Updating defaults on mybinder.org
This week, we are deploying some updates to repo2docker, the image-building tool that underpins mybinder.org. This may affect your repos. Please get in touch if you have problems! Hopefully this will make things better, more stable, and less surprising overall, but change always breaks something, however hard we work to keep things working.
To highlight the changes:
- Python 3.10 is now the default Python version
- Python 3.11 is now supported, and new versions of Python should be supported more quickly
- If a repo requests an old version of Python (≤ 3.6), it will be installed in a separate environment, as we’ve been doing with Python 2.7 for a long time.
- The server implementation is switched from
jupyter-notebooktojupyter-server
More detail on each change, the reasons behind them, and their consequences below.
Python 3.11 and separate envs for legacy Python support
When building an image, repo2docker installs packages in one or two environments — the kernel environment where your code runs, and the server environment, which runs the Jupyter server. If you’re using a reasonably supported version of Python, these are actually the same environment. This is the vast majority of repositories on mybinder.org. In order to function properly, we have certain requirements of what goes in the ‘server’ environment. Eventually, those requirements start making it difficult to setup the server environment with an outdated version of Python, as packages march ahead with their minimum required Python (The widely adopted NEP 29 suggested dropping Python 3.7 support in December, 2021). Our solution for this has been to separate the kernel environment from the server environment, so they don’t create a conflict. Until recently, only Python 2 was handled this way (most packages dropped Python 2 support years ago). As part of adding support for Python 3.11, we have expanded this behavior to include Python ≤3.6, so if you are using a ‘legacy Python’, currently defined to be Python ≤3.6, your requested packages will be installed in the kernel environment instead of the server environment. This should only have a noticeable effect if you are installing something with server extension components , which includes anything modifying the JupyterLab or notebook interfaces— those will not be available in the server environment. To address this, you will have to upgrade Python or handle the server extension installation in postBuild . PR adding Python 3.11 and adding Python ≤3.6 to legacy Python versions.
Default Python is now 3.10
The default Python for repo2docker and thereby mybinder.org is now Python 3.10, upgraded from 3.7. 3.10 will be used when a repository does not specify which version of Python to use. Following Python’s own annual release cadence, we plan to update this more regularly in the future, lagging behind Python itself by a version or two. This has no effect on your repos if they specify a Python version, which is why we encourage you to specify your Python version! If you don’t, then your Python version will change over time, probably about once a year. PR switching the default Python.
Now launching Jupyter Server
The default UI for mybinder.org has been JupyterLab for some time, with the classic notebook still available if you specify a url of /tree/or /notebooks/mynb.ipynb. When we rolled out that change, we kept the default server as the jupyter-notebook server, for improved compatibility with existing server extensions. As the newer Jupyter Server has taken over, the situation is becoming reversed — using the older notebook server is now the cause of compatibility issues with server extensions, so we are switching the server to launch jupyter-server instead of jupyter-notebook. The classic UI is still available at the same URLs, thanks to nbclassic. This should have no visible effects, as jupyter-server and nbclassic make a great deal of effort to keep classic notebook extensions working, but some extensions may need an update for jupyter-server compatibility if they haven’t been updated already. Because of where the server is specified, there is no supported way for images to express a preference for the deprecated notebook server (PR switching the default server command.
