Build a Cloud‑Native Redis Pub/Sub App with Dapr, Docker Compose, and NestJS

Overview

Dapr (Distributed Application Runtime) is a portable, event‑driven runtime that enables resilient stateless or stateful applications to run on cloud or edge platforms and supports multiple languages and frameworks.

Step‑by‑step implementation

1. Create project directory

mkdir dapr-nestjs-redis-pub-sub

2. Initialise Docker Compose

Create docker-compose.yml in the project root.

version: "3.5"
services:
  dapr-placement:
    image: "daprio/dapr"
    command: ["./placement","-port","50006"]

The placement service manages Dapr actor routing and acts as a message broker for the runtime.

3. Add Redis publisher service

redis-publisher:
    image: redis
    restart: always
    depends_on:
      - dapr-placement

4. Define Dapr Pub/Sub component

mkdir -p dapr/components
cd dapr/components
cat > redis-pubsub.yaml <<'EOF'
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: redis-pubsub
  namespace: default
spec:
  type: pubsub.redis
  version: v1
  metadata:
    - name: redisHost
      value: redis-publisher:6379
    - name: redisPassword
      value: ""
EOF

This component tells Dapr to use the Redis instance at redis-publisher:6379 for Pub/Sub.

5. Add Redis Dapr sidecar

redis-dapr-sidecar:
    image: "daprio/daprd:edge"
    command: [
      "./daprd",
      "-app-id","redis-publisher",
      "-app-port","6379",
      "-dapr-http-port","5000",
      "-components-path","/components",
      "-placement-host-address","dapr-placement:50006"
    ]
    volumes:
      - "./dapr/components/:/components"
    depends_on:
      - redis-publisher
    network_mode: "service:redis-publisher"

The sidecar forwards traffic from the Redis container to Dapr and registers the component.

6. Create NestJS subscriber service

npm i -g @nestjs/cli
nest new nest-subscriber

Use yarn as the package manager. Replace src/app.controller.ts with:

import { Controller, Post, Body } from '@nestjs/common';
import { AppService } from './app.service';

@Controller()
export class AppController {
  constructor(private readonly appService: AppService) {}

  @Post('/redis-publisher')
  async postRedisPub(@Body() reqBody) {
    console.log(`Redis published ${JSON.stringify(reqBody)}`);
    return `NestJS subscriber received ${reqBody} publish`;
  }
}

7. Dockerfile for NestJS server

FROM node:16.13.0-alpine
WORKDIR "/app"
COPY ./nest-subscriber/package.json ./
RUN yarn install
COPY ./nest-subscriber .
RUN yarn run build
EXPOSE 3000
CMD ["yarn","start:prod"]

8. Add NestJS service to Docker Compose

nest-subscriber:
    image: "nest-subscriber:latest"
    depends_on:
      - redis-publisher
      - dapr-placement
    restart: always

9. Create Dapr subscription

mkdir -p dapr/subscriptions
cd dapr/subscriptions
cat > redis-subscription.yaml <<'EOF'
apiVersion: dapr.io/v1alpha1
kind: Subscription
metadata:
  name: nest-redis-sub
spec:
  topic: nest-redis-pub-topic
  route: /redis-publisher
  pubsubname: redis-pubsub
  scopes:
    - nest-subscriber
EOF

The subscription instructs Dapr to invoke /redis-publisher on the NestJS service whenever the topic nest-redis-pub-topic is published.

10. Add sidecar for NestJS subscriber

nest-subscriber-dapr-sidecar:
    image: "daprio/daprd:edge"
    command: [
      "./daprd",
      "-app-id","nest-subscriber",
      "-app-port","3000",
      "-components-path","/components",
      "-placement-host-address","dapr-placement:50006"
    ]
    volumes:
      - "./dapr/components/:/components"
    depends_on:
      - nest-subscriber
    network_mode: "service:nest-subscriber"

11. Test the flow

curl --location --request POST 'http://localhost:5001/v1.0/publish/redis-pubsub/nest-redis-pub-topic' \
  --header 'Content-Type: application/json' \
  --data-raw '{"hello":"world"}'

Dapr forwards the request to the Redis sidecar, which publishes the message. Initially the NestJS subscriber receives an empty JSON object ( {}).

12. Enable NestJS to parse CloudEvents JSON

yarn add body-parser

import * as bodyParser from 'body-parser';
...
app.use(bodyParser.json({ type: 'application/cloudevents+json' }));
app.use(bodyParser.json());

After adding the parser, the subscriber correctly processes the CloudEvents payload and logs the received message.

13. Full docker‑compose.yaml

version: "3.5"
services:
  dapr-placement:
    image: "daprio/dapr"
    command: ["./placement","-port","50006"]

  redis-publisher:
    image: redis
    depends_on:
      - dapr-placement
    restart: always
    ports:
      - 5001:5000

  redis-dapr-sidecar:
    image: "daprio/daprd:edge"
    command: [
      "./daprd",
      "-app-id","redis-publisher",
      "-app-port","6379",
      "-dapr-http-port","5000",
      "-components-path","/components",
      "-placement-host-address","dapr-placement:50006"
    ]
    volumes:
      - "./dapr/components/:/components"
    depends_on:
      - redis-publisher
    network_mode: "service:redis-publisher"

  nest-subscriber:
    image: "nest-subscriber:latest"
    depends_on:
      - redis-publisher
      - dapr-placement
    restart: always

  nest-subscriber-dapr-sidecar:
    image: "daprio/daprd:edge"
    command: [
      "./daprd",
      "-app-id","nest-subscriber",
      "-app-port","3000",
      "-components-path","/components",
      "-placement-host-address","dapr-placement:50006"
    ]
    volumes:
      - "./dapr/components/:/components"
    depends_on:
      - nest-subscriber
    network_mode: "service:nest-subscriber"

Source code

https://github.com/Hacker-Linner/dapr-nestjs-redis-pub-sub.git