Well, it’s hard to guess what you mean by that, but I’m going to explain how the environment work, and you should be able to infer what you need.
OCL for OpenMRS is deployed as docker image, inside your repository. It’s built as
docker build --force-rm=true --tag=<tag> .
You are free to change this docker image any way you want. But the docker image is shared across all environments (e.g., the same docker image deployed to QA will eventually be deployed to prod).
When the docker container is started, you configured it to start nginx command. You could make it call a bash script and do any preprocessing you wanted.
Check your readme, it explains exactly how to run docker locally.
If you want to give your docker container environment variables that it will manipulate during build time, please create a pull request to your docker-compose file. You should be able to run it locally too.
To sum up, you have full control of your docker image. If you want to pass runtime environment variables, create a pull request and I will deploy.