode('utf-8'),
message_type=None, enum_type=None, containing_type=None,
is_extension=False, extension_scope=None,
options=None),
],
extensions=[
],
nested_types=[],
enum_types=[
],
options=None,
is_extendable=False,
extension_ranges=[],
oneofs=[
],
serialized_start=50,
serialized_end=79,
)
DESCRIPTOR.message_types_by_name['HelloRequest'] = _HELLOREQUEST
DESCRIPTOR.message_types_by_name['HelloReply'] = _HELLOREPLY
HelloRequest = _reflection.GeneratedProtocolMessageType('HelloRequest', (_message.Message,), dict(
DESCRIPTOR = _HELLOREQUEST,
__module__ = 'helloworld_pb2'
# @@protoc_insertion_point(class_scope:HelloRequest)
))
_sym_db.RegisterMessage(HelloRequest)
HelloReply = _reflection.GeneratedProtocolMessageType('HelloReply', (_message.Message,), dict(
DESCRIPTOR = _HELLOREPLY,
__module__ = 'helloworld_pb2'
# @@protoc_insertion_point(class_scope:HelloReply)
))
_sym_db.RegisterMessage(HelloReply)
import abc
from grpc._adapter import fore
from grpc._adapter import rear
from grpc.framework.assembly import implementations
from grpc.framework.assembly import utilities
class EarlyAdopterGreeterServicer(object):
"""<fill me in later!>"""
__metaclass__ = abc.ABCMeta
@abc.abstractmethod
def SayHello(self, request):
raise NotImplementedError()
class EarlyAdopterGreeterServer(object):
"""<fill me in later!>"""
__metaclass__ = abc.ABCMeta
@abc.abstractmethod
def start(self):
raise NotImplementedError()
@abc.abstractmethod
def stop(self):
raise NotImplementedError()
class EarlyAdopterGreeterStub(object):
"""<fill me in later!>"""
__metaclass__ = abc.ABCMeta
@abc.abstractmethod
def SayHello(self, request):
raise NotImplementedError()
SayHello.async = None
def early_adopter_create_Greeter_server(servicer, port, root_certificates, key_chain_pairs):
method_implementations = {
"SayHello": utilities.unary_unary_inline(servicer.SayHello),
}
import helloworld_pb2
request_deserializers = {
"SayHello": helloworld_pb2.HelloRequest.FromString,
}
response_serializers = {
"SayHello": lambda x: x.SerializeToString(),
}
link = fore.activated_fore_link(port, request_deserializers, response_serializers, root_certificates, key_chain_pairs)
return implementations.assemble_service(method_implementations, link)
def early_adopter_create_Greeter_stub(host, port):
method_implementations = {
"SayHello": utilities.unary_unary_inline(None),
}
import helloworld_pb2
response_deserializers = {
"SayHello": helloworld_pb2.HelloReply.FromString,
}
request_serializers = {
"SayHello": lambda x: x.SerializeToString(),
}
link = rear.activated_rear_link(host, port, request_serializers, response_deserializers)
return implementations.assemble_dynamic_inline_stub(method_implementations, link)
# @@protoc_insertion_point(module_scope)

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@ -0,0 +1,8 @@
#!/bin/bash
# This is where you have cloned out the https://github.com/grpc/grpc repository
# And built gRPC Python.
# ADJUST THIS PATH TO WHERE YOUR ACTUAL LOCATION IS
GRPC_ROOT=~/github/grpc
$GRPC_ROOT/python2.7_virtual_environment/bin/python greeter_client.py

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python/helloworld/run_codegen.sh
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@ -0,0 +1,4 @@
#!/bin/bash
# Runs the protoc with gRPC plugin to generate protocol messages and gRPC stubs.
protoc -I . --python_out=. --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_python_plugin` helloworld.proto

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@ -0,0 +1,9 @@
#!/bin/bash
# This is where you have cloned out the https://github.com/grpc/grpc repository
# And built gRPC Python.
# ADJUST THIS PATH TO WHERE YOUR ACTUAL LOCATION IS
GRPC_ROOT=~/github/grpc
$GRPC_ROOT/python2.7_virtual_environment/bin/python greeter_server.py

2
ruby/Gemfile
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@ -4,7 +4,7 @@
source 'https://rubygems.org/'
# Update this to reflect the local installation of gRPC.
gem 'grpc', path: '/usr/local/google/repos/grpc/src/ruby'
gem 'grpc', path: '~/grpc/src/ruby'
# TODO: fix this if/when the gRPC repo structure changes.
#

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ruby/README.md
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@ -1,6 +1,10 @@
gRPC in 3 minutes (Ruby)
========================
BACKGROUND
-------------
For this sample, we've already generated the server and client stubs from [helloworld.proto](https://github.com/grpc/grpc-common/blob/master/protos/helloworld.proto).
PREREQUISITES
-------------

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