Safely testing my students’ PHP graded labs with docker containers

During the course of Web architecture and applications, our students had to deliver a Silex / Symfony Web app project which I’m grading.

I had initially hacked a Docker container to be able to test that the course’s lab examples and code bases provided would be compatible with PHP 5 even though the nominal environment provided in the lab rooms was PHP 7. As I’m running a recent Debian distro with PHP 7 as the default PHP installation, being able to run PHP 5 in a container is quite handy for me. Yes, PHP 5 is dead, but some students might still have remaining installs of old Ubuntus where PHP5 was the norm. As the course was based on Symfony and Silex and these would run as well on PHP 5 or 7 (provided we configured the right stuff in the composer.json), this was supposed to be perfect.

I’ve used such a container a lot for preparing the labs and it served me well. Most of the time I’ve used it to start the PHP command line interpreter from the current dir to start the embedded Web server with “php -S”, which is the standard way to run programs in dev/tests environment with Silex or Symfony (yes, Symfony requires something like “php -S localthost:8000 -t web/” maybe).

I’ve later discovered an additional benefit of using such a container, when comes the time to grad the work that our students have submitted, and I need to test their code. Of course, it ensures that I may run it even if they used PHP5 and I rely on PHP 7 on my machine. But it also assures that I’m only at risk of trashing stuff in the current directory if sh*t happens. Of course, no student would dare deliver malicious PHP code trying to mess with my files… but better safe than sorry. If the contents of the container is trashed, I’m rather on the safe side.

Of course one may give a grade only by reading the students’ code and not testing, but that would be bad taste. And yes, there are probably ways to escape the container safety net in PHP… but I sould maybe not tempt the smartest students of mine in continuing on this path 😉

If you feel like testing the container, I’ve uploaded the necessary bits to a public repo :

Using org-mode and org-reveal for teaching material

I’ve finally put together in a single example repo an example of the way I manage teaching material with org-mode.

It needs more docs and work, but should be usable. Docs and demo at and the Gitlab repo at for those curious.

It doesn’t intend to be a full-fleshed product (also the name is just a codename), but release early, release often, they said 😉

Of course, teaching requires much more stuff than slides and handbooks, but eh, that’s my contribution for the moment.

Update 2017/05/18: I’ve updated the docs and repo to include generation of a “printed slides deck” in PDF, using DeckTape.

Deploying parallel Eclipse installations for teaching labs

I’ve worked on documenting and automating the deployment of Eclipse installations for several teaching labs of Telecom SudParis.

The recently introduced Eclipse Installer (Oomph) allows to install several parallel Eclipse installations containing diverse versions of Eclipse and bundles, so that each specific installation only contains a limited set of features, and that common plugins are pooled in a shared space.

This allows to deploy different Eclipse installations for different course labs, containing only the needed features, and minimizing the disk space needed for the whole.
Previously, we installed pretty much everything in a single place (yum install eclipse*), which lead to providing students with all possible languages support and features, on every machines, by default.
One of the main expected benefits of the new approach is to minimize Eclipse startup times, but this should also help avoid conflicting plugins.
If the experiment proves useful, we’ll then have one Eclipse installation for each needing computer science lab, all under different subdirs of /opt/eclipse/. For instance students registered in CSC4101 will start Eclipse by executing /opt/eclipse/CSC4101/eclipse/eclipse, giving them features for PHP and Symfony development (resp /opt/eclipse/CSC4102/eclipse/eclipse for CSC4102, for Java + Maven, etc.).

I’ve made available a document which explains the process, which was originally documented using org-mode’s babel feature which allows to write “litterate devops” documents containing executable instructions. I’ve used a Vagrant + Virtualbox setup to create the installation inside a Fedora VM, which mimics the target system for our lab machines.

The git repo of the corresponding project should be accessible for anyone interested.