Managing R support in main and deployments when the R runtime is installed separately

[zyratlo]

R UDFs run through texera-rudf, a package installed separately because it depends on rpy2 (GPLv2), which is not compatible with the Apache license (see #4155). The rest of R support still lives in main, and each piece is handled on its own. I ran into this while adding R to the notebook migration tool (#8009) and wanted to raise it.

R in main today

• RUDF and RUDFSource operators, listed under an R group in the operator menu
• r.path in udf.conf, passed to Python workers as R_HOME
• R mode in the code editor
• An R UDF guide in the agent service prompt
• Example R UDFs in pytexera
• Soon, an R option in the migration tool (feat(notebook-migration): add r prompts and build rudf operators for r sources #8911, feat(notebook-migration): add r notebooks to the import modal #8912)

How each part offers or restricts R

Every part makes its own decision, and none of them knows whether texera-rudf is installed:

• Operator menu: always shows the R group.
• Agent service: adds the R UDF guide to an agent's system prompt unless that agent's allowed operator list is set and leaves out RUDF. An empty list means all operators, so by default every agent is taught to write R UDFs.
• Code editor: always opens R operators in R mode.
• Migration tool: will have its own flag, rNotebookMigrationEnabled, default off.
• Execution: the Python worker imports texera-rudf only when an R operator runs. If it is missing, the run fails with an install hint.

So a user can be offered R by the menu or the agent, build a whole workflow, and only learn at execution time that R is not available. None of our images install texera-rudf, so out of the box no deployment can run R.

Questions

1. Should one R setting control all of this, hiding the operators, the agent guide and the migration option together?
2. Should it be a config flag, or detected from whether texera-rudf is installed?
3. Should there be an image option that installs R and texera-rudf?
4. How can we streamline managing these types of situations for active deployments?