My directory structure looks like this.

|
|
— Dockerfile
| — .env

Content of .env file looks like this.

VERSION=1.2.0
DATE=2022-05-10

I want to access VERSION and DATE as environment variable both during build time and run time. So ENV is the one I should use. I know that.
How exactly can I do that ?

I tried using RUN command in Dockerfile like

RUN export $(cat .env)

But, it can only be accessed during runtime and not build time.
So, how can this be achieved with ENV ?

P.S. I cannot use docker-compose because the image is going to be used by kubernetes pods, so.