NestJS RabbitMQ @golevelup/nestjs-rabbitmq Nest 无法解析依赖关系

Question

我正在使用

@golevelup/nestjs-rabbitmq

库构建一个 NestJS 应用程序，以将消息发布到rabbitmq 交换。

我正在 AppModule 中导入并配置 RabbitMQ 模块（这部分似乎工作正常）。

我创建了一个名为 MessagingModule 的模块和一个服务 MessagingService。但是，当我尝试创建 MessagingService 并将 AmqpConnection 对象注入构造函数时，出现错误。

错误：

error:  Nest can't resolve dependencies of the RabbitMQModule (DiscoveryService, ExternalContextCreator, ?, AmqpConnectionManager). Please make sure that the argument RabbitRpcParamsFactory at index [2] is available in the RabbitMQModule context.

Potential solutions:
- Is RabbitMQModule a valid NestJS module?
- If RabbitRpcParamsFactory is a provider, is it part of the current RabbitMQModule?
- If RabbitRpcParamsFactory is exported from a separate @Module, is that module imported within RabbitMQModule?

应用模块

import { ConfigModule } from '@nestjs/config';
import { configuration } from './config/configuration';
import { MessagingModule } from './messaging/messaging.module';
import { RabbitMQModule } from '@golevelup/nestjs-rabbitmq';
import { ConfigService } from '@nestjs/config';

@Module({
  imports: [
    ConfigModule.forRoot({
      isGlobal: true,
      cache: true,
      load: [configuration],
      validationSchema,
      validationOptions: {
        allowUnkown: false,
        abortEarly: true,
      },
    }),
    RabbitMQModule.forRootAsync(RabbitMQModule, {
      imports: [ConfigModule],
      inject: [ConfigService],
      useFactory: async (configService: ConfigService) => ({
        exchanges: [
          {
            name: configService.get<string>('RABBITMQ_EXCHANGE'),
            type: configService.get<string>('RABBITMQ_EXCHANGE_TYPE'),
          },
        ],
        uri: configService.get<string>('RABBITMQ_URL'),
        channels: {
          'channel-1': {
            prefetchCount: 15,
            default: true,
          },
          'channel-2': {
            prefetchCount: 2,
          },
        },
        connectionInitOptions: { wait: false },
        enableControllerDiscovery: true,
      }),
    }),
    MessagingModule,
  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

消息模块

import { RabbitMQModule } from '@golevelup/nestjs-rabbitmq';
import { Module } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { MessagingService } from './messaging.service';
import { MessagingController } from './messaging.controller';

@Module({
  
  imports: [
    RabbitMQModule,
    MessagingModule,
  ],
  providers: [ConfigService, MessagingService],
  controllers: [MessagingController],
  exports: [MessagingService],
})
export class MessagingModule {}

消息服务

import { Injectable } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { AmqpConnection } from '@golevelup/nestjs-rabbitmq';

@Injectable()
export class MessagingService {
  constructor(private readonly amqpConnection: AmqpConnection) {}

  // Publish the event to the exchange
  public async publish<T>(exchange: string, event: T): Promise<void> {
    await this.amqpConnection.publish(exchange, '', event);
  }

}

Answer 1

每次要使用

RabbitMQModule

时，都需要使用

forRoot

/

forRootAsync

方法来确保设置模块所需的所有提供程序。如果您只想调用一次，您可以为其设置一个包装器模块，如下所示：

@Module({
  imports: [
    RabbitMQModule.forRootAsync(RabbitMQModule, {
      imports: [ConfigModule],
      inject: [ConfigService],
      useFactory: async (configService: ConfigService) => ({
        exchanges: [
          {
            name: configService.get<string>('RABBITMQ_EXCHANGE'),
            type: configService.get<string>('RABBITMQ_EXCHANGE_TYPE'),
          },
        ],
        uri: configService.get<string>('RABBITMQ_URL'),
        channels: {
          'channel-1': {
            prefetchCount: 15,
            default: true,
          },
          'channel-2': {
            prefetchCount: 2,
          },
        },
        connectionInitOptions: { wait: false },
        enableControllerDiscovery: true,
      }),
    }),
  ],
  exports: [RabbitMQModule],
})
export class RabbitModule {}

现在您可以添加

RabbitModule

而不是

RabbitMQModule

，每次都会获得与预先配置相同的

RabbitMQModule

。