Divide OTB modules in independent repositories

Resume

The goal of this is to separate each modules located in https://gitlab.orfeo-toolbox.org/orfeotoolbox/otb/-/tree/develop/Modules in a separate repo (except Core). A link will be done from otb main repo and each module with the "submodule" git mechanism.

Pro and cons

Separating modules have several advantages:

• Improve CI build time
• Improve unittest jobs and runs as only module related features are tested
• Issues will now be module-related
• Developers only download needed source code

The CI jobs may increase in complexity as we introduce dependencies with modules. Thus we need to trigger modules jobs from core.

Plan

• According to @ytanguy , create a gitlab group to handle all modules in a separate repo. This will be easier for bug tracking and management
• Start with Miscellaneous module, use OTB modules https://www.orfeo-toolbox.org/CookBook-9.0/RemoteModules.html
  • Create external git repo, link it as a submodule
  • OTB core must download corresponding submodule if the cmake -DOTBGroup_Miscellaneous is turned on
  • Compile it separately, you may use OTB core artifact
  • Adapt CI to run corresponding build job and tests
  • Adapt otb CI to start module job when there is a new dependency (i.e. OTB core)
  • Adapt bug tracking for each project ?
  • Add a Readme with compilation help, otb integration, and some exemples
• Repeat for FeatureExtraction
• Repeat for SAR
• Repeat for Segmentation
• Repeat for Hyperspectral
• Repeat for Learning
• Repeat for StereoProcessing