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jupyterlite-pyodide-lock#

Create pre-solved environments for jupyterlite-pyodide-kernel with pyodide-lock.

Installing#

This package is not yet released. See CONTRIBUTING.md for development.
pip install jupyterlite-pyodide-lock
or mamba/conda:
mamba install -c conda-forge jupyterlite-pyodide-lock

Why Use This?#

in the browser
- fetches pyodide-kernel, its dependencies, and configured packages in parallel while pyodide is starting, skpping micropip.install and its requests to the PyPI API
- doesn’t require %pip install for locked packages and their dependencies
  - notebooks and scripts still need to be well-formed, e.g. import my_package
  - once shipped, package versions loaded in the browser won’t change over time
during a build
- doesn’t require rebuilding a full custom pyodide distribution
  - but will patch an custom deployed pyodide
  - all downloaded wheels can be optionally shipped along with the application
- optionally clamp PyPI packages to a known timestamp to ensure newer packages aren’t found during a future solve
- supports multiple sources of custom wheels and dependencies

Feature Comparison#

A number of approaches are available for getting reproducible JupyterLite runtime python environments, either with jupyterlite-pyodide-kernel or other kernels. Choosing one requires some trades of simplicity, reproducibility, flexibility, and performance.

Note

Each tool is evolving, so the tables below should be verified against the different tools when making a decision.

A visitor to a JupyterLite site's needs may be the top priority...

feature	`jupyterlite-pyodide-lock`	`piplite`	jupyterlite-xeus	micropip
needs separate `install` and `import`	no (for locked packages)	yes (`%pip`)	no	no
allows install by PyPI name	yes	yes	no	yes
allows install from URL	yes	yes	no	yes
blocks interaction per package	run cell	run cell	start kernel	run cell
caches in the browser	per package	per package	whole environment	per package

An author of a JupyterLite site may have additional needs...

feature	`jupyterlite-pyodide-lock`	`piplite`	jupyterlite-xeus	pyodide-build
requires “heavy” build dependencies	real browser (and/or `selenium`)	no	minimal, see repo	many, see repo
ships local wheels	yes	yes	maybe?	yes
ships noarch PyPI wheels	yes	yes	yes	yes
ships pyodide emscripten wheels	yes	yes	no	yes
ships arbitrary pyodide zip C libs	no	yes	no	yes
locks multiple versions of same package	no	yes	no	no
optionally clamp to a timestamp	yes	no	no	no

Usage#

Configure#

Requirements#

A number of ways to add requirements to the lock file are supported:

adding wheels in {lite_dir}/static/pyodide-lock
configuring specs as a list of PEP508 dependency specs
configuring packages as a list of
- URLs to remote wheels that will be downloaded and cached
- local paths relative to lite_dir of .whl files (or folders of wheels)

# examples/jupyter_lite_config.json
{ "PyodideLockAddon": { "enabled": true, "specs": [
          # pep508 spec
          "ipywidgets >=8.1,<8.2",
        ], "packages": [
          # a wheel
          "../dist/ipywidgets-8.1.2-py3-none-any.whl",
          # a folder of wheels
          "../dist",
        ] } }

Lockers#

The Locker is responsible for starting a browser, executing micopip.install and micropip.freeze to try to get a viable lock file solution.

{ "PyodideLockAddon": {
      "enabled": true,
      # the default locker: uses naive a `subprocess.Popen` approach
      "locker": "browser",
    }, "BrowserLocker": {
      # requires `firefox` or `firefox.exe` on PATH
      "browser": "firefox",
      "headless": true,
      "private_mode": true,
      "temp_profile": true,
    } }

A convenience CLI options will show some information about detected browsers:

jupyter pyodide-lock browsers

Reproducible Locks#

By configuring the lock date to a UNIX epoch timestamp, artifacts from a PyPI index newer than that date will be filtered out before a lock is attempted.

Combined with a fixed pyodide_url archive, this should prevent known packages and their dependencies from “drifting.”

{
  "PyodideAddon":
    {
      "pyodide_url": f"https://github.com/pyodide/pyodide/releases/download/0.25.0/pyodide-core-0.25.0.tar.bz2",
    },
  "PyodideLockAddon": { "enabled": true, "lock_date_epoch": 1712980201 },
}

Alternately, this can be provided by environemnt variable:

JLPL_LOCK_DATE_EPOCH=$(date -u +%s) jupyter lite build

Getting a lock_date_epoch

As shown in the example above, date can provide this:

date -u +%s

Or python:

>>> from datetime import datetime, timezone
>>> int(datetime.now(tz=timezone.utc).timestamp())

…or git, for the last commit time of a file:

git log -1 --format=%ct requirements.txt

The latter approch, using version control metadata, is recommended, as it shifts the burden of bookkeeping to a verifiable source.