jupyterhub: Bring the role to a working state

jupyterhub/README.md

-WIP JupyterHUB role
-===================
+JupyterHub deployment to learn programming with JS
+==================================================
 
-**Work in progress, cannot be used as-is.**
+- Deploy JupyterHub
+- Deploy IJavasScript kernel to allow JS notebooks
+- Tweak IJavaScript config to add `prompt()` and `alert()` synchronous
+  functions
+- Set up a locale (translation)
+
+*see also: jupyter*
+
+## Security warning
+
+Be conscious that JupyterHub gives a remote (unprivilleged) shell access to
+logged-in users, and that this implementation is not using docker isolation.
+
+## Performance warning
+
+JupyterHub can be quite intensive on resources, by experience, a group of 10
+people toying with a few notebooks will quickly require 2G RAM dedicated to
+Jupyter. If you experience killed notebooks or notebooks refusing to start as
+more users connect, you should give a look at RAM usage and consider adding
+more.
+
+Variables
+---------
+
+### Optional (interface language)
+
+Use both or use none, note that you have to use one of
+jupyter
+[supported languages](https://github.com/JocelynDelalande/notebook/blob/jd-french-i18n/notebook/i18n/nbjs.json#L3-L6). Left
+those settings unchanged to use plain old English.
+
+- *jupyterhub_locale* : a unix locale (ex: `fr_FR`)
+- *jupyterhub_system_locale* : a unix locale with charset indication (ex: `fr_FR.utf8`)

jupyterhub/tasks/ijavascript.yml

@@ -3,5 +3,18 @@
 # Not that it seems not required for Debian stretch
 - name: Install npm deps
   npm:
-    name: ijavascript
+    name: "{{ item }}"
     global: yes
+  with_items:
+    - ijavascript
+    - fibers # for synchronous functions
+
+- name: Install ijavascript kernel for notebooks
+  shell: "ijsinstall --install=global --startup-script=/opt/jupyterhub/js-startup.js"
+  environment:
+    PATH: "/opt/jupyterhub/venv/bin:{{ ansible_env.PATH }}"
+
+- name: Deploy custom startup script (with custom sync functions for learning)
+  template:
+    src: js-startup.js
+    dest: /opt/jupyterhub/js-startup.js
\ No newline at end of file

jupyterhub/tasks/main.yml

-# This first task is actually required by ijavascript
-# to get a recent version of node (jessie-backports contains one, but with no
-# npm…)
-# Seems un-needed on strecth (but not tested)
-- name: Install node from nodesource as ijs wont run with node 0.10x
+# This first task is actually required by ijavascript to get a recent version
+# of node (jessie-backports and stretch contains a recent one, but lacking npm)
+#
+- name: Install node from nodesource
   import_tasks: nodesource.yml
 
 - name: install apt dependencies
@@ -35,6 +34,9 @@
   become: jupyterhub
   notify: restart jupyterhub
 
+- name: install jupyter notebook (with french translation)
+  include: notebook.yml
+
 - name: Install npm deps
   npm:
     name: configurable-http-proxy
@@ -78,6 +80,9 @@
     dest: /etc/jupyterhub/jupyterhub_config.py
   notify: restart jupyterhub
 
+- name: Install ijavascript notebook kernel
+  import_tasks: ijavascript.yml
+
 - name: systemd script is in place
   template:
     src: jupyterhub.service.j2
@@ -89,5 +94,3 @@
 - name: jupyterhub is started
   service: name=jupyterhub state=started
 
-- name: Install ijavascript notebook kernel
-  import_tasks: ijavascript.yml

jupyterhub/tasks/notebook.yml

+- name: Install jupyter notebook
+  pip:
+    # Could switch to stable release once PR is merged
+    # https://github.com/jupyter/notebook/pull/3888
+    name: "git+https://github.com/JocelynDelalande/notebook.git@jd-french-i18n#egg=notebook"
+    virtualenv: /opt/jupyterhub/venv
+  become: jupyterhub
+  notify: restart jupyterhub
+  register: updated_notebook
+
+- name: Install pybabel
+  # Could drop this step once issue is fixed
+  # https://github.com/jupyter/notebook/issues/3102
+  pip:
+    name: babel
+    virtualenv: /opt/jupyterhub/venv
+  become: jupyterhub
+  when: jupyterhub_locale
+
+- name: Install po2json
+  # A recent version is required for -p option
+  # Could drop this step once issue is fixed
+  # https://github.com/jupyter/notebook/issues/3102
+  npm:
+    name: po2json
+    global: yes
+  when: jupyterhub_locale
+
+- name: Get i18n path
+  # Could drop this step once issue is fixed
+  # https://github.com/jupyter/notebook/issues/3102
+  command: "/opt/jupyterhub/venv/bin/python -c 'import notebook.i18n;print(notebook.i18n.__path__[0])'"
+  register: i18n_path
+  when: jupyterhub_locale
+
+- name: Compile translations (.po → .mo)
+  # Could drop this step once issue is fixed
+  # https://github.com/jupyter/notebook/issues/3102
+  command: "/opt/jupyterhub/venv/bin/pybabel compile -D notebook -f -l {{ jupyterhub_locale }} -i {{ jupyterhub_locale }}/LC_MESSAGES/{{ item }}.po -o {{ jupyterhub_locale }}/LC_MESSAGES/{{ item }}.mo"
+  args:
+    chdir: "{{ i18n_path.stdout }}"
+  with_items:
+    - notebook
+    - nbui
+  when: updated_notebook.changed and jupyterhub_locale
+  notify: restart jupyterhub
+  become: jupyterhub
+
+- name: Compile translations (.po → .json)
+  # Could drop this step once issue is fixed
+  # https://github.com/jupyter/notebook/issues/3102
+  command: "po2json -p -F -f jed1.x -d nbjs {{ jupyterhub_locale }}/LC_MESSAGES/nbjs.po {{ jupyterhub_locale }}/LC_MESSAGES/nbjs.json"
+  args:
+    chdir: "{{ i18n_path.stdout }}"
+  when: updated_notebook.changed and jupyterhub_locale
+  notify: restart jupyterhub
+  become: jupyterhub

jupyterhub/templates/js-startup.js

+// {{ ansible_managed }}
+
+/*
+ * Custom startup script to ease programming learning with ijavascript notebooks :
+ *
+ * - Wrap every cell execution with Fiber
+ * - Offer the following non-standard JavaScript functions
+ *   - alert(<msg>) : alias to console.log
+ *   - prompt(<msg>) : browser-like, synchronous
+ *   - afficheLigne(<nbTirets>) : draws a line on screen
+ *
+ * /!\ That startup script prevents global scope from being shared among cells /!\
+ *
+ */
+var Fiber = require('fibers');
+
+global.alert = function (msg) {
+  console.log(msg);
+};
+
+/* Wrap every execution into fiber environment
+*
+* To allow synchronous magic happen
+*/
+var runInThisContext = vm.runInThisContext;
+
+vm.runInThisContext = function(code) {
+    runInThisContext("Fiber(function() {" + code + "}).run();");
+};
+
+/** Synchronous sleep-like function for JavaScript
+ *
+ * Used to implement busy loops (ugly for performance, but sometimes, that is
+ * not what most matters).
+ */
+function fiberSleep(ms) {
+	var fiber = Fiber.current;
+	setTimeout(function() {
+		fiber.run();
+	}, ms);
+	Fiber.yield();
+}
+
+/** Synchronously prompts the user for a string
+ *
+ * Similar to the prompt() function on browsers. Returns the typed value.
+ */
+global.prompt = function(msg) {
+  var ret;
+  var ready = false;
+  $$.input({prompt: msg+ ' ', password: false}, function(err, msg) {
+    ret = msg;
+    ready = true;
+    $$.done();
+  });
+  while (!ready) {
+    fiberSleep(100);
+  }
+  return ret;
+};
+
+
+global.afficheLigne = function(nbTirets) {
+  var l = '';
+  for (var i=0; i < nbTirets; i++) {
+    l += '-';
+  }
+  alert(l);
+};

jupyterhub/templates/jupyterhub_config.py.j2

@@ -3,7 +3,7 @@
 
 ### GLOBAL ###
 
-## Avoid listening on iternet (we have a nginx for that)
+## Avoid listening on Internet (we have a nginx for that)
 c.JupyterHub.ip = '127.0.0.1'
 
 
@@ -13,14 +13,20 @@ c.JupyterHub.admin_access = True
 
 ### SPAWNER ###
 
-## Use our in-venv sudospawner
+## Specific spawner config (our in-venv sudospawner)
 c.SudoSpawner.sudospawner_path = '/opt/jupyterhub/venv/bin/sudospawner'
-c.SudoSpawner.debug = True
-c.SudoSpawner.mem_limit = '2M'
-c.Spawner.debug = True  # redundant ?
+
+# Generic spawner config
+c.Spawner.mem_limit = '2M'
+c.Spawner.debug = True
 c.Spawner.KernelSpecManager.whitelist = {'javascript'}
 c.Spawner.notebook_dir = '~/notebooks'
-
+c.Spawner.environment = {
+    {% if jupyterhub_system_locale %}
+    'LANG': '{{ jupyterhub_system_locale }}',
+    {% endif %}
+    'NODE_PATH':'/usr/lib/node_modules',
+}
 
 ### AUTH ###
 ## Restrict users able to log in to a unix group