workspace directory in a codebase contains the resources that are created/deleted using phi ws up/phi ws down.
Any .py file in the workspace containing a DockerResources, AwsResources or K8sResources object can be used to define the workspace resources.
To add your own resources, just create a python file, define resources and add them to a DockerResources, AwsResources or K8sResources object.
Example
DockerResources
workspace/dev_resources.py
AwsResources
workspace/prd_resources.py