Loading environment variables into Serverless

Storing config in the environment is one of the factors in The Twelve-Factor App. We do not want to store our environment variables in our code. Normally the environment variables is stored in a file called ``.env`` in the root of the application and this file should be added to ``.gitignore`` so that no one can see the values. You may leave a file called ``.env.sample`` to let other team members to know what keys should be included. Each line is composed in ``KEY=VALUE`` format. Blank lines and lines beginning with ``#`` are ignored. Example: ``` AWS_REGION=ap-east-1 ``` In order to load the environment variables so that the Lambda function can run successfully , we need to use ``serverless-dotenv-plugin`` to do so. To install it, simply run ``` npm i -D serverless-dotenv-plugin ``` Then, add the following in your ``serverless.yml`` ``` plugins: - serverless-dotenv-plugin ``` Now you can include your environment variables in your serverless config by referencing them as ``${env:VAR_NAME}``. ``` region: ${env:AWS_REGION} ``` These variables are also injected into lambda functions so that you can reference them as ``process.env.SOMETHING``.