One Year at Mozilla

July 18, 2012 at 12:00 AM | categories: Mozilla, Firefox, Sync

It is hard to believe that my first day as a full-time employee of Mozilla was one year ago today! But, here I am. And, I'd like to think the past year is worth reflecting on.

So, what have I been doing for a year? Good question!


  • First patch and commit to Firefox: bug 673209. Yes, my first patch was to It scared me too.
  • Number of non-merge commits: 133
  • Number of merge commits: 49
  • Number of reviews: 31
  • Favorite commit message: 88d02a07d390 Fix bug 725478 because we run a buggy Python released almost 5 years ago; r=tigerblood (it was a bustage follow-up).
  • Biggest mistake: buildbotcustom change to packaging turned every tree red. All of them. Including release. I think I have philor on record saying it is the worst burnage he's ever seen. Mission accomplished!

Major User-Facing Features:

  • Wrote add-on sync for Firefox (with help from many others, especially Dave Townsend and Blair McBride).
  • Principle reviewer for Apps in the Cloud (apps sync) in Firefox. (Are reviewers allowed to take credit?)

Honestly, when I see that list, I think that's all? It doesn't feel like a lot, especially since I work on a major user-facing feature (Firefox Sync). I do contribute to more. But, if you ask me what the most significant impact was, I don't think I can call anything else out as major.

There are certainly a lot of minor things:

  • Actually managed to understand how Firefox Sync works, including the crypto model. I even documented it! I don't think I knew any of that when I started (I basically knew that Firefox Sync was using strong client-side encryption. What that meant, I had no clue.)
  • Filed initial bugs (including some patches) to compile mozilla-central on Windows 8 and MSVC 2011. By the time people started working on Metro development, mozilla-build, configure, and the like already supported building.
  • Configured Android Sync Jenkins Builder. I'm told the Android Sync team loves it! You gotta love all the built-in dashboards. I really wish we had this for mozilla-central.
  • Made xpcshell test harness write xUnit files. Machine readable output of test results, baby!
  • Implement send tab to device API in Firefox Sync. Too bad we don't have UX to use it :(
  • Implemented testing-only JavaScript modules. So, instead of the hack that is [head] files in tests, you can Cu.import("resource://testing-common/foo.js");
  • Made test package generation quieter. This made build logs about 30% smaller. This means you can get at build results faster.
  • Hacked around with JavaScript code coverage using the JS Debugger API. Failed in the process. But, I learned a lot about the JS Debugger API, so I consider it a win.
  • Rewrote Firefox Sync's record reconciling algorithm. The old one was full of subtle data loss corner cases. The new algorithm is much more robust (we think - even with 3 reviewers there was still some head scratching).
  • Emancipated lots of generic JavaScript code from the Sync tree into the a services-common package. This anticipated Apps in the Cloud and notifications' requirement to use this functionality and allowed those projects to get going quicker. At this point, we're effectively running a mini Toolkit. We really need to port some of this upstream.
  • Helped design the next version of the HTTP service to be used by Sync.
  • Implemented a standalone JavaScript implementation of the above. The production server used by Mozilla runs on Python (running the Python server in Mozilla's test environment would be too difficult). The server was also implemented using just the spec. This allowed us to clarify many parts of the spec. The Python functional tests can also be executed against the JS server. This gives us confidence that functionality is equivalent and tests hitting the test/JS server will behave the same as if they are hitting the production Python server.
  • Implemented a standalone JavaScript client for the above service. Previously, all the logic for this was scattered over about a dozen files and was notoriously difficult to audit and update. I also think it is a decent example of good code. Clean. Highly documented. No hacks.
  • Reviewed a skeleton for the notifications service, which will eventually power browser notifications in Firefox.
  • Build system patches to better support Clang. Thankfully, Rafael EspĂ­ndola has been our Clang champion as of late and is now ensuring the bleeding edge of Clang does not break the tree. Thanks, Rafael! (I actually think he is in the process of switching our OS X builds to use Clang as I type this!)
  • Worked with security and crypto people to devise the security model behind the next version of Firefox Sync. (Brian Warner and Ben Adida have been doing most of the crypto work. I'm mostly on the sidelines making sure they design a system that can easily interop with Sync.)
  • Helped devise the next version of Sync's server-side storage format. This will make the next version of Sync faster and able to hold more data at lower server cost.
  • Gave lots of love to documentation at (especially the Sync docs). It's almost at the point where others can implement Sync clients without having to ask one of the fewer than 10 people on the planet who actually know.
  • Contributed many small patches to the build system. Mostly general cleanup so far. Although, I have much bigger plans in the works.
  • Many miscellaneous small things. (I get distracted easily.)

Well, that list doesn't seem too shabby. But, a lot of it is smaller ticket items. I don't think there's anything there worth writing home about. Whatever. The future is looking bright for Firefox Sync (Persona integration will make Sync usable by millions more) and new sync backends are coming (including search engine sync). So, I'm fine with not having a longer list of big ticket contributions after only a year.

On Ramping up at Mozilla

I will be the first to admit that I had a difficult time getting into the groove at Mozilla and my first months (dare I say my first half year) were unproductive by my personal standards.

I can't say I wasn't warned. My manager (Mike Connor) told me multiple times that it would happen. I was skeptical, insteading rationalizing that my previous track record of learnly quickly would hold. He was right. I was wrong. I got fat from the humble pie.

There are a few reasons for this. For starters, I was starting a new job. It's almost impossible achieve 100% productivity on your first day. Second, I was working with tools I knew little about, including JavaScript and especially including the flavor of JavaScript used inside Firefox. (Short version: the JavaScript within Firefox is awesome in that it implements bleeding-edge features of the language. Unfortunately, the JavaScript inside Firefox/Gecko is contaminated by this blight called XPCOM. It makes things ugly and not very JavaScript-y. XPCOM also makes the learning curve that much harder because now you have to learn multiple technologies at the same time.) It was daunting.

Not helping matters was the fact that Firefox Sync is complicated. Syncing data is in of itself a difficult problem. Throw in remote servers, an HTTP protocol, a encryption, and interaction with systems inside Firefox that are themselves complicated, and you have a hard problem. My first months were literally spent being a thorn in Philipp von Wieter^H^H^H^H^H^H philikon's side, barraging him with an endless stream of questions. I am forever in beer debt to him because of this. When Philipp left the team to work on Boot 2 Gecko and the rest of the Firefox Sync team was retasked to work on Android Sync shortly thereafter, I was on my own little island to manage Firefox Sync. I kind of felt like Tom Hanks' character in Castaway.

If I have one piece of advice for people starting at Mozilla it's this: be prepared to be humbled by your own ignorance. There is a lot to learn. It's not easy. Don't feel bad when you struggle. The payoff is worth it.

On Life at Mozilla

Despite the hurdles I initially faced ramping up at Mozilla, life at Mozilla is great. This mostly stems from the people, of course.

If you are just looking for technical excellence, I think Mozilla has one of the highest concentrations of any company in the world. Sure, larger companies will have more amazing individuals. But, the number per capita at Mozilla is just staggering. I don't know how many times I've met or talked with someone only to find out later they are considered to be one of the best in his or her respective field. Reading Mozilla's phonebook is like looking at a Who's Who list. For someone like me who loves being a sponge for knowledge, Mozilla is an environment in which I can thrive. Just thinking back at everything I've learned in the past year makes my mind asplode.

On the personal front, the personalities of Mozillians are also top notch. People are generally helpful and supportive. (They need to be for an open source project to thrive.) People recognize good ideas when they hear them and there is comparatively few political battles to be won when enacting change. People themselves are generally interesting and passionate about the world and the work they do. If you are living inside the Mozilla bubble, you may not realize how lucky you have it. I could give specific examples, but I'd be writing all night. Just take my word for it.

If you need something to whet your appetite, just check out the zaniness that is Mozilla Memes. I don't expect you to understand many of the posts unless you are a Mozillian or follower of Reddit and know what internet memes are. But, if you are either, it pretty much sums up a large part of the culture for you. Sometimes I feel like I'm living in one giant, happy meme.

One of the aspects I love most about working at Mozilla is I finally feel that my career interests are aligned with an organization I philosophically agree with. Just read the Mozilla Manifesto. What's not to like?

This is one of the primary factors that convinced me to join Mozilla. After Microsoft acquired the startup where I had my first post-college job (Tellme Networks), I could never hold my head high in Silicon Valley among my friends in the tech sector. Normal people and those outside of Silicon Valley were like, "Microsoft, cool!" But, something just didn't feel right about saying I worked for them. I felt like I was working for the Empire while I really wanted to be working for the Rebel Alliance. I felt like I had to atone for my time at Microsoft. I felt like I needed to cleanse my soul. Mozilla was an obvious answer.

(I don't mean to disparage Microsoft. I actually think the culture has changed since the days when their behavior earned them the reputation that Silicon Valley stills holds them accountable for. Still, I would not work for them in Silicon Valley. Anyway, I'm not here to talk about the past.)

Mozilla is an organization I'm proud to work for. I exercise that pride by frequently wearing my awesome Firefox hoodie. Nearly every time I do, random people come up to me and say how they love Firefox and/or what Mozilla does for the world. Every time they do, it brings a smile to my face. This constantly reinforces what I know to be true: that I'm working for a great organization.

Future at Mozilla

I'm already looking forward to the next year at Mozilla. It is already shaping up to be much, much more productive than my first.

On the roadmap, all of my hacking about with the build system is about to pay dividends. Ever since my first day at Mozilla I have been frustrated with the build system and the developer experience one must go through to contribute to Firefox. After many months of casual (mostly evenings and weekends) experimentation, my work is about to pay off.

I have successfully formulated a plan of attack and helped convince others this is what we need to do. We have since committed to the fundamental components of that plan and are tracking its progress. (I don't mean to take sole or even primary responsibility for this as the credit resides with a number of people. But, I would like to think that the dozens of times I championed aspects of this plan in IRC and in hallway chats before I was the first person to articulate it in a post helped lay the groundwork for the eventual acceptance of this project.) Once we see progress on this project, great things will come from it. I promise.

My work towards making the build system faster had an unintended consequence: the creation of a new tool that serves as a frontend to the build system. One day, I took a step backwards and realized that the potential for such a tool is much greater than simply interacting with the build system. So, I extracted that work from my build system hacking and polished it up a bit. It is now one review away from landing. When it does, thousands of Firefox developers will have a much better experience when developing Firefox. And, my hope is for many more features to follow to make it even more awesome, especially for first-time contributors. I believe this is important to help advance Mozilla's Mission.

Improving the developer experience of Firefox is exciting and it will likely make a lot of people really happy. But, it's neither the most exciting nor most important project I'll contribute to in the upcoming year. The most exciting and important project for me will be refactoring Firefox Sync to make it faster, more robust, sync more data, and, most importantly, usable by more people.

Firefox Sync stands out from similar products in that it keeps your data safe. Really safe. I blogged about this previously. But, I intentionally kept the tone of that post neutral and factual. The truth is that the security model of Firefox Sync makes it look like nearly all other products aren't even trying. I take immense pride in working on a data-sharing feature that makes users' lives better without undermining security. Firefox Sync stands in rare company in this regard.

Unfortunately, in our zeal for the best security possible, we designed a product that isn't usable by the majority of people because it is too complicated to set up and is prone to losing your data. In the end, this doesn't really serve the overall Firefox user base.

We've been hard at work devising the next version of Firefox Sync which will retain the optimum security and privacy settings of the existing product while extending usability at nearly-comparable security and ofer data recovery to the vast majority of our users. This is huge.

Yeah, I'm pretty damn excited about my next year at Mozilla.