AlreadyHasActiveConnectionError: Cannot create a new connection named "default", because connection with such name already exist and it now has an active connection session

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[ x ] Bug report
[ ] Feature request
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Current behavior

I am getting this issue while trying to use the application context for my job queues. While NestFactory.createApplicationContext(AppModule) is initialising the application module TypeOrm is creating connection with same default name. How do I prevent it?

[Nest] 11985   - 2019-1-16 16:08:34   [TypeOrmModule] Unable to connect to the database. Retrying (1)... +31ms
AlreadyHasActiveConnectionError: Cannot create a new connection named "default", because connection with such name already exist and it now has an active connection session.
    at new AlreadyHasActiveConnectionError (/var/www/sxapi/src/error/AlreadyHasActiveConnectionError.ts:8:9)
    at ConnectionManager.create (/var/www/sxapi/src/connection/ConnectionManager.ts:57:23)
    at Object.<anonymous> (/var/www/sxapi/src/index.ts:219:35)
    at step (/var/www/sxapi/node_modules/typeorm/index.js:32:23)
    at Object.next (/var/www/sxapi/node_modules/typeorm/index.js:13:53)
    at /var/www/sxapi/node_modules/typeorm/index.js:7:71
    at new Promise (<anonymous>)
    at __awaiter (/var/www/sxapi/node_modules/typeorm/index.js:3:12)
    at Object.createConnection (/var/www/sxapi/node_modules/typeorm/index.js:215:12)
    at rxjs_1.defer (/var/www/sxapi/node_modules/@nestjs/typeorm/dist/typeorm-core.module.js:137:29)
    at Observable._subscribe (/var/www/sxapi/node_modules/rxjs/src/internal/observable/defer.ts:57:15)
    at Observable._trySubscribe (/var/www/sxapi/node_modules/rxjs/src/internal/Observable.ts:224:19)
    at Observable.subscribe (/var/www/sxapi/node_modules/rxjs/src/internal/Observable.ts:205:14)
    at RetryWhenOperator.call (/var/www/sxapi/node_modules/rxjs/src/internal/operators/retryWhen.ts:39:19)
    at Observable.subscribe (/var/www/sxapi/node_modules/rxjs/src/internal/Observable.ts:200:16)
    at /var/www/sxapi/node_modules/rxjs/src/internal/Observable.ts:345:12

My Job Processor:

const VisitorCheckinNotificationProcessor = async (
  job: Job,
  done: DoneCallback,
) => {
  // application context
  const context = await NestFactory.createApplicationContext(AppModule);
  let data: any = job.data;

  console.log('[VISITOR_CHECKIN_NOTIFICATION_SENT]', data);

  try {
    await context.close();
  } catch (e) {
    console.log('[EXCEPTION WHILE TERMINATING APPLICATION CONTEXT]', e);
  }

  done(null, data);
};

app.module.ts

@Module({
  imports: [
    TypeOrmModule.forRootAsync({
      useFactory: (config: ConfigService) => ({
        type: 'mysql',
        host: config.mysqlHost,
        port: config.mysqlPort,
        username: config.mysqlUsername,
        password: config.mysqlPassword,
        database: config.databaseName,
        entities: [__dirname + '/**/*.entity{.ts,.js}'],
        synchronize: config.databaseSyncEnabled,
        logging: config.databaseLoggingEnabled,
      }),
      inject: [ConfigService],
    }),
    CoreModule,
    UserModule,
  ],
  controllers: [AppController],
})
export class AppModule {}

Environment

Nest version: 5.4.0

 
For Tooling issues:
- Node version: 9.4  
- Platform:  Linux (Ubuntu 18.04) 

[kamilmysliwiec]

Set keepConnectionAlive option to true in the TypeOrmModule options.

[iamsayantan]

@kamilmysliwiec, Yep it solves the issue. Could you please explain what happens?