How to use environment variables in ClientsModule?

I'm trying to use environment variables in the ClientsModule as such:

import { Module } from '@nestjs/common';
import { ClientsModule, Transport } from '@nestjs/microservices';

@Module({
  imports: [
    TypeOrmModule.forFeature([Process]),
    ClientsModule.register([
      {
        name: 'PROCESS_SERVICE',
        transport: Transport.RMQ,
        options: {
          queue: process.env.RMQ_PRODUCER_QUEUE_NAME,
          urls: [process.env.RMQ_PRODUCER_URL],
          queueOptions: { durable: true },
        },
      },
    ]),

And I've also tried this:

import { Module } from '@nestjs/common';
import { ClientsModule, Transport } from '@nestjs/microservices';
import { ConfigService } from '@nestjs/config';

const configService = new ConfigService();
const rmqProcessUrl = configService.get<string>('RMQ_PRODUCER_URL');
const rmqProcessQueue = configService.get<string>('RMQ_PRODUCER_QUEUE');

@Module({
  imports: [
    TypeOrmModule.forFeature([Process]),
    ClientsModule.register([
      {
        name: 'PROCESSES_SERVICE',
        transport: Transport.RMQ,
        options: {
          queue: rmqProcessQueue,
          urls: [rmqProcessUrl],
          queueOptions: { durable: true },
        },
      },
    ]),

But in both occasions the following error appears:

TypeError: metatype is not a constructor

It works as intended when I use the values directly. I have also tried importing and using

export const rmqServiceName = process.env.RMQ_PRODUCER_QUEUE_NAME

and

export const rmqServiceName = process.env.RMQ_PRODUCER_URL

but that also results in the same error.

So how can I get access to the .env variables in the @ClientsModule? Is there a workaround that I'm missing?

I discovered what is wrong, in case anyone has the same problem as I did.

What should be done is import the nestjs/config and ConfigModule in the app.module.ts and use the async method of ClientsModule.register.

In the app.module.ts

import { Module } from '@nestjs/common';
import { ConfigModule } from '@nestjs/config';

@Module({
  imports: [
    ConfigModule.forRoot({ isGlobal: true }),

In the module I was working on:

import { Module } from '@nestjs/common';
import { ClientsModule, Transport } from '@nestjs/microservices';
import { ConfigModule, ConfigService } from '@nestjs/config';

@Module({
  imports: [
    TypeOrmModule.forFeature([Process]),
    ClientsModule.registerAsync([
      {
        name: 'PROCESSES_SERVICE',
        imports: [ConfigModule],
        useFactory: async (configService: ConfigService) => ({
          transport: Transport.RMQ,
          options: {
            queue: configService.get<string>('RMQ_PRODUCER_QUEUE'),
            urls: [configService.get<string>('RMQ_PRODUCER_URL')],
            queueOptions: { durable: configService.get<boolean>('RMQ_PRODUCER_QUEUE_DURABLE') },
          },
        }),
        inject: [ConfigService],
      },
    ]),