Nest can't resolve dependencies of the searchService (?). Please make sure that the argument at index

Question

I am using Nestjs framework to develop my Elastic Service application. I am using '@nestjs/elasticsearch' library inside my code and i am simply trying to establish database connection and use inside all other module. Please find my code example here.

My App Module looks below

import { AppController } from './app.controller';
import { AppService } from './app.service';
import { ConfigModule } from './config/config.module';
import { DatabaseModule } from './database/database.module';
import { LayoutmgmtModule } from './layoutmgmt/layoutmgmt.module';

@Module({
  imports: [ConfigModule,DatabaseModule, LayoutmgmtModule],
  controllers: [AppController],
  providers: [AppService]  
})
export class AppModule {}

My Database Module is,

import { Module } from '@nestjs/common';
import { ElasticsearchModule } from '@nestjs/elasticsearch';
import {ConfigModule} from '../config/config.module';
import {ConfigService} from '../config/config.service';
import {DatabaseService} from './database.service';

@Module({
  imports:[ElasticsearchModule.registerAsync({      
    imports:[ConfigModule],        
    useFactory: async (configService: ConfigService) => ({
      host: configService.get('ELASTIC_URL'),
      log: 'trace', 
      requestTimeout: 3000     
    }),
    inject:[ConfigService] 
  })],   
  providers:[DatabaseService], 
})
export class DatabaseModule {}

My Database Service is,

import { Injectable,HttpException } from '@nestjs/common';
import { ElasticsearchService } from '@nestjs/elasticsearch';
import { Client } from 'elasticsearch';

@Injectable()
export class DatabaseService {
   private readonly esClient:Client;
    constructor(private readonly elasticsearchService: ElasticsearchService) {
        try {            
            this.esClient = elasticsearchService.getClient();
            this.esClient.ping({ requestTimeout: 3000 },function(err,res,status){
                if (err || !(res)) {
                    console.log('Unable to connect to the server. Please start the server. Error:', err);
                    throw new HttpException({
                        status: 'error',
                        message: 'Unable to connect to the server. Please start the server. Error:'
                     }, 500);                   
                } else {
                    console.log('Connected to Server successfully!',res, status);
                }
            });
        }
        catch(err) { 
                console.log('Error in connection' + err);
                throw new HttpException({
                    status: 'error',
                    message: 'Unable to reach Elasticsearch cluster'
                 }, 500);
        }           
    }  

}

Now Above i had initialized the connection and its getting connected to the database without issues, But i am trying to re-use ElasticsearchService in another module/service called layout module

Layout Module looks below

import { Module } from '@nestjs/common';
import { LayoutmgmtController } from './layoutmgmt.controller';
import { LayoutmgmtService } from './layoutmgmt.service';

@Module({    
  controllers: [LayoutmgmtController],
  providers: [LayoutmgmtService],  
})
export class LayoutmgmtModule {}

Layout Service Looks below

import { Inject, Injectable, Dependencies } from '@nestjs/common';
import { ElasticsearchService } from '@nestjs/elasticsearch';
import { Client } from 'elasticsearch';

@Injectable()
export class LayoutmgmtService {
    private readonly esClient:Client;
    constructor(@Inject(ElasticsearchService) private readonly elasticsearchService: ElasticsearchService) {
        this.esClient = elasticsearchService.getClient();
        if (!this.esClient){
            console.log("Elastic alreayd connected")
        }
    }

}

If i use the ElasticSErachService in above service inside the constructor i am getting the below error, I wanted to reuse the existing connection ..

[Nest] 10724 - 10/14/2019, 4:50:41 PM [ExceptionHandler] Nest can't resolve dependencies of the LayoutmgmtService (?). Please make sure that the argument at index [0] is available in the LayoutmgmtModule context. +40ms Error: Nest can't resolve dependencies of the LayoutmgmtService (?). Please make sure that the argument at index [0] is available in the LayoutmgmtModule context. at Injector.lookupComponentInExports (C:\Subu\Elastic\elastic-nest-js\node_modules@nestjs\core\injector\injector.js:183:19) at process._tickCallback (internal/process/next_tick.js:68:7) at Function.Module.runMain (internal/modules/cjs/loader.js:744:11) at Object. (C:\Subu\Elastic\elastic-nest-js\node_modules\ts-node\src\bin.ts:158:12) at Module._compile (internal/modules/cjs/loader.js:688:30) at Object.Module._extensions..js (internal/modules/cjs/loader.js:699:10) at Module.load (internal/modules/cjs/loader.js:598:32) at tryModuleLoad (internal/modules/cjs/loader.js:537:12) at Function.Module._load (internal/modules/cjs/loader.js:529:3) at Function.Module.runMain (internal/modules/cjs/loader.js:741:12)

Yousef khan Yousef khan · Accepted Answer · 2019-10-15T13:24:39

LayoutmgmtModule and DatabaseModule are not related anyway in your code. You have registered the ElasticsearchModule in DatabaseModule but not in LayoutmgmtModule so it is unable to find the service.

Solution 1

You can get rid of the LayoutmgmtModule by just adding LayoutmgmtController and LayoutmgmtService in DataBaseModule and it should start working

Solution 2

You can make DataBaseModule as global by just adding @Global() before @Module decorator as mentioned here

Nest can't resolve dependencies of the searchService (?). Please make sure that the argument at index

2 Answers