node.jsredisqueuebull

Ability to provide insights from Redis Bull Queue data

I have an application that makes API calls to another system, and it queues these API calls in a queue using Bull and Redis.

However, occasionally it gets bogged down with lots of API calls, or something stops working properly, and I want an easy way for users to check if the system is just "busy". (Otherwise, if they perform some action, and 10 minutes later it hasn't completed, they'll keep trying it again, and then we get a backlog of more entries (and in some cases data issues where they've issued duplicate parts, etc.)

Here's what a single "key" looks like for a successful API call in the queue:

HSET "bull:webApi:4822" "timestamp" "1639085540683"
HSET "bull:webApi:4822" "returnvalue" "{"id":"e1df8bb4-fb6c-41ad-ba62-774fe64b7882","workOrderNumber":"WO309967","status":"success"}"
HSET "bull:webApi:4822" "processedOn" "1639085623027"
HSET "bull:webApi:4822" "data" "{"id":"e1df8bb4-fb6c-41ad-ba62-774fe64b7882","token":"eyJ0eXAiOiJKV1QiL....dQVyEpXt64Fznudfg","workOrder":{"members":{"lShopFloorLoad":true,"origStartDate":"2021-12-09T00:00:00","origRequiredQty":2,"requiredQty":2,"requiredDate":"2021-12-09T00:00:00","origRequiredDate":"2021-12-09T00:00:00","statusCode":"Released","imaItemName":"Solid Pin - Black","startDate":"2021-12-09T00:00:00","reference":"HS790022053","itemId":"13840402"}},"socketId":"3b9gejTZjAXsnEITAAvB","type":"Create WO"}"
HSET "bull:webApi:4822" "delay" "0"
HSET "bull:webApi:4822" "priority" "0"
HSET "bull:webApi:4822" "name" "__default__"
HSET "bull:webApi:4822" "opts" "{"lifo":true,"attempts":1,"delay":0,"timestamp":1639085540683}"
HSET "bull:webApi:4822" "finishedOn" "1639085623934"

You can see in this case it took 83 seconds to process. (1639085540 - 1639085623)

I'd like to be able to provide summary metrics like:

I'd also like to be able to provide a list of the 50 most recent API calls, formatted in a nice way and tagged with "success", "pending", or "failed".

I'm fairly new to Redis and Bull, and I'm trying to figure out how to query this data (using Redis in Node.js) and return this data as JSON to the application.

I can pull a list of keys like this:

// @route   GET /status
async function status(req, res) {
  const client = createClient({
    url: `redis://${REDIS_SERVER}:6379`
  });
  try {
      client.on('error', (err) => console.log('Redis Client Error', err));
      await client.connect();
      const value = await client.keys('*');
      res.json(value)

  } catch (error) {
      console.log('ERROR getting status: ', error.message, new Date())
      res.status(500).json({ message: error.message })
  } finally {
    client.quit()
  }
}

Which will return ["bull:webApi:3","bull:webApi:1","bull:webApi:2"...]

But how can I pull the values associated to the respective keys?

And how can I find the key with the highest number, and then pull the details for the "last 50". In SQL, it would be like doing a ORDER BY key_number DESC LIMIT 50 - but I'm not sure how to do it in Redis.

Solution

  • I'm a bit late here, but if you're not set on manually digging around in Redis, I think Bull's API, in particular Queue#getJobs(), has everything you need here, and should be much easier to work with. Generally, you shouldn't have to reach into Redis to do any common tasks like this, that's what Bull is for!

    If I understand you goal correctly, you should be able to do something like:

    const Queue = require('bull')

async function status (req, res) {
  const { listNum = 10 } = req.params
  const api_queue = new Queue('webApi', `redis://${REDIS_SERVER}:6379`)
  const current_timestamp_sec = new Date().getTime() / 1000 // convert to seconds

  const recent_jobs = await api_queue.getJobs(null, 0, listNum)
  const results = recent_jobs.map(job => {
    const processed_on_sec = job.processedOn / 1000
    const finished_on_sec = job.finishedOn / 1000
    return {
      request_data: job.data,
      return_data: job.returnvalue,
      processedOn: processed_on_sec,
      finishedOn: finished_on_sec,
      duration: finished_on_sec - processed_on_sec,
      elapsedSinceStart: current_timestamp_sec - processed_on_sec,
      elapsedSinceFinished: current_timestamp_sec - finished_on_sec
    }
  })
  res.json(results)
}

    That will get you the most recent numList* jobs in your queue. I haven't tested this full code, and I'll leave the error handling and adding of your custom fields to the job data up to you, but the core of it is solid and I think that should meet your needs without ever having to think about how Bull stores things in Redis.

    I also included a suggestion on how to deal with timestamps a bit more nicely, you don't need to do string processing to convert milliseconds to seconds. If you need them to be integers you can wrap them in Math.floor().

    * at least that many, anyway - see the second note below

    A couple notes: