Delay SpringBoot application startup until db is up

Question

I have a SpringBoot application that will fail to start up when the database it is using is not up since the datasource bean will fail to initialize. I want for my application to not start before my db is up in order to avoid this failure.

To mention that this app is running in Kubernetes so one option would be to use an init-container. I would want though to have that logic inside the application itself.

First of all, is that a bad idea and I should stick with init-containers?

If it is not a bad idea what is usually the best approach for this. I was looking at Spring Retry and one possible solution seems to be to have retry logic in the @Bean datasource initialization method. Does that have any possible drawbacks? Is there a better way?

Answer 1

Not sure if this works for you but in case you have Data source beans declared.

You can you @Lazy annotation to delay the bean initialization until required.

Your application startup shouldn't fail on startup as the Datasource bean would not be initialized until needed

Answer 2

You can have a startup probe to check DB connections at the start. If you want the DB connections to be constantly pooled for health, you can use other probles. Or in the pipeline which you use to deploy, after the check build unittest phases, you can add a step to check connections of external services/db which you use.