2. Copy Jupyter App

We will begin by first copying over a pre-built example Jupyter app.

Warning

This example Jupyter app will not work out of the box and requires each center to develop and maintain it themselves. The goal of this tutorial is to:

• get a working Jupyter app running at your center
• introduce you to app development and make you an Interactive App developer

2.1. Steps to Copy

1. We do all of our app development in our Open OnDemand sandbox directory:

   # Create the sandbox directory if it doesn't already exist
   mkdir -p ~/ondemand/dev
   
   # Change our working directory
   cd ~/ondemand/dev
   

   Note

   Open OnDemand looks for apps in special directories on the file system. Two types of apps in particular are system apps and sandbox apps.

   system apps

   These are apps that all users have access to and appear in the Dashboard dropdown menus. They are installed on the local disk with very permissive file permissions.

   Located on the file system under:

   /var/www/ood/apps/sys/<app_directory>
   

   This system app can be accessed by navigating in your browser to:

   https://ondemand.my_center.edu/pun/sys/<app_directory>
   

   If this is a system Interactive App (Dashboard plugin), then it can be accessed by navigating to:

   https://ondemand.my_center.edu/pun/sys/dashboard/batch_connect/sys/<app_directory>/session_contexts/new
   

   sandbox apps

   These are apps that only the owner of the app can access irrespective of file permissions. Typically you develop apps in your sandbox before moving them to the production system location.

   Located on the file system under:

   ${HOME}/ondemand/dev/<app_directory>
   

   Can be accessed by navigating in your browser to:

   https://ondemand.my_center.edu/pun/dev/<app_directory>
   

   Note that we just replaced sys with dev in the URL when going from system app to sandbox app.

   If this is a sandbox Interactive App (Dashboard plugin), then it can be accessed by navigating to:

   https://ondemand.my_center.edu/pun/sys/dashboard/batch_connect/dev/<app_directory>/session_contexts/new
   

2. Download our example Jupyter app using git:

   git clone https://github.com/OSC/bc_example_jupyter.git jupyter_app
   

3. Change our working directory:

   cd jupyter_app
   

4. Wipe the previous git history so we have a fresh app:

   rm -fr .git
   

5. Unlike system apps you do not need to install this app to another directory. As it is already in the special sandbox directory the app is already accessible from your browser.

Note

It is recommended you version your new app using git.

# Create a local repository
git init

# Stage all the files under app
git add --all

# Make your first commit
git commit -m 'my first commit'

2.2. Verify it Works

You can now test that this app is functional by visiting your local OnDemand server in your browser:

GET /pun/sys/dashboard/batch_connect/dev/jupyter_app/session_contexts/new HTTP/1.1
Host: ondemand.my_center.edu

Note

By default all browsers send GET requests when navigating to a URL. The above block can be accessed simply by navigating to the following URL in your browser:

https://ondemand.my_center.edu/pun/sys/dashboard/batch_connect/dev/jupyter_app/session_contexts/new

Where you replace ondemand.my_center.edu with your domain.

Keep this link handy as you will want to access it everytime you make changes to the app code to test your changes.

Notice that we have dev/jupyter_app in the above URL. This tells the Dashboard app (which is responsible for launching these Batch Connect plugins) to search for the app in a directory called jupyter_app in your OnDemand sandbox directory.

Warning

The app will probably display a warning about requiring a cluster. This is perfectly fine. Continue on to the next section to learn about customizing the app.