jupyterlab-server-timer

jupyterlab_server_timer

A JupyterLab extension that displays the remaining server run time in the status bar.

This extension is best paired with a spawner such as batchspawner. It allows the user to see when the job running the notebook is going to be terminated.

The extension checks for two environment variables:

• JOB_START_TIME contains a UTC timestamp of the start time of the job. If absent then the time when the notebook becomes ready is used instead. Since it can take a few seconds to start the notebook the time measurement will not be completely accurate in this case and a hard-wired safety margin of 20 seconds will be deduced from the runtime.
• JOB_RUN_TIME contains the number of minutes the server will run. If absent the default is 60.

An modified example batch_script.sh for slurmspawner that sets the variables could look like this:

...
#SBATCH --export=JOB_START_TIME,JOB_RUN_TIME,{{keepvars}}
...
export JOB_START_TIME=$(date +%s)
export JOB_RUN_TIME=90
{{prologue}}
{% if srun %}{{srun}} {% endif %}{{cmd}}
{{epilogue}}

Packages

This extension is composed of a Python package named jupyterlab_server_timer for the server extension and a NPM package named jupyterlab-server-timer for the frontend extension.

Requirements

• JupyterLab >= 4.0.0

Install

To install the extension, execute:

pip install jupyterlab_server_timer

Uninstall

To remove the extension, execute:

pip uninstall jupyterlab_server_timer

Troubleshoot

If you are seeing the frontend extension, but it is not working, check that the server extension is enabled:

jupyter server extension list

If the server extension is installed and enabled, but you are not seeing the frontend extension, check the frontend extension is installed:

jupyter labextension list

Contributing

Development install

Note: You will need NodeJS to build the extension package.

The jlpm command is JupyterLab's pinned version of yarn that is installed with JupyterLab. You may use yarn or npm in lieu of jlpm below.

# Clone the repo to your local environment
# Change directory to the jupyterlab_server_timer directory
# Install package in development mode
pip install -e ".[test]"
# Link your development version of the extension with JupyterLab
jupyter labextension develop . --overwrite
# Server extension must be manually installed in develop mode
jupyter server extension enable jupyterlab_server_timer
# Rebuild extension Typescript source after making changes
jlpm build

You can watch the source directory and run JupyterLab at the same time in different terminals to watch for changes in the extension's source and automatically rebuild the extension.

# Watch the source directory in one terminal, automatically rebuilding when needed
jlpm watch
# Run JupyterLab in another terminal
jupyter lab

With the watch command running, every saved change will immediately be built locally and available in your running JupyterLab. Refresh JupyterLab to load the change in your browser (you may need to wait several seconds for the extension to be rebuilt).

By default, the jlpm build command generates the source maps for this extension to make it easier to debug using the browser dev tools. To also generate source maps for the JupyterLab core extensions, you can run the following command:

jupyter lab build --minimize=False

Development uninstall

# Server extension must be manually disabled in develop mode
jupyter server extension disable jupyterlab_server_timer
pip uninstall jupyterlab_server_timer

In development mode, you will also need to remove the symlink created by jupyter labextension develop command. To find its location, you can run jupyter labextension list to figure out where the labextensions folder is located. Then you can remove the symlink named jupyterlab-server-timer within that folder.

Testing the extension

Server tests

This extension is using Pytest for Python code testing.

Install test dependencies (needed only once):

pip install -e ".[test]"
# Each time you install the Python package, you need to restore the front-end extension link
jupyter labextension develop . --overwrite

To execute them, run:

pytest -vv -r ap --cov jupyterlab_server_timer

Frontend tests

This extension is using Jest for JavaScript code testing.

To execute them, execute:

jlpm
jlpm test

Integration tests

This extension uses Playwright for the integration tests (aka user level tests). More precisely, the JupyterLab helper Galata is used to handle testing the extension in JupyterLab.

More information are provided within the ui-tests README.

Packaging the extension

See RELEASE