CODEWITHSUNDEEP
node.jsmicroservicesnestjs
Jeanluca Scaljeri
Jeanluca Scaljeri

Reputation: 29129

Call my NestJs microservice with nodeJS app

I think I can say I'm a bit of a noob with microservices. So, which is why I wanted to play with it. I used NestJs, because it looked easy

First I created a new app with nest new myservice Then I copied from the microservice docs the example main.ts and controller.ts into the project:

main.ts:

import { NestFactory } from '@nestjs/core';
import { Transport } from '@nestjs/microservices';
import { AppModule } from './app.module';

async function bootstrap() {
    const app = await NestFactory.createMicroservice(AppModule, {
        transport: Transport.TCP,
        options: { host: 'localhost', port: 3005 },
    });
    app.listen(() => console.log('Microservice is listening'));
}
bootstrap();

app.module.ts

import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';

@Module({
    imports: [],
    controllers: [AppController],
    providers: [AppService],
})
export class AppModule {

controoler.ts

import { Controller } from '@nestjs/common';
import { MessagePattern } from '@nestjs/microservices';

@Controller()
export class AppController {
    @MessagePattern({ cmd: 'sum' })
    accumulate(data: number[]): number {
        return (data || []).reduce((a, b) => a + b);
    }
}

Now when I start it, all looks well:

✗ yarn start
yarn run v1.13.0
$ ts-node -r tsconfig-paths/register src/main.ts
[Nest] 45783   - 05/01/2019, 11:08 PM   [NestFactory] Starting Nest application...
[Nest] 45783   - 05/01/2019, 11:08 PM   [InstanceLoader] AppModule dependencies initialized +17ms
[Nest] 45783   - 05/01/2019, 11:08 PM   [NestMicroservice] Nest 
microservice successfully started 
Microservice is listening

So, if anything is wrong here, please let me know! But know I would like to write a small test nodejs app that can call/communicate with this microservice. Any suggestion where to start with that. Can I use axios for example or should I use something else. Any help would be appreciated!

Upvotes: 3

Views: 4385

Answers (2)

Pablo Cid
Pablo Cid

Reputation: 76

I tried to communicate express app with nodejs microservice following the last post (Aleksandr Yatsenko) and works OK only if you install on your express app:

  • @nestjs/microservices
  • @nestjs/commons
  • @nestjs/core
  • rxjs

Here is the code:

const express = require('express')
const app = express()
const port = 3002
const { ClientTCP } = require('@nestjs/microservices');
const { lastValueFrom } = require('rxjs');

(async () => {
    const client = new ClientTCP({
        host: 'localhost',
        port: 3001,
    });

    await client.connect();

    app.get('/', async (req, res) => {
        const pattern = { cmd: 'sum' };
        const data = JSON.parse(req.query.data)

        const result = await lastValueFrom(client.send(pattern, data))

        res.json({ result })
    })

    app.listen(port, () => {
        console.log(`Example app listening at http://localhost:${port}`)
    })

})();

Upvotes: 1

Aleksandr Yatsenko
Aleksandr Yatsenko

Reputation: 869

You need to do the following.

import { ClientTCP } from '@nestjs/microservices';

(async () => {
    const client = new ClientTCP({
        host: 'localhost',
        port: 3005,
    });

    await client.connect();

    const pattern = { cmd: 'sum' };
    const data = [2, 3, 4, 5];

    const result = await client.send(pattern, data).toPromise();
    console.log(result);
})();

Upvotes: 9

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