Wednesday, April 2, 2014

Introductory Firefox core development events : Setup issues

I'll be posting something about my overall experience at ProgramIIEST and MozSetup@IITKGP later this week, but I wanted to get this out there first. I may also post something about improving the good-first-bug system.


This post is partially meant as an extension to Deb's post on the same issue. Most of the contents in this post come from discussions with Deb, Sankha, Saurabh, and others: thanks, everyone!

So till now I've participated in two MozSetup-style events. One in IIT Bombay (where i was a participant), and one in IIT Kharagpur (where I was a volunteer/mentor). And one major issue that's there is setup. Basically, getting participants to come with a build system is rather nontrivial, and can be a turn-off in cases. Plus, some participants are on Windows (on the other end of the spectrum, some are on Arch), and it's harder to sort this out. Internet is not something to rely on either.

Besides that, build times are long, especially on systems like mine:
At the IITB event, I had spent quite a bit of time getting a build ready. Fortunately I was able to create a couple of patches without testing, but that's certainly not the ideal way to go. Firstly, getting started takes up a huge chunk of time, and it's a bit overwhelming to have the participants learn and understand the entire process. It's far better to get them involved in writing code and let them figure out the details of setting it up at their leisure.

At the Kharagpur event, I had planned on having some lab machines with a full Nightly build on them so that the students could test and make their patches on this system. This might have worked out, but we didn't have time (or lab access) the day before to initialize this. In the end, we had one machine with a full build on it, and another machine that was built later during the event. I had planned to rsync the built objdirs across systems, but somehow that didn't work even though I'd kept everything in a username-agnostic location (/opt). This is something I'll look into later.

But it turns out there's an easier way to do things than to run full builds on the spot. @Debloper had the interesting idea of using OpenStack for this, and after some discussions it was basically to have an OpenStack instance where we create a VM with a full build environment, and allow participants to fork this VM and do all their coding/testing there (via ssh -X). This requires some investment in maintaining an OpenStack instance, but overall it's a viable way to go. We can also allow participants to keep access to the instance for some time period to make transition to development on their own systems much easier.

As an alternative to this, I had the idea of using flash drives instead of VMs. One way to do this is to install a persistent Ubuntu system1 on a 16 GB flash drive, install the prerequisites, and build. This pen drive can then be booted into and used regardless of the user's system. It's persistent, too, so it can be used in the long term as well. It has the drawback of being a bit slower, though. Also, this drive can be quickly cloned via dd in preparation for an event. If a user wishes to install it baremetal, they can do so manually with dd and update-grub.

The other option is to make an Ubuntu live flash drive, but to customize it via squashfs and chroot and add the required packages along with a full build. Here, there won't be persistent storage, so anyone trying it out by booting into the flash drive will lose their work on reboot. However, this is easier to install baremetal since the standard installation process will work, and a baremetal install is faster, too. Again, the ISOs can be cloned.

If we want this to be scalable, we can eventually ask Mozilla to build these ISOs once every X days (or once every clobber) and put them up for download, much like Nightly builds. As far as I can tell, this won't create much extra strain on their resources. Then event organizers all over the world just have to burn the ISOs to some flash drives the night before, which is something very feasible.

The cherry on top of this method (Deb's awesome idea) is that these flash drives can double as swag. A mozilla-branded drive is something pretty cool, especially if it contains everything you need for contributing to Firefox from wherever you are. The details of this depend on budget and all, but ... it's an option :)

There will still be architecture issues and speed issues, but these can be solved with some work. Using an older Ubuntu version like Backtrack does is one way to make things faster, and we can always have a couple of AMD flash drives ready.

I hope we get to try this method out at a similar event (maybe the upcoming Kolkata one). There are a lot of avenues to explore here, and a lot of room for improvement, but overall it seems like a promising way to fix the setup issues at such events.


1. Or Fedora, but I haven't yet worked out the details for Fedora. I'll be trying this out when I have time.

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