Cronjobs getting called multiple times

I’m submitting a…

[ ] Regression 
[x] Bug report
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

I am using NestJs and trying to use the schedule module for cronjobs. One of the methods is decorated with @Cron('*/30 * * * * * ') and I expected it to run only once after 30 seconds. The issue is after every 30 seconds, the cron runs three times. This is a consistent behavior and happens all the time. However I have observed that other methods which are also cronjobs are working as expected(run only once). Have been trying to figure out the root cause but there is no luck so far.

Expected behavior

The cronjobs should always only run only once.

Minimal reproduction of the problem with instructions

@Cron('*/10 * *  * * *')
  async triggerSessionRemindersCron(): Promise<void> {
    LoggerService.logger.info(`Date:: ${new Date().getTime()}`);
    LoggerService.logger.info('CronjobService::triggerSessionReminders BEGIN');
    // await this.triggerEventsForSessionReminders().catch((e) => {
    //   LoggerService.logger.error(e);
    // });
  }

What is the motivation / use case for changing the behavior?

The current implementation for me results in sending multiple events to webengage which in turn sends multiple notifications to the users.

Environment

Nest version: 7.5.4

 
For Tooling issues:
- Node version: 12.18.2 -->
- Platform:   Mac

Others:
Using npm version 6.14.5

[maxpeterson]

FYI: I found that adding a name fixed my duplicates

  @Cron('*/10 * * * * *')
  async test() {
    this.logger.log('Test unnamed');
  }

  @Cron('*/10 * * * * *', { name: 'test-named' })
  async testNamed() {
    this.logger.log('Test named');
  }

=>

[Nest] 9525   - 13/04/2021, 17:30:39   [NestApplication] Nest application successfully started
[Nest] 9525   - 13/04/2021, 17:30:40   [ScanService] Test unnamed
[Nest] 9525   - 13/04/2021, 17:30:40   [ScanService] Test named
[Nest] 9525   - 13/04/2021, 17:30:40   [ScanService] Test unnamed
[Nest] 9525   - 13/04/2021, 17:30:50   [ScanService] Test named
[Nest] 9525   - 13/04/2021, 17:30:50   [ScanService] Test unnamed
[Nest] 9525   - 13/04/2021, 17:30:50   [ScanService] Test unnamed
[Nest] 9525   - 13/04/2021, 17:31:00   [ScanService] Test unnamed
[Nest] 9525   - 13/04/2021, 17:31:00   [ScanService] Test unnamed
[Nest] 9525   - 13/04/2021, 17:31:00   [ScanService] Test named
[Nest] 9525   - 13/04/2021, 17:31:10   [ScanService] Test unnamed
[Nest] 9525   - 13/04/2021, 17:31:10   [ScanService] Test named
[Nest] 9525   - 13/04/2021, 17:31:10   [ScanService] Test unnamed

The order of the log entries makes it a bit confusing, but if you look at the time stamps you can see it calls Test named once every 10 seconds but Test unnamed twice every 10 seconds

[ronatory]

Also it seems to be that if this is an underlying issue in https://github.com/kelektiv/node-cron then this won’t be fixed quite soon since the project isn’t really maintained anymore. See here https://github.com/kelektiv/node-cron/issues/578