Keycloak Token Validation Error in NestJS Application with Docker

I am encountering an issue with Keycloak integration in my NestJS application. My environment uses Docker for orchestrating services. Here is an overview of my configuration and relevant files:

Context

• Dockerfile:

  FROM node:18-alpine
  
  WORKDIR /app
  
  COPY package.json ./
  COPY package-lock.json ./
  
  RUN npm install
  
  COPY . .
  
  RUN npx prisma generate
  RUN npm run build
  
  EXPOSE 3000
  
  CMD ["node", "dist/main.js"]
  

• docker-compose.yml:

  version: '3.8'
  services:
    nest-app:
      build:
        context: .
        dockerfile: Dockerfile
      ports:
        - "3000:3000"
      environment:
        DATABASE_URL: "postgresql://postgres:postgres@postgres:5432/mydatabase"
      depends_on:
        postgres:
          condition: service_healthy
      networks:
        - my-network
  
    postgres:
      image: postgres:latest
      environment:
        POSTGRES_USER: postgres
        POSTGRES_PASSWORD: postgres
        POSTGRES_DB: mydatabase
      ports:
        - "5432:5432"
      volumes:
        - postgres_data:/var/lib/postgresql/data
      networks:
        - my-network
      healthcheck:
        test: ["CMD-SHELL", "pg_isready -U postgres"]
        interval: 10s
        timeout: 5s
        retries: 5
  
    keycloak:
      image: quay.io/keycloak/keycloak:latest
      environment:
        DB_VENDOR: h2
        KEYCLOAK_ADMIN: admin
        KEYCLOAK_ADMIN_PASSWORD: admin
        KEYCLOAK_IMPORT: /tmp/realm.json
      ports:
        - "8081:8080"
      volumes:
        - ./realm.json:/tmp/realm.json
      entrypoint: ["/opt/keycloak/bin/kc.sh"]
      command: ["start-dev"]
      networks:
        - my-network
  
  volumes:
    postgres_data:
  
  networks:
    my-network:
      driver: bridge
  

• app.module.ts:

  import { Module } from '@nestjs/common';
  import { ConfigModule } from '@nestjs/config';
  import {
    AuthGuard,
    KeycloakConnectModule,
    ResourceGuard,
    RoleGuard,
  } from 'nest-keycloak-connect';
  import { AppController } from './app.controller';
  import { AppService } from './app.service';
  import { PrismaModule } from './prisma.module';
  import { APP_GUARD } from '@nestjs/core';
  
  @Module({
    imports: [
      ConfigModule.forRoot({
        isGlobal: true,
      }),
      PrismaModule,
      KeycloakConnectModule.register({
        authServerUrl: 'http://127.0.0.1:8081/',
        realm: 'test',
        clientId: 'my-nest-project',
        secret: 'GSLUjhMMctvip6B01q3g7xu6P8SJBvT6', // or `credentials.secret` if used
      }),
    ],
    controllers: [AppController],
    providers: [
      AppService,
      {
        provide: APP_GUARD,
        useClass: AuthGuard,
      },
      {
        provide: APP_GUARD,
        useClass: ResourceGuard,
      },
      {
        provide: APP_GUARD,
        useClass: RoleGuard,
      },
    ],
  })
  export class AppModule {}
  

• app.service.ts:

  import { Injectable } from '@nestjs/common';
  
  @Injectable()
  export class AppService {
    getHello(): string {
      return 'Hello, World!';
    }
  
    getProtectedMessage(): string {
      return 'This is a protected route';
    }
  
    getTestMessage(): string {
      return 'This is a test route';
    }
  }
  

• main.ts:

  import { NestFactory } from '@nestjs/core';
  import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
  import { AppModule } from './app.module';
  import { PrismaService } from './prisma.service';
  
  async function bootstrap() {
    const app = await NestFactory.create(AppModule);
  
    // Swagger configuration
    const config = new DocumentBuilder()
      .setTitle('API Documentation')
      .setDescription('The API description')
      .setVersion('1.0')
      .addBearerAuth()
      .addTag('app')
      .addTag('hello')
      .build();
    const document = SwaggerModule.createDocument(app, config);
    SwaggerModule.setup('api', app, document);
  
    const prismaService = app.get(PrismaService);
    await prismaService.enableShutdownHooks(app);
  
    await app.listen(3000);
  }
  bootstrap();
  

Issue

When using Keycloak with my NestJS application, I get the following error in the Keycloak logs:

WARN [Keycloak] Cannot validate access token: Error: Grant validation failed. Reason: invalid token (wrong ISS)

API Calls

• Public Endpoints:

  • GET http://localhost:3000/ (works correctly)
  • GET http://localhost:3000/test (works correctly)
  • GET http://localhost:3000/hello (works correctly)
  • GET http://localhost:8081/realms/test (works correctly)

• Get Token from Keycloak: (works correctly)

  • POST http://localhost:8081/realms/test/protocol/openid-connect/token

• Access Protected Route with Bearer Token: (fails with 401 Unauthorized)

  • GET http://localhost:3000/protected

What I Tried

**Valid Token Check:
**
I used the Keycloak admin interface to get a token and tried accessing the protected route.
Expected: Successful access to the protected route with the valid token.
Actual Result: Received a 401 Unauthorized response.

Different authServerUrl Configurations:

I tested various configurations for authServerUrl in app.module.ts:

• http://127.0.0.1:8081/
• http://127.0.0.1:8081/auth
• http://localhost:8081/auth

Expected: Proper token validation and successful access to the protected route.
Actual Result: The same 401 Unauthorized response with the wrong ISS error.

Recreating the Keycloak Realm:
I attempted to recreate the Keycloak realm to ensure no configuration issues.
Expected: Correctly configured realm leading to successful token validation.
Actual Result: The issue persists with the same error.

Search on Stack Overflow:
I searched for solutions on Stack Overflow using keywords related to this error, but I did not find a satisfactory answer.
Expected: To find solutions or clues to resolve the token validation issue.
Result: No conclusive answers found.

Questions

1. What can I check or adjust to resolve this error?
2. Are there additional configurations I should include in my Docker or NestJS setup to ensure proper integration with Keycloak?

Thank you for your help!