jupyterlab-module-federation

This repository is a temporary playground for implementing a new JupyterLab extension system that utilizes the Module Federation capabilities in WebPack 5.

We will be making PRs to jupyterlab_server and jupyterlab once this work is stable.

See https://github.com/jupyterlab/jupyterlab/issues/7468 for full background and discussion.

Installation

Prereqs: python 3.5+ and nodejs

To build:

bash install.sh

To run:

python main.py

Goals

• Users should be able to install and use extensions without requiring node or a build step
• Extension authors should be able to easily build and distribute extensions
• The existing capabilities of bundling extensions should still work
• Administrators should regain the ability to set global configuration and packages where possible
• Dynamic extensions should layer on top of existing extensions similar to how pip install --user works
• Extensions should be discoverable

Implementation

• We add a labextensions build Python script that is used to build bundles
  • The command produces a set of static assets that are shipped along with a package (notionally on pip/conda)
  • It needs to be a Python cli so it can use the dependency metadata from the active JupyterLab
  • The assets include a module federation remoteEntry.js, generated bundles, and some other files that we use
    • package.orig.json is the original package.json file that we use to gather metadata about the package
    • build_log.json has all of the webpack options used to build the extension, for debugging purposes
    • we use the existing @jupyterlab/buildutils -> build to generate the imports.css, schemas and themes file structure
• We add a schema for the valid jupyterlab metadata for an extension's package.json describing the available options
• We add a labextensions handler in jupyterlab_server that loads static assets from labextensions paths, following a similar logic to how nbextensions are discovered and loaded from disk
• We augment the settings and themes handlers in jupyterlab_server to load from the new labextensions locations, favoring the dynamic extension locations over the bundled ones
• We add a labextension develop command used to install an in-development extension into JupyterLab. The default behavior is to create a symlink in the sys-prefix/share/jupyter/labextensions/package-name to the static directory of the extension
• We provide a cookiecutter that handles all of the scaffolding for an extension author, including the shipping of data_files so that when the user installs the package, the static assets end up in share/jupyter/labextensions
• We handle disabling of lab extensions using a trait on the LabApp class, so it can be set by admins and overridden by users. Extensions are automatically enabled when installed, and must be explicitly disabled. The disabled config can consist of a package name or a plugin regex pattern
• Extensions can provide disabled metadata that can be used to replace an entire extension or individual plugins
• page_config and overrides are also handled with traits so that admins can provide defaults and users can provide overrides
• We will update the extension-manager to target metadata on pypi/conda and consume those packages.

Tools

• jupyter labexension build python command line tool
• jupyter labextension develop python command line tool
• cookiecutter for extension authors

Workflow for extension authors

• Use the cookiecutter to create the extension
• Run jupyter labextension develop to build and symlink the files
• Run jupyter labextension watch to start watching
• Run jupyter lab
• Make changes to source
• Refresh the application page
• When finished, publish the package to pypi/conda