Dependency injection doesn't work as expected

[vitalnut]

It seems that the method decorated with @SqsMessageHandler() gets called just as plain function, ignoring the class it is defined in and its initialisation steps. My setup is following:

scheduled-jobs.handler.ts

@Injectable()
export class ScheduledJobsHandler {
    private readonly logger = new Logger(ScheduledJobsHandler.name);

    constructor(
        private createInvoicesJob: CreateInvoicesJob,
        private chargeInvoicesJob: ChargeInvoicesJob,
        private squareSyncJob: SquareSyncJob,
    ) {}

    @SqsMessageHandler(SCHEDULED_JOBS_QUEUE_NAME, false)
    async handleMessage(message: AWS.SQS.Message) {
        try {
            this.logger.log(
                `SQS event: ${message.Body},
                 QUEUE NAME: ${SCHEDULED_JOBS_QUEUE_NAME}`,
            );
            const body: any = JSON.parse(message.Body);
            switch (body.jobType) {
                case constants.SCHEDULED_JOBS.CREATE_INVOICES:
                    this.logger.log('Running CREATE INVOICE JOB');
                    await this.createInvoicesJob.createInvoicesForDay(body);
                    this.logger.log('Finished CREATE INVOICE JOB');
                    break;
                case ....
            }
        } catch (e) {
            this.logger.error('An error occurred while processing the message.', e);
        }
    }
}

app.module.ts

@Module({
    imports: [
        ConfigModule.forRoot({ isGlobal: true }),
        ...
        SqsModule.registerAsync({
            inject: [ConfigService],
            useFactory: (config: ConfigService) => ({
                consumers: [
                    {
                        name: config.get('SQS_SCHEDULED_JOBS_QUEUE_NAME'),
                        queueUrl: config.get('SQS_SCHEDULED_JOBS_QUEUE_URL'),
                        region: config.get('AWS_REGION'),
                    },
                ],
            }),
        }),
        MailModule,
    ],
    providers: [ScheduledJobsHandler],
})
export class AppModule {}

When the message is received in the debugger I can see that this.logger and this.createInvoicesJob and even constants are all undefined. Seems like the file itself is not executed, only the decorated function. Is this expected behaviour?

[bryanmaraujo544]

I'm facing exactly the same issue

[RafalKantor]

I think this not work with scope request
@Injectable({ scope: Scope.REQUEST })
When I did poc and replaced my request scoped providers with singleton it worked for me.

[LaurentRos]

Found in this example to inject the dependency using @Inject(forwardRef(() => Service)). Seems to do the job, not sure why we need that though...

[LaurentRos]

Actually forgot the @Injectable() on the Handler in my case...

[nllahat]

any solution for this problem ?

[CaoAnhDev]

I got the same issue. Can anyone help?

[SK-CSE]

regarding above implementation

@SqsMessageHandler(SCHEDULED_JOBS_QUEUE_NAME, false)

SqsMessageHandler have dificulty in taking dynamic name as above, please refer to my solution below

#8 (comment)

[kamran-codora]

@SK-CSE I am using this implementation but getting "Object is possibly undefined" error, although I tried giving it some default value as well. Any workaround for this?