grpc-kit

grpc-kit

Use grpc more simply on Node.js.

quick start

install

$ npm install grpc @grpc/proto-loader grpc-kit

proto

syntax="proto3";

package greeter;

service Greeter {
  rpc Hello (RequestGreet) returns (ResponseGreet) {}
  rpc Goodbye (RequestGreet) returns (ResponseGreet) {}
}

message RequestGreet {
  string name = 1;
}

message ResponseGreet {
  string message = 1;
}

Server

const {createServer} = require("grpc-kit");
const server = createServer();

server.use({
  protoPath: "/path/to/greeter.proto",
  packageName: "greeter",
  serviceName: "Greeter",
  routes: {
    hello: (call, callback) => {
      callback(null, { message: `Hello, ${call.request.name}` });
    },
    goodbye: async (call) => {
      return { message: `Goodbye, ${call.request.name}` };
    }
  },
  options: {
    keepCase: true,
    longs: String,
    enums: String,
    defaults: true,
    oneofs: true
  }
});
server.listen("0.0.0.0:50051");

Client

const {createClient} = require("grpc-kit");
const client = createClient({
  protoPath: "/path/to/greeter.proto",
  packageName: "greeter",
  serviceName: "Greeter",
  options: {
    keepCase: true,
    longs: String,
    enums: String,
    defaults: true,
    oneofs: true
  }
}

}, "0.0.0.0:50051");

client.hello({ name: "Jack" }, (err, { message }) => {
  if(err) throw err;
  console.log(message);
});

client.goodbye({ name: "John" }, (err, { message }) => {
  if(err) throw err;
  console.log(message);
});

use stream

proto

syntax="proto3";

package stream_greeter;

service StreamGreeter {
  rpc ClientStreamHello(stream Message) returns(Message) {}
  rpc ServerStreamHello(Message) returns(stream Message) {}
  rpc MutualStreamHello (stream Message) returns (stream Message) {}
}

message Message {
  string message = 1;
}

Server

const {createServer} = require("grpc-kit");
const server = createServer();

server.use({
  protoPath: "/path/to/stream_greeter.proto"),
  packageName: "stream_greeter",
  serviceName: "StreamGreeter",
  routes: {
    clientStreamHello: (call, callback) => {
      call.on("data", (chunk) => {
        //exec when client wrote message
        console.log(chunk.message);
      });
      call.on("end", (chunk) => {
        callback(null, { message: "Hello! I'm fine, thank you!" })
      });
    },

    serverStreamHello: (call) => {
      console.log(call.request.message);
      call.write({ message: "Hello!" });
      call.write({ message: "I'm fine, thank you" });
      call.end();
    },

    mutualStreamHello: (call) => {
      call.on("data", (chunk) => {
        //exec when client wrote message
        console.log(chunk.message);
        if(chunk.message === "Hello!"){
          call.write({ message: "Hello!" });
        } else if(chunk.message === "How are you?"){
          call.write({ message: "I'm fine, thank you" });
        } else {
          call.write({ message: "pardon?" });
        }
      });
      call.on("end", (chunk) => {
        call.end();
      });
    }
  }
});

server.listen("0.0.0.0:50051");

Client

const {createClient} = require("grpc-kit");
const client = createClient({
  protoPath: "/path/to/stream_greeter.proto",
  packageName: "stream_greeter",
  serviceName: "StreamGreeter"
}, "0.0.0.0:50051");

client stream

const call = client.clientStreamHello((err, res) => {
  if(err) throw err;
  console.log(res.message);
});
call.write({ message: "Hello!" });
call.write({ message: "How are you?" });
call.end();

server stream

const call = client.serverStreamHello({ message: "Hello! How are you?" });
call.on("data", (chunk) => {
  console.log(chunk.message);
});
call.on("end", () => {
  //exec when server streaming ended.
});

mutual stream

const call = client.mutualStreamHello();
call.on("data", (chunk) => {
  console.log(chunk.message);
});
call.on("end", () => {
  //exec when server streaming ended.
});
call.write({ message: "Hello!" });
call.write({ message: "How are you?" });
call.end();

api

createServer(): GrpcServer

Create GrpcServer instance. GrpcServer is a wrapper class of grpc.Server providing simplified api to register services.

GrpcServer.use({protoPath,packageName,serviceName,options,routes}): GrpcServer

Register a service to provide from a server.

arg name	type	required/optional	description
protoPath	String	Required	path to .proto file
packageName	String	Required	name of package
serviceName	String	Required	name of service
options	@grpc/proto-loader.Options	Optional	options for @grpc/proto-loader to load .proto file. In detail, please check here out. Default is null
routes	{ [methodName]:(call, callback) => void | (call) => Promise }	Required	routing map consists of a set of pair of method name and handler. Both of sync function and async function are available as a handler

GrpcServer.listen(address_port, credentials): GrpcServer

Start server. Alias to grpc.Server.bind() and grpc.Server.start().

arg name	type	required/optional	description
address_port	String	Required	address and port of server to listen
credentials	grpc.ServerCredentials	Optional	grpc server credentials. Default to insecure credentials generated by grpc.ServerCredentials.createInsecure()

GrpcServer.close(force, callback): GrpcServer

Close server. Alias to grpc.Server.tryShutdown() and grpc.Server.forceShutdown.

arg name	type	required/optional	description
force	Boolean	Optional	flag if force shutdown or not. Default to false
callback	()=>{}	Optional	call when shutdown completed. available only when force is false

createClient({protoPath,packageName,serviceName,options},address_port,credentials): grpc.Client

Create grpc.Client instance.

arg name	type	required/optional	description
protoPath	String	Required	path to .proto file
packageName	String	Required	name of package
serviceName	String	Required	name of service
options	@grpc/proto-loader.Options	Optional	options for @grpc/proto-loader to load .proto file. In detail, please check here out. Default is null
address_port	String	Required	address and port of server to listen
credentials	grpc.ChannelCredentials	Optional	grpc channel credentials. Default to insecure credentials generated by grpc.credentials.createInsecure()