jupyterlab_galaxahub_motd_extension

Shows the GalaxaHub message of the day in a JupyterLab tab. When the lab starts, the extension pulls the welcome content that the user's groups carry and the broadcasts sent to the user. It opens a Message of the day tab with the hub's entries, or with the local or built-in page when the hub has none.

Features

• Welcome tab on start - opens the Message of the day tab and makes it current when the hub carries at least one welcome entry for the user; notifications alone never open it. The tab carries an orange flag icon before its label
• Once per server start - the tab opens by itself on the first load of the lab after each lab server start; a later load, a browser refresh included, opens no tab, and the palette command opens it at any time
• Local page - when the hub gives no welcome entry for the user (a hub URL setting empty, no motd extension, not reachable, an error, or no entry), the tab shows the local HTML page the lab config names, or, while none is named, the extension's built-in page with its version, what it does, its settings and the hub API it reads
• Silent without a page - with fallback_html naming a file that does not exist, those cases open nothing and log one console line
• Two columns - the entry cards on the left in 3/4 of the width, the Notifications column in the other 1/4; a tab narrower than 800 px stacks them. A lab whose config names no notifications URL has no Notifications column, and its cards take the full width of the tab. The room of the scrollbar beside the cards is kept while they do not scroll, so a card keeps its width
• One card per group - markdown rendered by the lab's own markdown renderer, an HTML package shown in a sandboxed iframe at its hub address, sized to fit its page; the entry's label heads the card, and an entry with no label has no header bar. In a markdown entry a link to a heading of the same entry ([text](#Getting-started) or the GitHub form #getting-started) scrolls to that heading
• Scripts in HTML pages - the JavaScript of an HTML page runs in the tab, in a hub page and in the local page; c.GalaxaHubMotd.html_allow_scripts = False in the lab's Jupyter config stops it
• Notifications catch-up - the broadcasts of the last 24 hours, 3 days or 7 days (a setting) sent to all users and those naming the user, newest first, each a card tinted in its type's colour, with the type's icon, the relative time and an all or direct marker
• Palette command - Message of the day: Open pulls again and reopens the one tab; the tab closes, and the command opens nothing, only when fallback_html names a file that does not exist
• Token stays on the server - a server extension calls the hub with the lab's API token and passes Etags through, so the browser never holds the token and a repeated pull answers 304

Requirements

• JupyterLab >= 4.6
• A GalaxaHub hub carrying galaxahub-motd-extension; without it the tab shows only the local or built-in page
• The two hub URLs in the lab's Jupyter config, as Server configuration states; without them the tab shows only the local or built-in page

Install

pip install jupyterlab_galaxahub_motd_extension

Settings

Server configuration

The lab's Jupyter config names the two hub URLs the extension reads, and optionally a local page, the tab label, whether the tab opens on lab start and whether the scripts of an HTML page run. The two URLs are empty by default, and while either one is empty the extension asks no hub and shows only the local or built-in page.

• Files - jupyter_server_config.py or jupyter_lab_config.py (or their .json form) in a Jupyter config directory; jupyter --paths lists the directories
• Not read - the jupyter_server_config.d/ directories, which carry only extension enabling
• CLI - jupyterlab-galaxahub-motd asks the running lab server for both values, so a --config file on the lab's command line applies to it too
• Token - the extension sends the lab's JUPYTERHUB_API_TOKEN to both URLs, so both must belong to the hub that spawned the lab
• Local page - shown in the same sandboxed frame as a hub HTML page; a path that names no file shows no page, and the server log names it
• Scripts - html_allow_scripts is a lab config setting only, with no entry in the lab's Settings Editor. A page on the lab's origin is read with the user's login, so its script has the access of the lab page itself: it can call the lab server as the user. Keep the setting on only where an administrator alone can write the pages. The frame's sandbox still blocks form submission, alert, confirm and prompt, downloads and navigation of the lab page, without a visible message
• Page height - the tab sets the frame's height to the page's height, so a page whose script sets its height from the window height (window.innerHeight in a resize handler) makes its card grow for as long as the tab is visible; such a page must take its height from its content
• Hub header - a hub can forbid script in its pages with its own Content-Security-Policy header (script-src 'none'); the browser then runs no script in them, whatever this setting says

For a GalaxaHub lab, where JUPYTERHUB_API_URL is the hub API of the lab:

import os

hub = os.environ.get("JUPYTERHUB_API_URL", "")
if hub:
    c.GalaxaHubMotd.motd_api_url = f"{hub}/extensions/motd"
    c.GalaxaHubMotd.notifications_api_url = f"{hub}/user-notifications"
c.GalaxaHubMotd.fallback_html = "/opt/motd/index.html"  # optional; empty shows the built-in page
c.GalaxaHubMotd.label = "Message of the day"            # optional
c.GalaxaHubMotd.open_on_start = True                    # optional; once per lab server start
c.GalaxaHubMotd.html_allow_scripts = True               # optional; False runs no script in a page

Server routes

The server extension proxies three hub reads under its own prefix and adds nothing to them. It reads the two URLs from Server configuration and JUPYTERHUB_API_TOKEN from the lab's environment.

• The hub's status, body, Content-Type, Etag and Cache-Control pass through, and the browser's If-None-Match goes to the hub; a matching Etag answers 304 with no body
• One answer for an absent hub - a hub 404 (no motd extension), a hub that cannot be reached, and an empty URL setting all answer 204 No Content with Cache-Control: no-cache on the terminal and notifications routes; the server log states which of the three it was
• Any other hub status, 403 included, passes through unchanged on those two routes
• Local page - the rich route answers the local page as the one HTML entry whenever the hub gives no entry: every case above, and a 200 with no entry. GET /jupyterlab-galaxahub-motd-extension/local/<path> serves the page fallback_html names and the files in its folder; GET /jupyterlab-galaxahub-motd-extension/about/index.html serves the built-in page with the installed version. Both answer a logged-in user only
• Settings - GET /jupyterlab-galaxahub-motd-extension/settings answers motd_api_url and notifications_api_url as the running server holds them; the CLI reads it
• Hub side - docs/design-api.md states what a hub must answer on the three routes, for a developer who writes the hub side without GalaxaHub

Motd schema

A hub gives the motd through three GET routes at the two URLs of Server configuration. The extension sends Authorization: token <JUPYTERHUB_API_TOKEN>, and the hub answers with the data of the user who owns that token. A hub that answers as this section states works with the extension; docs/design-api.md holds the full contract.

Welcome entries

{
  "entries": [
    {
      "label": "Interns",
      "kind": "markdown",
      "body": "# Welcome\n\nRead the handbook first."
    },
    {
      "label": "Research",
      "kind": "html",
      "url": "/hub/api/extensions/motd/rich/<package-id>/index.html"
    }
  ]
}

• Order - the tab shows one card per entry, in answer order
• No entry - {"entries": []} means the user has no welcome entry, and the tab shows the local or built-in page
• HTML page - the page must allow the lab to frame it (frame-ancestors 'self' when hub and lab share one origin); its scripts run as c.GalaxaHubMotd.html_allow_scripts and the hub's own Content-Security-Policy allow

Broadcasts

{
  "notifications": [
    {
      "ts": "2026-09-29T08:00:00+00:00",
      "message": "Maintenance tonight at 22:00",
      "type": "warning",
      "audience": "all"
    }
  ]
}

Terminal text

GET <motd_api_url>/terminal answers text/plain; charset=utf-8, which the CLI prints as received, and 204 when the user has no terminal text.

Status codes

The hub sends Cache-Control: no-cache on every answer, a 204 included, because a browser caches a 204 by default.

Command line

The package installs jupyterlab-galaxahub-motd, which prints what the hub holds for the user in a lab terminal; it does not print the local or built-in page. It asks the running lab server for the two URLs, so whatever configured the lab applies, and makes the three hub reads itself with JUPYTERHUB_API_TOKEN. It finds the lab server through JUPYTER_SERVER_URL, which JupyterLab sets in every terminal.

jupyterlab-galaxahub-motd show                   # terminal text, rich entries, notifications
jupyterlab-galaxahub-motd notifications --json   # one JSON document
jupyterlab-galaxahub-motd terminal 2>/dev/null   # in a lab startup script

A lab startup script prints the motd with the last line and holds no motd URL and no token. With no motd, or a hub that fails, stdout stays empty.

jupyterlab-galaxahub-motd --help lists the commands, the configuration, the environment variables and the exit codes, and each command's --help carries examples.

The repository carries an agent skill, .agents/skills/jupyterlab-galaxahub-motd-extension/SKILL.md. pip install puts a copy in share/jupyter/agents/skills/ under the Python environment. No agent reads that directory, so a lab image links it into the agent skills directory, with the Python that runs the lab:

mkdir -p ~/.agents/skills
ln -s "$(python -c 'import sys; print(sys.prefix)')/share/jupyter/agents/skills/jupyterlab-galaxahub-motd-extension" ~/.agents/skills/jupyterlab-galaxahub-motd-extension

Agents that read .agents/skills also find it in a clone of this repository; to make it available to Claude Code everywhere, link it into the skills directory from the clone:

ln -s "$PWD/.agents/skills/jupyterlab-galaxahub-motd-extension" ~/.claude/skills/jupyterlab-galaxahub-motd-extension

Uninstall

pip uninstall jupyterlab_galaxahub_motd_extension