How to access config in the main file of a microservice?

[wayou]

According to the doc, we can access config in main file by:

const configService = app.get(ConfigService);

while this may be not possible for microservice.

async function bootstrap() {
  // how to access config via app before app was created ❓
  // const PORT = app.get(ConfigService).get('PORT');
  const PORT = 4000;
  const app = await NestFactory.createMicroservice<MicroserviceOptions>(
    AppModule,
    {
      transport: Transport.TCP,
      options: {
        port: PORT,
      },
    },
  );
  await app.listen(() => Logger.log(`microservice started on ${PORT}`));
}

[kamilmysliwiec]

Duplicate of #2343