Running background processes in Google Cloud Run

user_3080315 0
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I have a lightweight server that runs cron jobs at a given time. As I understand Google Cloud Run only processes incoming requests and then becomes idle after a short time if there is no other request to process. Hence, it is not advisable to deploy that cron service to Cloud Run.

Out of curiosity, I deployed the following server that starts up and then prints a log every hour.

const express = require('express');
const app = express();

setInterval(() => console.log('ping!'), 1000 * 60 * 60);

app.listen(process.env.PORT, () => {
  console.log('server listening');
})

I deployed it with a minimum and maximum instance count of 1. It has not received any request and when I checked back the next day, it was precisely printing the log every hour. Was this coincidence or can I use this setup for production?

google-cloud-run google-cloud-platform
2 Answers

If you set the min instance to 1 and the CPU always on to true, yes, you can perform background compute intensive processing without CPU Throttling (in your hello world case, you can use the few CPU % allowed to the idle instance without the CPU always on option).

BUT, and the but is very important, you will pay for 1 Cloud Run instance always up. In addition, is you receive request, you can scale up and have more than 1 instance up and running. Does it make sense to have several instances with the same CRON scheduling? (except if you set the max instance to 1).

At the end, the best pattern is to host the scheduling outside, on Cloud Scheduler, and then to query your instance to perform the task. It's serverless, you can handle several task in parallel, it's scalable.

user_113725930

From my understanding no.

From the documentation here, Google indicates that the CPU of idle instances is throttled to nearly zero. I suppose this means that very simple operation can still be performed (e.g. logging a string every hour). I guess you could test it more extensively by doing some more complex operations and evaluate the processing time of these operations.

Either way, I would not count on it in a production environment. There is no guarantee that the CPU "throttled to nearly zero" will be able to complete the operations you need in a reasonable time delay.

user_142481160
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