Bull: How to check for worker health.

[lan-nguyen91]

Question: Worker HealthCheck

I have a simple implementation where API create jobs, and multiple workers just subscribe and process jobs.

I would like to scale the workers and monitor their health. Worker is just a simple script file and doesn't have any rest endpoint.
What would be the best way to get the health of the worker. Ideally worker will be running in a separate container which has no knowledge of the main API.

Is Bull provide such functionality, if not is it prefer if I just open another queue for healthcheck (sound like a hack) 🤔

Thanks.

[manast]

There is no health check built in. What we have is a getter that returns all the workers for a given queue https://github.com/OptimalBits/bull/blob/master/lib/worker.js#L18
I am afraid is not yet documented.

[hymloth]

It would be great if there was a way to have health check built in. My use case is that I run sandboxed workers on AWS Fargate, which after some hours seem like zombies (they seem to be up & running but they do not consume tasks). Why this happens is beyond the scope of this thread (perhaps a memory leak, a terrible bug etc) but if there was a health check functionality I could easily spot zombies and kill the corresponding tasks (and spawn new ones).

[manast]

@hymloth I will think about it. Although I cannot figure out an easy way to do it, maybe we could put the worker ID on every processed job and by examining the last N jobs we can see if there are workers that have not been processing any jobs and be reported as candidates for being Zombies or something like that.

[fmoessle]

Would be great to have a method to check if the queue still has an open connection to the database.

[joelrozen]

I am wanting the same as @fmoessle above. Just a bull method that returns the existing Redis.status. My use case is checking all my services are up. I can set a new connection to redis of course that tells me Redis is running, but doesn't necessarily tell me if Bull is still connected or not.

[manast]

You can use the "getWorkers" api to get all the current online workers that are connected to the redis instance.