Documentation/Labs/ExtensionsServer

This document summarizes the plan to update the infrastructure used to organize the Slicer application and extension packages.

Status

See https://github.com/KitwareMedical/slicer-extensions-webapp/issues

Source code

• Frontend: https://github.com/KitwareMedical/slicer-extensions-webapp/
• Backend: https://github.com/girder/slicer_package_manager
• Provisioning scripts (internal to Kitware): here

Transition Plan

• finalize design and implementation of new extension server (see details below)
• update download.slicer.org to use updated API
• work with sysadmin to setup server instance
• transition data from current system to new system
• update integration with Slicer app

Extension server

Frontend

Requirements:

• source code will be available at https://github.com/KitwareMedical/slicer-extensions-webapp
• display only extensions (it will not replace download.slicer.org)
• use standard web/js library (
• no direct dependency on Girder
• readonly
• leverage the backend API
• deployed using netlify - this will allow anyone in the community  to submit PR and look at preview
• URL will be https://extensions.slicer.org

Preliminary work:

• draft design
• user-feedback)

backend

Requirements:

• leverage the existing work. See https://slicer-package-manager.readthedocs.io/en/latest/user_guide.html
• deployed by Kitware Sysadmin and publicly available as https://slicer-packages.kitware.com
  • Also discussed the possibility of hosting this on Digital Ocean to allow maintenance with community. But this would likely make backup of the database and restoring of the system more complex.
• used to manage both application and extension packages
• extension download stats will be simple download count per Extension per release
• web server logs associated with the backend would be uploaded daily to a private Github project. This would allow the community to generate detailed stats. Similarly to what is done with mhalle/slicer4-download/slicer4-parselogs

Optional:

• ideally Slicer package will be uploaded as GitHub release assets by the build machine and only a URL would be uploaded to Girder. The backend would return a redirect code

Current infrastructure

The current infrastructure is on "life-support":

• the operating system is out-dated, we are working with sysadmin to update it while keeping an older php version (which itself will go end-of-life by the end of the year)
• we are having more and more failed upload because the server require more and more memory.
  • For the past 5 years, we kept increasing the memory. The root cause is a design flow in Midas. See https://github.com/midasplatform/Midas/issues/69
  • Recent changes helped mitigate this. See Slicer/Midas@0d60946
• more and more user are reporting problems with failed upload and download.

Background

During the past two years, we have been working toward phasing out the aging Midas based server used to host, serve and manage Slicer application and extension packages.

• (1) We now have a Girder plugin for the backend (meaning API endpoints and database interaction). See https://slicer-package-manager.readthedocs.io
• (2) We also experimented with few prototype regarding the extension manager but have nothing production ready.

(1) and (2) were done by one of our former intern Pierre Assemat and was funded by the D&A group.