Docker image build proposal

docker-compose/README.md

+# Docker Compose
+
+Documentation on how the LOFAR station control software utilizes docker-compose.
+This documentation is intended for developers listing strategies and their
+respective advantages and disadvantages. In addition, this documentation
+contains developer expectations that they should uphold to.
+
+## Image tagging and change detection
+
+Preventing unnecessary builds of docker images reduces build times and increases
+iteration speed. In order to achieve this the project requires properly tagged
+images and mechanisms for change detection.
+
+For change detection the system relies on git. Git is used to determine the
+directories that have changes between the current and previous commit.
+
+### Types of containers and specific strategies.
+
+- Devices
+- Simulators
+- Base images
+- Services
+
+Devices, are currently bound to the host upon building due to the intrinsics of
+how environment variables are used. They will have to be rebuild and can not be
+pulled from a local registry.
+
+Simulators, Since the source code for simulators is maintained by other teams
+we can not accurately determine from our repository if the simulator has
+changed. Instead, the images should be build by the teams their respective CI
+pipelines. We would simply pull these images.
+
+Base images, these are detected by changes to the .env file in the
+docker-compose directory.
+
+Services, these are detected by changes to the .yml file or directory of the
+respective service inside the docker-compose directory.