Queue.findJobByName

Method Signature

Queue.findJob(predicate, raw)

Parameter: predicate Object or Function

• predicate can be a simple object or a complex function.
• If a function is passed you are restricted to using RethinkDBs ReQL expressions.

Parameter: raw Boolean

• True to return raw database data rather than a Job object

Returns: Array

• An Array of Job objects or an empty Array.
• If you set raw, an Array of generic JavaScript objects.

Example:

q.findJob({ email: '[email protected]' }).then((jobs) => {
  // jobs will either be an empty array
  // or an array of Job objects that have an
  // email property equal to '[email protected]'
}).catch(err => console.error(err))

Description

One of the most flexible methods on the Queue objects is the Queue.findJob. This method exposes the full and rich filter functionality of the RethinkDB ReQL (RethinkDB Query Language).

Using the Queue.findJob method you can extract information about the jobs in the queue. Here is a quick list of information you could obtain using Queue.findJob.

• Confirm a job has not already been added to the queue (ensure unique job).
• Get all jobs related to a common task.
• Get all failed or terminated jobs.
• Produce reports on any job data.

Examples

This example shows how to ensure a job has not already been added to the queue before adding it. You will need some unique identification value assigned to the jobs to be able to find them. In this example there is a Job.hash property however you can use any key/value you like. If it is not a unique property then multiple results will be returned.

Warning: The Queue.findJob is a single atomic operation. It is possible for another Queue object to add the job to the queue in between you finding the job and adding the job.

const Queue = require('rethinkdb-job-queue')
const q = new Queue()

let job = q.createJob({ hash: '12345678' }) // Some know hash value

// findJob will return any job that has job.hash === '12345678'
q.findJob({ hash: '12345678' }).then((exists) => {
  if (exists.length < 1) {
    return q.addJob(job)
  }
  return
}).catch(err => console.error(err))

This example shows how to use a function as the predicate. The function will return all jobs that completed between January 1st, 2012 (included) and January 1st, 2013 (excluded).

const Queue = require('rethinkdb-job-queue')
const q = new Queue()

const predicate = function (job) {
  return job('dateCompleted').during(
    q.r.time(2012, 1, 1, 'Z'), q.r.time(2013, 1, 1, 'Z'))
}

q.findJob(predicate).then((jobs) => {
  // Zero or more jobs in an array.
}).catch(err => console.error(err))

To really understand how powerful this functionality is please read more on the ReQL filter page.