I develop an application with nodejs and react. I use dotenv for configuration in my different environment.
I use TFS 2017 for build and release my application.
What is the best practise for add my .env file of production environment?
Production configs can be difficult to maintain. You can use any module or even write your own custom module to load environment variable in to your application.
However, maintaining production .env files locally for each product (i.e. committing them or putting them inside your docker image is a bad idea. If you ever happen to change some of those configs, you will have to manually change in the code for each application, build docker image (if required) and redeploy. If there are just a couple of applications, it might be easy. But if the number of related applications grow in size (as usually happens in case of microservice based architecture) - all of them sharing credentials, ips for database connections etc. it becomes a hectic task to manually change code and redeploy all the applications.
Usually, developers tend to keep a central repository of all credentials and environment variables. For examples, AWS offers parameter store and MS Azure offers Azure Key vault. In such a case, all the parameters are fetched during start time, and all we have to do is restart the application.
So usually people set only one global varibale NODE_ENV (as prod or dev), dynamically fetch all environment variables based on NODE_ENV running something like env $(node read-env-variables.js) node app.js.