Agenda: Attempting to run `agenda.cancel()` throws error

[niftylettuce]

Per the current code here https://github.com/rschmukler/agenda/blob/a5b8a89df4d5bf4d7c667fa4a2559da8526da0df/lib/agenda.js#L318

Agenda.prototype.cancel = function(query, cb) {
  this._collection.deleteMany( query, function( error, result ){
    if (cb) {
      cb( error, result && result.result ? result.result.n : undefined );
    }
  });
};

We should probably implement a safety check to ensure that this._collection is defined as well as this._collection.deleteMany. Unless there is a better option here?

[fabong]

Hi, a simple way to produce the error is to start with a database with no collection, you will get this error: TypeError: Cannot read property 'deleteMany' of undefined. I want to do this to ensure in my tests that there is no saved job before I run them. I can make a pull-request for it if you want.

[simison]

@fabong PRs are always welcome!

[dcsan]

I also get this error when running cancel at startup.

Cannot read property 'deleteMany' of undefined

[dcsan]

the code is something like this (TS)

// tasks
import Logger from "../../../utils/Logger"
const logger = new Logger('Tasks')
import Project from '../models/Project'
import Agenda = require('agenda')
const mongoUri = process.env.MONGODB_URI || "mongodb://127.0.0.1:27017/test_database"

const TaskConfig = {
  processInterval: '1 minutes',
  scrapeInterval: '2 minutes'
}

const Tasks = {

  async init() {

    const agenda = new Agenda({
      db: {
        address: mongoUri,
        collection: 'agendaTasks',
        options: { useNewUrlParser: true }
      },
      processEvery: TaskConfig.processInterval
    })

    await agenda.cancel({}) // remove all jobs
    // await agenda.purge()    // remove not defined jobs

    agenda.define('sayHello', job => {
      logger.log('Hello!', job)
    })

    agenda.define('scrapeAll', async (job) => {
      logger.log('run scrapeAll', job)
      const opts = { start: 'now' }
      const res = await Project.scrapeAll()
      logger.log('scrapeAll result => ', res)
      // Project.scrapeAll((result: any) => {
      //   logger.log('agenda scrapeAll done. result:', result)
      // })
      // done()
    })

    await agenda.start()

    await agenda.every(TaskConfig.scrapeInterval, 'scrapeAll')
    // await agenda.every('10 seconds', 'sayHello')

    logger.log('agenda init done')

  }

}

export default Tasks


// (async function () {
//   // IIFE to give access to async/await
//   await agenda.start();

//   await agenda.every('3 minutes', 'delete old users');

//   // Alternatively, you could also do:
//   await agenda.every('*/3 * * * *', 'delete old users');
// })()

  agenda:cancel attempting to cancel all Agenda jobs {} +0ms
unhandledRejection => TypeError: Cannot read property 'deleteMany' of undefined
    at Agenda.module.exports [as cancel] (/Users/dc/dev/tix/recobot/stack/backend/node_modules/agenda/lib/agenda/cancel.js:14:27)
    at Object.<anonymous> (/Users/dc/dev/tix/recobot/stack/backend/server.js:4135:26)

[dcsan]

is new Agenda actually async until it has a connection?

[dcsan]

well this seems to work

    await agenda.start()
    await agenda.cancel({}) // remove all jobs
    await agenda.every(TaskConfig.scrapeInterval, 'scrapeAll', {})