HTTP2 – the next step

IETFThe HTTPbis working group of the IETF had an interim meeting in Zurich January 22nd to 24th. I participated from remote and I listened in on the discussions over webex and followed the jabber room while the meetings were going on, addressing HTTP2 protocol issues one by one ironing out quirks and progressing forward.

I won’t bore you with details why I wasn’t present in Zurich.

Here’s a couple of quick and brief reflections from my perspective:

Listening in from remote like this is not at all adequately compensating for not being there. A room full of people discussing something is really hard to follow from remote and completely impossible to interact with. It is better than not being able to listen in at all, but it is certainly not a replacement for being there.

It is amazing how much faster people can come to conclusions and fix issues when being in the same room. Issues that have been lingering in the tracker for a very long time could be dealt with and closed within minutes. Things like what to call the protocol in ALPN or to remove the ability to switched off flow control. Not all issues of course…

HTTP2 draft-09 that soon will become draft-10 to reflect the updates from this meeting and more, is from my perspective quite far in its process. It is clearly at a point that seems to be OK with most people and the discussions are now just about details. Of course the devil is in the details and I’m not saying it can’t take a long time to settle on them, but the structure and main concepts of the protocol are probably now established.

There were not very many proxy or server people at the interim. Most of the people seemed to be client-side oriented and some service oriented. I’m personally client-side biased myself but I hope this doesn’t lead to us deciding on things that the “other side” will have problems with down the line.

Firefox nightly supports HTTP2 draft-09 (for https:// URLs) and twitter supports it server side. Enable it in the browser by entering “about:config” in the URL bar and change the config entry called “network.http.spdy.enabled.http2draft” to true. Done.

Some of the biggest HTTP2 changes brought up compared to what draft-09 says include:

  • no more ability to switch off flow control
  • the prioritization field/concept “weighted dependency tree approach”
  • >= TLS 1.2 with ephemeral ciphers
  • MUST not use TLS compression
  • tolerant to TLS false start or at least must accept/buffer application layer data
  • padding

There was also a whole lot of discussions about TLS for http:// urls, proxys, MITM for SSL, opportunistic encryption and more but I believe most of those issues remained at the same position as before – I missed out on parts of the last afternoon so I may have missed some details. It’ll all be revealed in draft-10 and the mailing list I’m sure!

Update: the minutes from the interim meeting.

http2-drawing

My first Mozilla week

Working from home

I get up in the morning, shave, eat breakfast and make sure all family members get off as they should. Most days I walk my son to school (some 800 meters) and then back again. When they’re all gone, the house is quiet and then me and my cup of coffee go upstairs and my work day begins.

Systems and accounts

I have spent time this week to setup accounts and sign up for various lists and services. Created profiles, uploaded pictures, confirmed passwords. I’ve submitted stuff and I’ve signed things. There’s quite a lot of systems in use.

My colleagues

I’ve met a few. The Necko team isn’t very big but the entire company is huge and there are just so many people and names. I haven’t yet had any pressing reason to meet a lot of people nor learn a lot of names. I feel like I’m starting out this really slowly and gradually.

Code base

Firefox is a large chunk of code. It takes some 20 minutes to rebuild on my 3.5GHz quad-core Core-i7 with SSD. I try to pull code and rebuild every morning now so that I can dogfood and live on the edge. I also have a bunch of local patches now, some of them which I want to have stewing in my own browser for a while so that I know they at least don’t have any major negative impact!

Figuring out the threading, XPCOM, the JavaScript stuff and everything is a massive task. I really cannot claim to have done more than just scratched the surface so far, but at least I am scratching and I’ve “etagged” the whole lot and I’ve spent some time reading and reviewing code. Attaching a gdb to a running Firefox and checking out behavior and how it looks has also helped.

Netwerk code size

“Netwerk” is the directory name of the source tree where most of the network code is located. It is actually not so ridiculously large as one could fear. Counting only C++ and header files, it sums up to about 220K lines of code. Of course not everything interesting is in this tree, but still. Not mindbogglingly large.

Video conferencing

I’ll admit I’ve not participated in this sort of large scale video conferences before this. With Vidyo and all the different people and offices signed up at once – it is a quite impressive setup actually. My only annoyance so far is that I didn’t get the sound for Vidyo to work for me in Linux with my headphones. The other end could hear me but I couldn’t hear them! I had to defer to using Vidyo on a windows laptop instead.

Doing the video conferencing on a laptop instead of on my desktop machine has its advantages when I do them during the evenings when the rest of the family is at home since then I can move my machine somewhere and sit down somewhere where they won’t disturb me and I won’t disturb them.

Bugzilla

The bug tracker is really in the center for this project, or at least for how I view it and work with it right now. During my first week I’ve so far filed two bug reports and I’ve submitted a suggested patch for a third bug. One of my bugs (Bug 959100 – ParseChunkRemaining doesn’t detect chunk size overflow) has been reviewed fine and is now hopefully about to be committed.

I’ve requested commit access (#961018) as a “level 1” and I’ve signed the committer’s agreement. Level 1 is entry level and only lets me push to the Try server but still, I fully accept that there’s a process to follow and I’m in no hurry. I’ll get to level 3 soon enough I’m sure.

Mercurial

What can I say. After having used it a bit this week without any particularly fancy operations, I prefer git so much more. Of course I’m also much more used to git, but I find that for a lot of the stuff where both have similar concepts I prefer to git way. Oh well, its just a tool. I’ll get around. Possibly I’ll try out the git mirror soon and see if that provides a more convenient environment for me.

curl

What impact did all this new protocol and network code stuff during my work days have on my curl activities?

I got inspired to fix both the chunked encoding parser and the cookie parser’s handling of max-age in libcurl.

What didn’t happen

I feel behind in the implementing-http2 department. I didn’t get my new work laptop yet.

Next weekDaniel's work place

More of the same, land more patches and figure out more code. Grab more smallish bugs others have filed and work on fixing them as more practice.

Also, there’s a HTTPbis meeting in Z├╝rich on Wednesday to Friday that I won’t go to (I’ll spare you the explanation why) but I’ll try to participate remotely.

This is my first day at Mozilla

I’m now a Senior Network Engineer at Mozilla. Today is my first day as an employee. Here’s my summary of how I got here and how the process has been so far, from my perspective.

Mozilla is an American company

OK, that’s not news to anyone and neither is it to me. I’m starting off with this because I’m not American. I’m a Swede, and I live in Sweden. When working and communicating with my fellow people at the mothership I of course get the slight cultural differences that are American versus Swedish. It’s not a problem because I’ve gotten quite used to working with Americans at work over the years but going through an entire recruiting and starting-a-new-job process entirely in English with Americans is new to me.

Interviewing

So when I was opening up to my social network to start looking for new assignments since I decided to end my previous one, I was approached by a friend who works for Mozilla. Of course I was interested to work for Mozilla!

So I had a Skype interview with a recruiter first, and then with two engineers. During evenings of course since Mozilla like many other tech companies are mainly in the west coast of the US, meaning -9 hours from me.

After those initial interviews I had to struggle with myself since I was in this luxury position of having no less than two other very interesting projects being suggested. How do you pick the best one out of three really good alternatives? I actually had to wrestle with all the details and factors involved and I decided that this lead was the best out of the three. If Mozilla wanted me, I’d go for that option.

So I took 4 days off from my current work and flew out to Mountain View California one day in November 2013. It takes some 17 hours to get there, I had a spare day to get somewhat adjusted to the time zone and then I fired off no less than five 45 minute interviews in a row that Wednesday. Then I got a ride back to SFO and I took the plane back home.

I’ve been a consultant for 16 years and I’ve done way over 30 projects during this time. I’ve been interviewed for all of them, and a bunch more that I didn’t end up getting. You can say I’m quite experienced in getting interviewed for work. What I’ve learned is to stay honest, just be me and have an as good time as possible but in the end it really isn’t possible to tell how the other end interprets me an my answers and if I match what they desire.

Getting hired

They didn’t reject me. I got the offer. I said yes. I signed the papers.

So one of the most frequent questions I’ve got when I told friends about my new job:

So you’re not gonna be a consultant anymore?

And no, I’m not. This option only came in the form of an employment or not at all, and I decided I wanted to do this rather than the alternatives. I’ve done consultant based development since 1996 and now I’m not anymore! Of course I still have tight bounds to Haxx and I certainly won’t exclude that I’ll return there one day.

My agreement also allows me to spend some time on curl development. Don’t you worry about that. I feel confident that I will only increase my commitment and efforts there.

Getting anxious

Once I had accepted the job I immediately wanted to start and by golly I got a harder time trying to motivate myself do good the period until that assignment ended.

I’ve had more phone meetings, I’ve checked out code and repeatedly rebuilt Firefox since then, I’ve read Bugzilla entries and perhaps most of all I’ve participated in Mozilla’s “onboarding program” which is a web based system that gives me tasks and asks questions and provides information, all in an effort to give them the information about me that they need and give me the proper info on Mozilla, what it is about, its background and what we’re doing ahead. (See how smoothly I used “we” there?)

Anxiously waiting for The Day. This may sound a bit melodramatic to some, but I do kind of feel like my life is changing a bit now into something it wasn’t before.

Starting a new job working remotely at day one

Today is The Day. I assume not everyone of you reading this have done it, but I start my first day at my new work for my new employer on the upper floor of my house, completely alone. I work from home, remotely and I’m also mostly isolated from a large portion of my colleagues by time zones.

So I grab my coffee and walk up the stairs to my home office. I sit down and I dive in. Source code. Lots of source code.

There’s a steep learning curve here, but I’m not afraid of some hard work and I like a challenge, I like code, I like open source and I like internet protocols. And I have good coffee.

Mozilla. I’m here. I’ve started. Today.

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