gRPC Microservices example using nest.js and asp.net core microservices and nest.js based gateway API to consume in client app.
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Micorservices example using gRPC. Two microservices written in nest.js and ASP.NET Core using gRPC. Both of them connect to the gateway API (written in nest.js) using common proto file interfaces. No need to install Redis or RabbitMQ etc. as communication happen on RPC.
gRPC is a modern open source high performance Remote Procedure Call (RPC) framework that can run in any environment. It can efficiently connect services in and across data centers with pluggable support for load balancing, tracing, health checking and authentication. It is also applicable in last mile of distributed computing to connect devices, mobile applications and browsers to backend services.
In gRPC, a communication pattern describes how messages are encoded and interpreted between the client and server. There are several communication patterns in gRPC, such as the following:
- Unary RPC: A client submits only one request and receives only one response in unary RPC.
- Server streaming: A client transmits a request to the server and receives streams of messages in response. The server provides a status message once all data is transmitted.
- Client-streaming: Unlike server-streaming, client-streaming involves a client sending a stream of messages to a server. After the messages are sent, the client awaits the server's response.
- Bidirectional-streaming: Bidirectional streaming allows clients and servers to exchange messages in any order.
NestJS is a framework for building efficient, scalable Node.js web applications. It uses modern JavaScript and is built with TypeScript. If you develop an API built with TypeScript, then NestJS is the way to go! It’s heavily inspired by Spring and Angular.
An API gateway is an entry point for all clients, in our case, for all client requests based on HTTP, but it doesn’t need to be limited to HTTP only. The API gateway handles requests in one of two ways. Some requests are simply proxied/routed to the appropriate service. It handles other requests by fanning out to multiple services
Here is the outline we are going to do -
- Common proto folder with proto files
- nest.js microservice
- .NET core microservice
- nest.js gateway
grpc-nest-proto
$ cd grpc-nest-proto
$ npm init --y
$ git init
$ mkdir proto
$ touch proto/book.proto && touch proto/greet.proto
$ code .
Now we have the proto folder and two files book.proto and greet.proto available. We are going to use book.proto in nest.js microservice and greet.proto in .NET Core microservice.
//book.proto
syntax = "proto3";
package book;
service BookService {
rpc getBooks (getBooksRequest) returns (getBooksResponse) {}
rpc getBookById (getBookByIdRequest) returns (getBookByIdResponse) {}
}
// getBooks
message getBooksRequest{
}
message getBooksResponse {
repeated Book books = 1;
}
message Book {
int32 id =1;
string title = 2;
string description = 3;
string author = 4;
}
// getBookById
message getBookByIdRequest {
int32 id = 1;
}
message getBookByIdResponse {
Book book =1;
}
Book.proto has two methods to implement. getBooks and getBookById.
// Greet.proto
syntax = "proto3";
option csharp_namespace = "aspnetcore_api";
package greet;
// The greeting service definition.
service Greeter {
// Sends a greeting
rpc SayHello (HelloRequest) returns (HelloReply);
}
// The request message containing the user's name.
message HelloRequest {
string name = 1;
}
// The response message containing the greetings.
message HelloReply {
string message = 1;
}
Greet.proto will be used in .NET core microservice and it has one method to just greet hello {message}
Package.json We have to install some dependencies to compile these two proto files into pure *.ts file so that our gateway API can understand these contracts.(i.e. methods)
npm install @nestjs/microservices
npm install rxjs
npm install ts-proto
We are also going to add some scripts to compile the files.
"proto:book": "protoc --plugin=node_modules/.bin/protoc-gen-ts_proto -I=../grpc-nest-proto/proto --ts_proto_out=src/book/ ../grpc-nest-proto/proto/book.proto --ts_proto_opt=nestJs=true --ts_proto_opt=fileSuffix=.pb",
"proto:greet": "protoc --plugin=node_modules/.bin/protoc-gen-ts_proto -I=../grpc-nest-proto/proto --ts_proto_out=src/greet/ ../grpc-nest-proto/proto/greet.proto --ts_proto_opt=nestJs=true --ts_proto_opt=fileSuffix=.pb",
"proto:all": "npm run proto:book && npm run proto:greet"
NOTE: If you see some issues running these script and compiling your proto files, then you can download proto compiler and compile your files.
// here is how i run this commmand in windows powershell
>$nestjs-microservice-gRPC\grpc-nest-proto> ..\protoc-3.20.0-win64\bin\protoc.exe --plugin=./node_modules/.bin/protoc-gen-ts_proto.cmd --ts_proto_out=./build ./proto/*.proto --ts_proto_opt=nestJs=true --ts_proto_opt=fileSuffix=.pb
ok, so now we have proto files (i.e. contracts) ready to start with. We are going to make our first microservice using nest.js.
grpc-nest-book-svc
$ cd grpc-nest-book-svc
$ code .
$ npm i @nestjs/microservices @grpc/grpc-js @grpc/proto-loader @nestjs/typeorm typeorm pg class-transformer class-validator
$ npm i -D @types/node ts-proto
$ nest g mo book && nest g co book --no-spec && nest g s book --no-spec
Now, let's start with bootstrapping-
main.ts
async function bootstrap() {
const app = await NestFactory.createMicroservice(BookModule, {
transport: Transport.GRPC,
options: {
url: '0.0.0.0:50051',
protoPath: './../grpc-nest-proto/proto/book.proto',
package: 'book',
},
});
// tslint:disable-next-line: no-console
app.listen();
}
books.mocks.ts
Add dummy mock data for books - mock books data
book.controller.ts
@Controller('book')
export class BookController {
constructor(private readonly bookService: BookService) {}
@GrpcMethod('BookService','getBooks')
@Get()
async getBooks(getBooksRequest): Promise<getBooksResponse> {
return { books: await this.bookService.getBooks() }
}
@GrpcMethod('BookService','getBookById')
@Get(':id')
async getBookById(id:number): Promise<getBookByIdResponse> {
return {book: await this.bookService.getBookById(id)}
}
}
book.service.ts
import { getBooksResponse,Book } from '../../grpc-nest-proto/build/proto/book.pb';
import { Injectable, HttpException } from '@nestjs/common';
import { GrpcMethod } from '@nestjs/microservices';
import { BOOKS } from './books.mock';
@Injectable()
export class BookService {
books = BOOKS;
getBooks(): Promise<Book[]> {
return new Promise(resolve => {
resolve(this.books);
});
}
getBookById(param): Promise<Book> {
console.log(param);
return new Promise(resolve => {
const book = this.books.find($book => $book.id === param.id);
if (!book) {
throw new HttpException('Book does not exist!', 404);
}
resolve(book);
});
}
}
Build and Run this microservice
npm run start:dev
Testing using Postman
prerequisite
C# for VSCode -optional if you use .NET IDE
Create new project
dotnet new grpc -o aspnetcore-api
dotnet dev-certs https --trust
Here is how we are going to use our SayHello contract from greet.proto file
public override Task<HelloReply> SayHello(HelloRequest request, ServerCallContext context)
{
return Task.FromResult(new HelloReply
{
Message = "Hello " + request.Name
});
}
Important files to check or take a look
Program.cs
Appsettings.json
proto/greet.proto (same as our generic grpc-nest-proto folder. You can even refer it from there)
Testing using Postman
API Gateway is going to communicate with both of our microservices. It will be regular http based API which will handle request and responses to/from these microservices. It will use gRPC communication channel to talk to these microservices.
Gateway will have two sub-module
- Book
- controller.ts'
- This will have basic request and response middle man method
- module.ts
- This is where we are going to consume that nest.js book service on grpc channel
- book.pb.ts (compiled book.proto file)
- controller.ts'
- Greet
- controller.ts
- module.ts
- This is where we are going to consume that asp.net greet service on grpc channel
- greet.pb.ts (compiled greet.proto file)
Testing using Postman
- https://docs.nestjs.com/microservices/grpc#sample-grpc-service
- https://levelup.gitconnected.com/nestjs-microservices-with-grpc-api-gateway-and-authentication-part-1-2-650009c03686
- https://levelup.gitconnected.com/nestjs-microservices-with-grpc-api-gateway-and-authentication-part-2-2-d67dc8e3b86a
- https://mariobuonomo.dev/blog/tutorial-nestjs-microservices-grpc
- https://medium.com/effective-development/building-grpc-api-in-nest-with-typescript-95e1915abc15
- https://www.codemag.com/Article/2212071/A-Deep-Dive-into-Working-with-gRPC-in-.NET-6
Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.
If you have a suggestion that would make this better, please fork the repo and create a pull request. You can also simply open an issue with the tag "enhancement". Don't forget to give the project a star! Thanks again!
- Fork the Project
- Create your Feature Branch (
git checkout -b feature/AmazingFeature) - Commit your Changes (
git commit -m 'Add some AmazingFeature') - Push to the Branch (
git push origin feature/AmazingFeature) - Open a Pull Request
Distributed under the MIT License. See LICENSE.txt for more information.
Bhavin Patel
Project Link: https://github.com/itsmebhavin/nestjs-microservices-gRPC-example
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