Add healthcheck instructions to example Dockerfile in the documentation

[nikstuckenbrock]

I recently read a recommendation to add the HEALTHCHECK command to a Dockerfile. I was wondering whether it would make sense to include a default /health endpoint in FastAPI and use this for the Docker HEALTHCHECK.
Looking forward for some feedback on this idea.

I found the recommendation in the @bridgecrewio/checkov documentation:

We recommend that you add the HEALTHCHECK instruction to your Docker container images to ensure that health checks are executed against running containers.

An important security control is that of availability. Adding the HEALTHCHECK instruction to your container image ensures that the Docker engine periodically checks the running container instances against that instruction to ensure that containers are still operational.

Based on the results of the health check, the Docker engine could terminate containers which are not responding correctly, and instantiate new ones.

[odiseo0]

It would make sense, yes. You can also use the root endpoint for the healthcheck /

[zoliknemet]

problem with root endpont / is that returns 404 and response body {"detail":"Not Found"}
in this case if you want quick soluction, /docs would be better :)

When I am working on /healthcheck I usually do custom method which for example makes SELECT 1; on database, just to be sure my connections are fine. You can also do other checks on dependencies that you are using.

[nikstuckenbrock]

Thanks for your feedback!
@odiseo0: I like the idea, but I see the same problem as @zoliknemet mentioned.
@zoliknemet: Wouldn't something like a SELECT be the healthcheck for the database container itself so you don't need to check it in the API container?

[zoliknemet]

@nikstuckenbrock yeah it would, but when you are checking SELECT from app part, you also check your database connection pool, not just database itself - database can be up and running, but your app disconnected from it (out of some reason)
It is just a thing I do...

[nikstuckenbrock]

Thanks @zoliknemet!
I think I will create an issue and a PR then to at least include a basic HEALTHCHECK in the docs by default.
I really appreciate your time and help.