Jakob Kahl and Erico Andrei: Flying from one Plone version to another

This is a talk about migrating from Plone 4 to 6 with the newest toolset.

There are several challenges when doing Plone migrations:

• Highly customized source instances: custom workflow, add-ons, not all of them with versions that worked on Plone 6.
• Complex data structures. For example a Folder with a Link as default page, with pointed to some other content which meanwhile had been moved.
• Migrating Classic UI to Volto
• Also, you might be migrating from a completely different CMS to Plone.

How do we do migrations in Plone in general?

• In place migrations. Run migration steps on the source instance itself. Use the standard upgrade steps from Plone. Suitable for smaller sites with not so much complexity. Especially suitable if you do only a small Plone version update.
• Export - import migrations. You extract data from the source, transform it, and load the structure in the new site. You transform the data outside of the source instance. Suitable for all kinds of migrations. Very safe approach: only once you are sure everything is fine, do you switch over to the newly migrated site. Can be more time consuming.

Let's look at export/import, which has three parts:

• Extraction: you had collective.jsonify, transmogrifier, and now collective.exportimport and plone.exportimport.
• Transformation: transmogrifier, collective.exportimport, and new: collective.transmute.
• Load: Transmogrifier, collective.exportimport, plone.exportimport.

Transmogrifier is old, we won't talk about it now. collective.exportimport: written by Philip Bauer mostly. There is an @@export_all view, and then @@import_all to import it.

collective.transmute is a new tool. This is made to transform data from collective.exportimport to the plone.exportimport format. Potentially it can be used for other migrations as well. Highly customizable and extensible. Tested by pytest. It is standalone software with a nice CLI. No dependency on Plone packages.

Another tool: collective.html2blocks. This is a lightweight Python replacement for the JavaScript Blocks conversion tool. This is extensible and tested.

Lastly plone.exportimport. This is a stripped down version of collective.exportimport. This focuses on extract and load. No transforms. So this is best suited for importing to a Plone site with the same version.

collective.transmute is in alpha, probably a 1.0.0 release in the next weeks. Still missing quite some documentation. Test coverage needs some improvements. You can contribute with PRs, issues, docs.