It’s a good practice to avoid storing any sensitive values in environment variables. So, my business partner Iskandre and I have integrated secrets usage in all our applications. The best way to do it in GCP is by using Secret Manager. Here you can read how to add an access to Secret Manager for your GKE deployment, so you can use secrets in a manifest.

Then you need to add an integration to your application.

Here on Iskandre website you can read a tutorial how to add Python Secret Manager to Alpine Linux containers