launchpadblog

I do not like the Launchpad branch page. It is rarely informative and I would like to ignore it, but there are a few tasks that I can only perform form that page. I think the page could be better if it were possible for me to state the branches’s purpose.

I sat down the Huw, the Launchpad team’s designer to discuss the page almost two years. He was struggling to make sense of the the branch page from a developer’s perspective. At that time I concluded that I disliked the page because it treats all branches as if they have the same needs, which ignores the fact that every branch has a purpose. A branch’s purpose determines what I need to know and what actions I can take. I saw two purposes at the time, but I recently concluded in a sleepless state that there are five purposes. Maybe this was a delusion created by the fever. Let’s see if I still think that at the end of this post.

The branch page is missing:

• A statement of intent
  What is the branch’s purpose? This determines the action I can perform and the information I need to see. Is this branch trunk, a supported series, for packaging, a feature, or a fix?
• A record of content
  I want to browse the files of some branches, while other branches I only care about the diff.
• A testament of accomplishment
  A branch’s purpose determines its goal. The goal of most branches is to merge with another branch. Some branched though must create releases or packages.

The features a branch needs are mostly determined by the how long the branch is expected to live:

• Short-lived branches
  The branch is often based on trunk, its purpose is to fix or add a feature (Bug or blueprints), and it goal it is to merge into its base branch.
• Long-lived branches
  The branch is often the basis of other work. It is the sum of many merges, often summarised as milestones. The goal of the branch is to create releases.

Trunk branch

The most important branch to every project is the one designated to be trunk. This branch will live for months, or years. This is the branch I use as the basis for my changes. It is the goal of most derived branches to merge with this branch. The goal of trunk is to make releases.

There is no need to show me which bugs are fixed or blueprints (features) are implemented in trunk. Trunk is everything to the project. When we say there is a bug in a project, we really know that bug is in trunk. Launchpad could change how it models bugs to make this case clear. The bug tracker or specification tracker are the only tools that can adequately explain which bugs and blueprints were closed. I might be interested in which bugs and blueprints were recently fixed in trunk though.

The merge action does not make sense. It is the goal of other branches to merge with trunk…trunk does not merge with other branches! Well this is not entirely true in the packaging case, which I will explain shortly. I am interested is seeing the list of recently proposed merges into this branch. The branch log shows me which branches were merged.

I want Launchpad to shown me the bugs and blueprints that the project drivers plan to fix. Will my bugs be solved soon? Can I contribute? Launchpad actually can show me this on the series page. Launchpad separates the concept of planning changes (feature and fixes) from branch. There is good reason for this, but the separation of information creates a chasm that many developers fail to cross.

We commonly organise change into milestones, and each milestone may culminate in a release. A series of milestones represent continuity and compatibility. Distributions have a series without having a trunk branch. There are also projects that do not produce code, but have bugs and blueprints. Launchpad is also a registry of projects and releases that are packaged in Ubuntu.

Launchpad creates a trunk series for every registered project because we believe all projects should state their intent and distinguish between different bases of code. But where is the code? Where is my branch? I commonly see projects with series information without a branch, and I commonly see projects without series information, with tremendous branch activity. It is difficult to contribute when you cannot see what is happening and what needs to happen. Project maintainers are equally frustrated; Launchpad is not helping them to create releases from their trunk branch.

Launchpad asks me to link a branch to a series, but I think most developers want to state that their branch is the trunk series, or is a supported series. The branch is elevated to a new role and it gets the features that the role needs. I want one page about the trunk branch, not a page about planning and a page about branch metadata.

Supported series branch

A supported branch represents a previous project release. It is a historic version of trunk with its own bugs and features. Like trunk, the linked bugs and branches do not make sense, nor do I want to merge a supported branch into another branch. A supported branch can live for months or years. Some fixes (branches) will be merged into the support branch. Feature branches are never merged into supported branches.

In the case of a supported branch, I most want to know the milestones/releases that represent the life of support. I want to know which fixes in trunk will be backported to the supported branch. I might be interested in knowing the fixes (branches) that were recently merged.

Packaging release branch

A packaging branch contains additional files needed to create an installable package from a project’s release. A packaging branch often has counter-part branch, usually a supported branch, but sometimes trunk. Thus the packaging branch lives for months or years. The packaging branch may only contain the extra files to create a package using a nesting recipe, or it contains repeated merges of the counter-part branch. I am only interested is seeing the differences from the counter-part branch. I do not want to browse all files in the branch.

Packaging branches have their own set of bugs — the files introduce bugs and yet some of the patch files fix bugs in the counter-part branch. Thus we might image that the packaging branch is the sum of the bugs in the supported and packaging branch, minus the fixes provided by patches.

Packaging branches are often managed by different people from the project’s developers. Their skills and permissions are often different too. A patch to expediently fix a bug in the packaging branch might take much longer merge into the supporting branch where the bug originates.

Feature (blueprint) branch

A feature branch adds new functions to the code. It is short-lived, measured in days or weeks. The branch is based on trunk and is goal is to merge with trunk.

Feature branches need all the features that the current branch page provides. The feature branches has blueprints that specify what functions are being added and the criteria to know when the feature is done. They may also fix bugs. A recipe can be used to build an unstable package for testing.

Merges are far more complex for feature branches than is implied by the Launchpad’s UI. There are many workflows where a feature branch is actually composed of several branches that might be merged with trunk individually, or they are merged as a whole when the feature us deemed stable. Launchpad should encourage me to merge the branch into trunk, merging into another kind of branch doesn’t make sense. The UI does not properly show that I may merge my feature branch into trunk several times, or that several branches might merge into my feature branch.

I am only interested in seeing the changes from trunk. I do not want to browse all the files in the branch. Since a feature branch can be composed of many branches, I want to see the difference between the merges to understand the revision changes.

Fix (bug) branch

A Fix branch exists to close a bug. The branch is short lived, measure in hours or days. Its goal is to merge with its base branch. The older the branch gets, the more likely that it has failed.

It does not have related blueprints or recipes. I am not interest on seeing all the files and code in the branch; I only care about the changes from base.

A fix branch needs to tell me which bugs it fixes. It must encourage me to merge the fix back into the base branch.

Most fixes are based on trunk and will merge with trunk, but when a bug also affects a supported branch, Launchpad might want to encourage me to propose a backport. Launchpad currently allows me to nominate/target a bug to a series (which is ultimately a branch) when there is no fix. I think this is odd. Project development is focused on trunk, fixes are almost always made in trunk first. Once trunk has the fix, it is possible to determine the effort needed to backport it to a supported branch. If a bug is only in a supported branch, then I think it is fine for Launchpad to allow me to nominate it to be fixed, which implies the fix is already in trunk.

Conclusion

Hurray! I still think there are five kinds of branches which different needs. This issue is like a bad word processor which treats a letter, a report, and a novel the same. A good word processor knows the document’s intent and changes the UI and available features so that I can complete my task without distraction. The current branch page emphasizes what all branches have in common, but it needs to emphasise the differences so that I know what I need to do. There are no plans to change the branch UI, but contributors are welcome to improve Lp. I hope my thoughts will contribute to a proper analysis of features the branch page must support.

Ever wished there was just one feature you’d like to see enabled in Launchpad. Ever wondered when one of the bugs you have taken the time to report and document would be implemented.  Well how about we help you to get these bugs fixed.  Launchpad is a free and open source project, its platform is also open and developed in a transparent fashion. The source code for every feature, change and enhancement can be obtained and reviewed.

This means you can actively get involved in improving it and the community of Ubuntu platform developers is always interested in helping peers getting started. The Launchpad development team are continuously working on areas in Launchpad and other projects but there just isn’t enough time in the day to get every bug fixed, tested, deployed and out there.  What we’d like to help to do is encourage and help users get more involved. We would like to get more of the developer community involved in Launchpad, users who’ve never developed before to experienced hands on developers and show you how to get started. There is documentation written up, but we’re going to explain it a less scary way in  basic steps.

Getting Started

First things first, you need bzr. All of Launchpad’s branches use bzr for source control, so you’ll need to install it using apt-get:

 $ apt-get install bzr

Next, you need to create a space in which to do your development work. We’ll call it ~/launchpad, but you can put it pretty much anywhere you like on your system.

$ mkdir ~/launchpad

Because getting all the ducks in a row to make it possible to do Launchpad work takes a while, we’ve actually got a script that does all the legwork for you. It’s called rocketfuel-setup (see what we did there?) and once you’ve got bzr installed, you can

$ cd ~/launchpad
$ bzr --no-plugins cat http://bazaar.launchpad.net/~launchpad-pqm/launchpad/devel/utilities/rocketfuel-setup > rocketfuel-setup
$ chmod a+x rocketfuel-setup
$ ./rocketfuel-setup

You’ll be prompted for various details, such as your Launchpad username, and you’ll be asked for your password so that rocketfuel-setup can install all the packages that Launchpad needs. After this, you might as well go and have a sandwich, because downloading and building the source code will take at least 40 minutes on a first run.

Once rocketfuel-setup has completed on your machine, your ~launchpad directory will look something like this:

$ ls ~/launchpad/
lp-branches lp-sourcedeps rocketfuel-setup

The only directory you need to worry about in there for now is lp-branches. As the name suggests, this is where your Launchpad branches are stored.

Now that you’re all set up, it’s time to find a bug to fix and get some coding done!

Where to Begin

Now, it’s fair to say that there are plenty of bugs in Launchpad worth fixing. However, it’s even fairer to say that you don’t want to pick on of the Critical bugs as your first effort for Launchpad development, mostly because the Critical bugs are all fairly complex.

Luckily, the Launchpad team maintains a list of trivial bugs – the ones with simple, one-or-two line fixes that we just haven’t been able to get around to yet. You can find it here on Launchpad.

Once you’ve found a bug you want to fix, you need to create a branch for it. There are some utility scripts to make your life a bit easier here. In this case, rocketfuel-branch, which creates a new Launchpad branch from the devel branch that rocketfuel-setup created.

$ rocketfuel-branch my-branch-for-bug-12345

You’ll now find that branch in ~launchpad/lp-branches

$ ls ~/launchpad/lp-branches
devel my-branch-for-bug-12345
$ cd ~/launchpad/lp-branches/my-branch-for-bug-12345

Now that you’ve got a branch to work in, you can start hacking! Before you do, though, you should talk to someone in #launchpad-dev on Freenode about the problem you’re trying to solve. They will help you figure out how best to solve the problem and how best to write tests for your solution. We call this the “pre-implementation call” (though it can happen on IRC) and it’s very important, especially for first time contributors.

Once you’ve had your pre-imp call, you can get coding. Don’t forget that the people in #launchpad-dev are there to help you as you go. Don’t worry if you get stuck; Launchpad is a very large project and even seasoned developers get lost in the undergrowth from time to time. Thankfully, there’s a team of committed people who are able to wade in with machetes and rescue them. I’m going to stop this analogy now, since it’s starting to wither.

What to do once you’re written code

Once you’ve finished hacking on your branch, you need to get it reviewed. Launchpad has a feature that makes this really, really simple, called Merge Proposals. Here’s how it works.

First, commit your changes to your branch (you should have been doing this all along anyway, but just in case…) and push them to Launchpad:

$ bzr ci -m "Here are some changes that I made earlier, with a useful commit message."
$ bzr push
Using saved push location: lp:~yourname/launchpad/my-branch-for-bug-12345
Using default stacking branch /+branch-id/24637 at chroot-83246544:///~yourname/launchpad/
Created new stacked branch referring to /+branch-id/24637.

You can now view the branch on Launchpad by using the bzr lp-open command:

$ bzr lp-open
Opening https://code.launchpad.net/~yourname/launchpad/my-branch-for-bug-12345 in web browser

The page that will open in your browser contains a summary of the branch you’ve pushed, and will look something like this:

You can link it to the bug you’re fixing by clicking “Link a bug report”. If you’ve named your branch something like “foo-bug-12345”, Launchpad will guess that you want to link it to bug 12345 in order to save you some time.

From the branch summary page, you need to create a merge proposal. To do this, click “Propose for merging.” You’ll be presented with this page:

On this page, you’re going to explain what you’ve changed and why. There’s a template for what we refer to as the merge proposal cover letter on the Launchpad dev wiki.

Things you absolutely must include in your cover letter:

• A summary of the problem.
• A summary of your proposed solution.
• Details of your solution’s implementation.
• Instructions on how to test your solution and how to QA it.

Launchpad Clinic – UDS 

At UDS-Q we’re going to run two day with the help of Graham Binns who will be there to help with hands on set up and walk people through their bugs they would like to work on  and figure out where to start.  If you’re interested in taking part in these sessions, please add your name and the bug(s) you are interested in so we can review them ahead of time, there are many to chose from that are tagged with trivial if you want to start there.

We will have a EC2 instance set up of Launchpad to maxamise the time available to work on these areas.

I have been looking for an easy and reliable way to develop and test Launchpad with Internet Explorer. Neither of the two common approaches used by Ubuntu users allows a Launchpad developer to  easily verify that a change works with Internet Explorer. The challenge is to install a working version of Internet Explorer 8 and browse the local development instance of Launchpad. Maybe you can help me find a way to do this?

While Internet Explorer only represents 4% of Launchpad users, recent changes to make Launchpad easier to use made many tasks for IE users impossible to complete. This was unintended. It is a regression, and we treat all regressions as critical issues. The Purple squad reviewed the code and found that a lot of Launchpad JavaScript is disabled for all versions of Internet Explorer without an explanation nor fall-back behaviour. There is no documented way to ensure Launchpad works with Internet Explore, so most developers do not try to make it work.

Microsoft’s developer image of Windows 7 + IE8

Microsoft provides many images of Windows and IE so that Web developers can ensure their code works. The images are compatible with VirtualBox. The installation of the required software is easy, though configuration is tricky. The greatest challenge is creating a reusable Apache2 config for the many Launchpad domains.

Microsoft provides VPC compatible IE images to anyone who wants to verify that a website works with a specific version of IE. You will need about 13GB of disk space to install and run this bloatware that we all have come to expect with Windows. I installed the needed software using these commands:

$ cd /path/to/lots/of/disk/space/VirtualBox/HardDrives

$ sudo apt-get install virtualbox unrar curl

$ curl -L -O "http://download.microsoft.com/download/B/7/2/B72085AE-0F04-4C6F-9182-BF1EE90F5273/Windows_7_IE8.part0{1.exe,2.rar,3.rar,4.rar}"

$ unrar e Windows_7_IE8.part01.exe

I started VirtualBox and changed the preferences to use the path where I had lots of disk space. I created a new Windows 7 instance using the virtual disk. The disk had to be mounted as IDE (SATA failed) and the network was set as bridged.

IE worked perfectly with Ubuntu’s SSO. I could use Launchpad as I expected. In the cases where I expected a problem, I could see behaviours that confirmed my suspicion about the nature of the defect. This setup is ideal for verifying changes on Launchpad’s qastaging and production servers.

Making this setup work with the Launchpad development instance was very difficult. I hard-coded IP addresses to ensure that Windows and Apache knew the *.launchpad.dev sites. My IP address on my local network was 192.168.1.7 at that moment.

• Windows: Added
  c:\windows\system32\drivers\etc\hosts
  which contained
  192.168.1.7 testopenid.dev launchpad.dev code.launchpad.dev answers.launchpad.dev blueprints.launchpad.dev bugs.launchpad.dev translations.launchpad.dev
• Ubuntu: Copied
  /etc/apache2/ssl/launchpad.crt
  to a device that I could mount in Windows [1]
• Windows: Added the launchpad SSL certificate to the Trusted root certificate store
  Internet Options → Content → Certificates → Trusted Root Certification Authorities
• Ubuntu: Updated all references in
  /etc/apache2/sites-enabled/local-launchpad
  of
  127.0.0.88
  to
  192.168.1.7
• Ubuntu: Added
  Allow from 192.168.1.*
  after all occurrences of
  Allow from localhost 127.0.0.0/255.0.0.0

I could login but I discovered that I occasionally needed to rearrange the entries in the Windows hosts file because it has a character limit! Every time my computer’s IP address changes, I need to update the Windows hosts file and the Ubuntu Apache config. I do not mind editing my IP in the Windows host file, but I do not like editing the entries or updating the Apache config. I doubt this setup works for developers using LXCs or other VMs to run Launchpad. I am planning to switch to LXC when Precise is released so this solution may not work for me in a few weeks.

Wine + Winetricks + IE8

Winetricks is a tool that can install and configure IE8 so that it runs on Ubuntu. Installation is very easy, but the UI’s controls and menus are broken. The greatest challenge is that the security behaviour is different from real Windows and IE — the browser thinks real Ubuntu SSO and the entire Launchpad development site is insecure so does not send the required REFERER header.

I installed the needed software using these commands:

$ sudo apt-get install wine winetricks
$ winetricks corefonts ie8

Configure Wine to work with launchpad development instance:

• Add the Launchpad SSL certificate to Wine [1]
  $ wine control
  Internet Settings → Content → Certificates → Trusted Root Certification Authorities
• Run IE
  $ wine iexplore

The UI does not look like IE8, and the broken buttons and menus certainly do not lend any confidence that this works. I can see from the Apache log that my request to https://launchpad.dev/claims to be MSIE 8. I cannot login to the website though. I can see in the logs that the REFERER header was not sent, so the post was rejected. The same is true for posting to the real Ubuntu SSO and Launchpad website — all posted forms fail. IE does this when it believes the browser is posting across a security boundary; it is protecting the user. Since the real Windows 7 + IE8 does not see either the development or production instance as unsecure, I know that something is misconfigured in Wine. I believe the SSL was install correctly because the real IE8 accepted it as did my Ubuntu browsers.

I can make the Launchpad development instance work with the broken Wine IE8 by hacking lp.services.webapp.publication to not requiring the REFERER header for MSIE 8 when the launchpad instance’s host end with “.dev”. This permits me to verify that JavaScript works, but is it really verifying that real IE8 works? I have no confidence in this hack. What else is broken in the setup?

[1] The default Launchpad SSL certificate in the Launchpad tree that is installed by rocketfuel-setup is incomplete. I generated a certificate that properly specified the sites it was for. I installed the better certificate in /etc/apache2/ssl and in my local OpenSSL store. The immediate benefit is that all of my development browsers accept the SSL certificate; not warning about wrong domains. I will add the better certificate to the Launchpad development tree and the script I used to generate and install it.

In my previous post I talked about the pain of having to set up a testing environment for our parallelised test work, and how there were an awful lot of hoops to jump through in order to get something usable up and running. Now, dear reader, let me tell you a tale of strangeness and charms.

Enter Juju

If you’re not familiar with Juju, I’d urge you to pay a visit to the Juju website to learn more, but in brief, I’ll explain: Juju is an orchestration service for Ubuntu. Using Juju allows you to deploy services rapidly, scaling up or down as you need. Each service is contained within a Charm, which is at it simplest a set of scripts that ensure that a given Juju unit does what it’s supposed to do at the appointed time (for example: install and config_changed are two of the most common hook scripts for a charm to have). We realised that in order to make our life simpler when testing our parallelisation work we could develop a pair of Buildbot Charms (one for the master, one for the slave) which when deployed through Juju, and given the right set of configuration options, would give us a working Buildbot setup on which to test Launchpad.

More about the charms…

The charms need to be able to automatically configure themselves to talk to each other (this is usually managed in Buildbot by static configuration files). Luckily, Juju provides for exactly that situation with the notion of “relations”; one charm can declare that it provides a particular interface as part of a relation and another can say that it requires that interface in order to be able to be a part of that relation. For our Buildbot charms, we have the following in the master’s metadata.yaml:

provides:
  buildbot:
    interface: master

And in the slave:

provides:
  buildbot:
    interface: slave
requires:
  buildbot:
    interface: master

Each charm has a couple of hooks that deal with relation, named in the form buildbot-relation-* where * is joined, changed or broken. These are run by Juju at the appropriate point in the process of connecting one instance to another. With all this in place, then, we can set up a working Buildbot environment by doing something like this:

$ juju bootstrap # create the Juju environment
$ juju deploy buildbot-master —config=/path/to/master/config.yaml # deploy the master charm
$ juju deploy buildbot-slave —config=/path/to/slave/config.yaml # deploy the slave charm
$ juju add-relation buildbot-slave buildbot-master

The last line – juju add-relation buildbot-slave buildbot-master– tells Juju to connect the buildbot slave node to the master node. The two then do a bit of a dance to configure each other properly (in fact, it’s mostly a case of the slave saying: “Hey, I’m here, what do you want me to do?” and the master passing back configuration instructions). Once this is all done, you have a working Buildbot master and slave, ready to accept work to build.

What have we discovered about Juju?

First and foremost, we’ve learned just how powerful Juju actually is. We’ve taken a fairly complex-to-configure build environment, for which we normally use dedicated machinery whose configuration is not to be touched without sysadmin blessing on pain of pain, and turned it into something that we can deploy with four or five commands and a couple of configuration files. Sure, Juju has its quirks and oddnesses, but when we’ve run across them the Juju development team has been amazingly helpful with workarounds or, more usually, bug fixes. The current version of Juju is implemented in Python, too, so we find it pretty easy to contribute fixes of our own if we need to.

Where can I find out more?

As I said above, if you want to know more about Juju, you can check out the Juju website. If you want to take a look at our Buildbot charms and how we’ve built our hooks (they’re written in Python because that happens to be our language of choice, but in fact they can be written in anything so long as they’re executable), you can grab our code from Launchpad:

• For the master: bzr branch lp:~yellow/charms/oneiric/buildbot-master/trunk buildbot-master
• For the slave: bzr branch lp:~yellow/charms/oneiric/buildbot-slave/trunk buildbot-slave

If you’ve got questions about Juju in general, the folks in #juju on Freenode are always tremendously helpful. If you’ve got any questions about our charms, ask them in the comments here and I’ll do my best to answer them.

((Image by http://www.samcatchesides.com/ under a Creative Commons license)

Benji’s blog post earlier this week gave you all some insight into what the Launchpad Yellow Squad has been doing recently in its attempt to parallelise the Launchpad test suite. One of the side effects of this is that we’ve been making quite a lot of use of Juju, and we thought it’d be nice to actually spell out what we’ve been doing.

The problem

We’re working to parallelise Launchpad’s test suite so that it doesn’t take approximately one epoch to get a branch from being approved for merging until it lands. A lofty goal, sure, and one that presents some interesting problems from the perspective of building an environment to test our work in. You see, Launchpad’s build infrastructure is a pretty complicated beast. It’s come a long way since the time when submitting a branch for merging meant sending an email to our PQM bot, which would then run the test suite and kick the branch out if it failed, but now it’s something of a behemoth.

Time for some S&M

We use Buildbot as our continuous integration system. There are two parts to Buildbot: the master and the slave. Broadly put, the slave is the part of Buildbot that is responsible for doing the actual work of compilation and running tests and the master is responsible for telling the slave when to do things. Each master can be responsible for several slaves. When it became obvious that we were going to need to essentially replicate our existing setup in order to test our parallelisation work, we considered asking Canonicals system administrators, in our sweetest tones, to give us a box upon which to do our testing work, but we spotted two reasons that this would be problematic:

1. We didn’t actually know at the outset what the best architecture was for our project.
2. Asking for a machine without knowing what you actually need is likely to earn you a look so old it could have come from an ammonite, at least if you have sensible sysadmins.

So instead, the obvious solution: use Amazon EC2. After all, that would allow us to play with different architectures without there being any huge cost in terms of physical resources. Moreover, we’d be able to have root access on the instances on which we were testing, which makes debugging such a complicated process so much easier.

However…

There was still a problem. How to actually set up the test instances, given that there are five of us spread between three timezones, that it takes a significant amount of time to set up a machine for Launchpad development, and finally that we don’t really want to leave EC2 instances running overnight if we don’t have to (because it’s expensive).

The sequence of steps we’d have to take to up an instance tends to look something like this:

1. Launch a new EC2 instance (this happens pretty quickly, thanks, Amazon)
2. Make sure that everyone’s public SSH keys are usable on that instance
3. Run our Launchpad setup script(s) (this takes about an hour, usually).
4. Install buildbot.
5. Configure buildbot correctly as   master or slave.
6. Run buildbot (or buildslave, if this is a slave) and make sure it’s hooked up correctly to the other type of buildbot.
7. Get some code into buildbot and make it run the test suite.

Launchpad has a lot of tests, almost 20,000. There are tests that make sure the internals work as expected, that verify the Javascript works in web browsers, and everything in between. In a perfect world those tests would only take seconds to run. In this world they take hours; six hours on our current continuous integration machines, for instance.

These long-running tests severely impact the time it takes to develop and deploy changes to Launchpad. We would like to improve the situation.

Given that the test cases are theoretically independent of one another, the obvious thing to do is to run the tests in parallel on a multi-core machine. Unfortunately many of the tests interact with the environment (databases, memcached, temporary directories, etc.) and conflict if run simultaneously.

Enter LXC

What we need is a way to isolate the test processes from each another. Virtual machines would allow us to do that, but the overhead and heavy-weight setup makes them unappealing. That’s where LXC (Linux Containers) comes in handy. LXC

allows the easy creation of “containers” that are isolated from the “host” machine without the performance overhead of VMs.

For example, to create a new container use lxc-create:

lxc-create -n test -t ubuntu

The container can then be started:

lxc-start -n test -d

And we can connect to it via SSH (using the default username and password shown during creation, if applicable):

ssh ubuntu@test

There are many options for customising the containers, including mounting a portion of the host’s file system in the container so sharing files between the two is easy.

Getting Ephemeral

All this is very nice for running isolated, parallel test runs but setting up and managing eight or more containers (one per core) is
off-putting, so we have used (and improved) a new LXC feature, “ephemeral” containers (created with lxc-start-ephemeral).

Ephemeral containers are “clones” of a base container and can have a temporary file system that reflects the contents of the base container but any writes are stored in-memory and are not written to disk. This allows us to install Launchpad on a single base container and then spawn many ephemeral containers, each with their own list of tests to run.

The ephemeral containers can then write to their local file systems without interfering with the others running simultaneously. The
containers may also benefit from faster IO because of the file system changes being stored in memory.

Results

We are still working out the kinks in our approach and wrestling with the occasional LXC bug as well as bugs in the Launchpad test suite itself. Even so we have already shortened a full test run on an eight-core EC2 instance down to 45 minutes; a substantial improvement over the current six hours.

(Image by Tolka Rova, Creative Commons license)

One of the main obstacles I come across when putting forward ideas for user testing for a project, is time:

“We’re on a very tight deadline, we can’t fit in testing,” “Can we leave it until the next release? There isn’t enough time at the moment.” “We just haven’t added in the time for all that user testing stuff.”

But the good news is – there is always time.

User testing, or usability testing (which is what we should really call it as we’re testing if things are usable, not testing the users themselves) can be extremely flexible. It can range from a detailed study of hundreds of painstakingly selected users, conducted in specially constructed labs with hidden screens, video recording devices and microphones, costing thousands of credits, with months to analyse and report the results. On the other end of the scale, it can simply be asking someone you pass in the corridor to look at a quick sketch of a wireframe you’ve made on the back of a napkin.

User testing can be both of these things, and everything in between, and yes, this can depend on time, and of course the other buzzword that sits so closely next to it – money. The thing is, it’s always better to do something, rather than nothing, however tight a deadline is – even if that is just asking a few users to try out a particular feature or function that you’re developing – whether this be with a flat mock-up or a working prototype.

Setting up some basic tests with a handful of users, running them and then writing up the results doesn’t need to take more than a day or two. The results will be pretty simple, and depending on the tests, will more likely be useful as a sense-check than a source of detailed information on user behaviour or working patterns, but  this is still valuable stuff that can make or break a new feature. The results will broadly have one of three outcomes – user’s just didn’t ‘get it’ and there are big problems to be fixed; there are smaller problem’s that have slipped everyone’s mind but the user’s found fairly quickly; or (rarely, almost never) everything was perfect and the users had a seamless, faultless experience.

After I’ve reached this point in the discussion, I sometimes come across another potential user research blocker…

“But there’s no point in finding this out, we don’t have enough time to change things before our deadline.”

It may be true that there’s no time to redesign a feature based on recommendations from user testing results in your current cycle – but it’s better to go into the next phase of a project already knowing at least a bit about what user’s think. If you’re in the final stage of a project, these kind of problems can be treated as bugs and ticked off one at a time.

It’s easy to become blinkered with a project, working with the same concepts, terminology and use patterns day after day – it can become hard to think – “if I was looking at all this stuff for the first time, would it make sense?” User testing in its quickest and simplest form aims to answer this question. And that’s something there’s always time for.

Dan: What’s your role on the Launchpad team?

Laura: I’m the Launchpad Support Specialist, so my job is pretty varied each day. Launchpad is rather larger than I first ever thought or had experience in using but it’s great to see so many people use it on a daily basis.

My role is to help people via email or IRC with their queries or point them in the right direction of where they can get more information or submit a bug or help them achieve something. I also look after Launchpad bugs and questions each day and it’s fascinating to see the varying questions we get on there so it’s a great way to learn and also see what interesting projects are on Launchpad and the communities that use it.

Dan: You’ve been working on Launchpad as a community member for a while though yeah?

I’ve been using it in the Ubuntu community in the past for blueprints, reporting bugs and and tracking issues and the odd time if I can help out in translations.

Dan: What’s been the biggest challenge in your new role so far?

Laura: Bazaar and PPAs both of which are bizarre to me at present, but the folks in the Launchpad and Bazaar teams have been really helpful to me and really made working with them easy.

Dan: Where do you work, and what can you see from your window?

Laura: I live in London, and work from home four days a week so when I look out the window I see the reflection of the London Eye. The other day a week I head into Canonical HQ.

Dan: If time/money was not an issue, what would you change about Launchpad?

Laura: Oh I’d love to make Launchpad translatable as I do know many people who love to get more involved, having it translated would help here. I’d also love to get more of the developer community involved in Launchpad, and where Launchpad isn’t doing what they’d like get them to submit patches and get them more involved in the process. It’s open source after all 🙂

Dan: How did you first start to get involved in the open source community?

Laura:I got involved when I was in college where I was roped into joining our computer society Skynet. Soon I became treasurer and event organiser and then eventually president of the society and got involved running open source conferences. Never looked back since!

We are reimagining the nature of privacy in Launchpad. The goal of the disclosure feature is to introduce true private projects, and we are reconciling the contradictory implementations of privacy in bugs and branches.

We are adding a new kind of privacy called “Proprietary” which will work differently than the current forms of privacy.

The information in proprietary data is not shared between projects. The conversations, client, customer, partner, company, and organisation data are held in confidence. proprietary information is unlikely to every be made public.

Many projects currently have private bugs and branches because they contain proprietary information. We expect to change these bugs from generic private to proprietary. We know that private bugs and branches that belong to projects that have only a proprietary license are intended to be proprietary. We will not change bugs that are public, described as security, or are shared with another project.

This point is a subtle change from what I have spoken and written previously. We are not changing the current forms of privacy. We do not assume that all private things are proprietary. We are adding a new kind of privacy that cannot be shared with other projects to ensure the information is not disclosed.

Launchpad currently permits projects to have default private bugs and branches. These features exist for proprietary projects. We will change the APIs to clarify this. eg:

    project.private_bugs = True  => project.default_proprietary_bugs = True
    project.setBranchVisibilityTeamPolicy(FORBIDDEN) => project.default_proprietary_branches = True

Projects with commercial subscriptions will get the “proprietary” classification. Project contributors will be able to classify their bugs and branches as proprietary. The maintainers will be able to enable default proprietary bugs and branches.

Next part: Launchpad will use policies instead of roles to govern who has access to a kind of privacy.

We are reimagining the nature of privacy in Launchpad. The goal of the disclosure feature is to introduce true private projects, and we are reconciling the contradictory implementations of privacy in bugs and branches.

We must change the UI to accommodate the a kind of privacy, and we must change some existing terms because to avoid confusion.

We currently have two checkboxes, Private and Security that create 4 combined states:

• Public
• Public Security
• Private Security
• Private something else

Most private bugs in Launchpad are private because they contain user data. You might think at first that something that is just private is proprietary. This is not the so. Ubuntu took advantage of defects in Launchpad’s conflation of subscription and access to address a kind of privacy we did not plan for. Most private bugs in Launchpad are owned by Ubuntu. They were created by the apport bug reporting process and may contain personal user data. These bugs cannot be made public until they are redacted or purged of user data. We reviewed a sample of private bugs that belong to public projects and discovered more than 90% were made private because they contained user data. Since project contributors cannot hide or edit bug comments, they chose to make the bug private to protect the user. Well done. Launchpad needs to clarify when something contains user data so that everyone knows that it cannot
be made public without removing the personal information.

Public and private security bugs represent two states in a workflow. The goal of every security bug is to be resolved, then made public so that users are informed. People who work on these issues do not use “public” and “private”, they use “unembargoed” and “embargoed”.

Also, when I view something that is private, Launchpad needs to tell me why. The red privacy banner shown on Launchpad pages must tell me why something is private. Is it because the page contains user data, proprietary information, or an embargoed security issue? This informs me if the thing could become public.

When I want to change somethings visibility, I expect Launchpad to show me a choice that clearly states my options. Launchpad’s pickers currently shows me a term without an explanation, yet Launchpad’s code does contain the term’s definition. Instead of making me search help.launchpad.net (in vain), the picker must inform me. Given the risks of disclosing personal user data or proprietary information, I think an informative picker is essential. I expect to see something like this when I open the visibility picker for a bug:

Branches require a similar, if not identical way of describing their kind of information. I am not certain branches contain user data, but if one did, it would be clear that the branch should not be visible to everyone and should not be merged until the user data is removed.

Next post: We are adding a new kind of privacy called “Proprietary” which will work differently than the current forms of privacy.