How can I have my instances refresh automatically in Google Cloud Run?

Question

I have a Cloud Run application built in Python and Docker. The application serves a dashboard that runs queries against data and displays visualizations and statistics. Currently, if I want the app to load quickly I have to set the minimum number of instances to a number greater than 0, I typically use 10. This is great for serving the app immediately, however it can become outdated. I would essentially like to be able to keep a minimum number of instances available to serve the app immediately, but I would like it if they would refresh, or shut down and start up, once every few hours or at least once a day. Is there a way to achieve this?

I have tried looking into Cloud Scheduler to somehow get the Cloud Run application to refresh on a schedule, but I was unclear on how to make the whole thing shut down and reload, especially without serving another revision.

Answer 1

I think about a design but I never tested it. Try to do that.

• At startup, store in a global variable the time.Now(). You have the startup time
• Implement a Healthcheck probe. The healthcheck answer OK (HTTP 200) if the NOW minus startup time (the global variable) is below X (1 hour for instance). Else it answer KO (HTTP 500)
• Deploy your Cloud Run service with the new Health check feature

Like that, after X duration, the instance will autodeclare itself unhealthy and Cloud Run will evict it and create a new one.

It should work. Let me know, I'm interested in the result!