launchpadblog

Launchpad has quite a few background tasks that update things outside of your browser request, and the only way you know that they finished is to reload a page to see if it changes.

Updating the preview diff on a merge proposal is one example.

At our Launchpad sprint in Dublin a couple of weeks ago, we added a so-called “long poll” where the browser opens a long-running connection using XHR (a background Javascript connection) to a new piece of infrastructure called the “long poll server”

This server is something that the Landscape team originally wrote and we’ve now open-sourced it so we can use it in Launchpad. The server connects to a RabbitMQ instance and relays information back to the browser when the background task completes so that the user doesn’t need to keep reloading the page – the page will automatically update thanks to the magic of Javascript.

The proof-of-concept is done but we now need to make it work in our production environment, which means making it more reliable, configuring the deployment and add some stats collection so we can see how it behaves. We’ll start off by only letting a small subset of people use it and grow it over time until we consider it stable enough for all users.

Photo by Jay Gooby. Licence: CC BY 2.0

On Launchpad we have a lot of links that take your focus away from the current task. Usually, these exist to let you get more information on Launchpad or take you off Launchpad to do something like look at upstream information.

These links are usually represented one of two ways–a blue link with a globe for something that takes you to a new website, or a blue or green link for an internal link that opens a new window.

There’s a problem with this though. Green links mean an action will not take you away from your current view. Using a green link to take you to another window is a contradiction in our UI. Blue links alone aren’t ideal either, because blue links are scary. Everyone’s been bitten by clicking a link while in the process of filling out a form and losing the data they’ve spend five minutes filling out.

Right now, on our enhanced person-pickers, we have a green “Details…” link to let you see more information about a person. This link opens in a new tab, and we need to come up with a better way to indicate that action. We’ve put together a survey showing some rough ideas of how we might indicate a link that opens in a new window. It’s a very short survey, and we would love to get your input.

Please, take the “link opens a new window” survey.

We’re having a Launchpad meet-up in Dublin next Wednesday (29th June) from 8pm at the Porterhouse on Nassau Street.

Come and meet some of the Canonical Launchpad team, a few other Canonical types and members of the Ubuntu Irish LoCo.

We are testing changes to the person picker used on many pages in Launchpad. Our general goal is to ensure that you can trust you know who the user you are seeing is.

Beta testers will see two subtle changes to pages: The login status area in the upper right of the page will show both your display name and launchpad id.

We call this presentation unique-name. This is the same presentation that users will see when you post a comment.

When you read comments, you should know exactly who wrote it. There should be no confusion when there are many users with the same Launchpad display name. Launchpad users commonly have a single word display name, such as Tom, and it is not clear who wrote the what when there are comments from several users named Tom on a page.

Beta testers will will see substantial changes to the person picker. We want you to find the user you are searching listed in the first page of results. It is easy to confuse users of similar name and IRC nickname, and users often hide their email address. The listing must show enough information for you to confidently make a choice.

There will always be a link to choose yourself for any action where you are a legitimate choice. You should never need to search for yourself.

The search results are ordered by best match. Exact matches on Launchpad Id, email address, and IRC nicknames are shown first. Users who are active in Launchpad are shown next. Non active users are shown last.

The listing of users shows the unique-name. IRC nicknames were added, since it was common for users to search on them. Those who are active in the project you are working with are shown with the project’s badge to the right of their name. While users may have similar names and IRC nicknames, Their Launchpad Id is unique and their activity in Launchpad or your project is a strong indication who the user is. There will be cases where you want to see more details about the user before choosing, so the listing includes a link to see the user’s profile.

We are tracking person picker defects with the person-picker tag. If you find issues not already reported, add the person-picker tag to your new bug get them triaged quickly: https://bugs.launchpad.net/launchpad/+bugs?field.tag=person-picker

Yesterday, Jonathan Lange our Product Strategist announced that he was leaving Launchpad after four and a half year. The fact that he’s only leaving next door to work on the Ubuntu Developer Programme from within the Platform team is only a small comfort.

Before becoming Launchpad Product Strategist, Jonathan was known for adding support for source package branches to Launchpad. He became Strategist at about the same time I took the interim leadership of Launchpad. It will interesting to see how I manage without him!

He was instrumental in most of the process changes that happened to the team in the last two years. We can thanks Jonathan for bringing us the LEP process which make sure that we focus on the right things before starting coding, the Stakeholders process to make sure that we are working on the right thing. He also brought some clarity on what Launchpad was all about! Recently, he has been working on clarifying the feature development process, so that we can deliver polished changes on a regular cadence to users. I’m probably forgetting also a lot of other changes which his constant quest for improvements suggested to us in one way or another.

Oh, and we can thank him for making sure that we didn’t move on early from daily builds, improved bug subscriptions and other changes without the polish they have today. I (and I’m sure our users) thank you!

Whoever takes that role forward, will have big shoes to fill! If you are interested by the challenge, a job opening should be posted soon!

Thanks a lot Jonathan, it was a pleasure to work with you all these years! You’ll be missed. Good luck with your new project, but I’m glad to think that the future of Ubuntu Application Development is in excellent hands!

Photo by Robin Robokow. Licence: CC BY-NC-SA 2.0.

DRY is one of my watchwords. That’s “Don’t Repeat Yourself“, of course.

If you’re designing your page to work with-and-without JavaScript enabled, then you’ll likely be tempted to repeat some of the
user-interface text in the template and in the JavaScript file. Especially for text that appears only some of the time.

One alternative is to render that text all the time, and only show it some of the time. In Launchpad, you add the “unseen” class to text in order to hide it.

In YUI3, it’s easy to add or remove classes using Node.toggleClass(). For example:

foo.toggleClass('unseen', baz);

This adds the ‘unseen‘ class to foo when baz is true, and removes it when baz is false.

This approach means you don’t need to repeat the text. It means your HTML stays in an XHTML file, with all the syntax-highlighting and other tool support that implies. It makes it easier to live with the fact that Launchpad don’t have a hardcore templating system in JavaScript.

It doesn’t eliminate all issues. If the page needs to have more than one instance of the text, this approach doesn’t directly apply. However, it’s easy to imagine extending it by using a hidden copy as a prototype and copying it as needed.

One disadvantage is that testing becomes harder. With conditional rendering, you can just check whether the text is rendered. With conditional visibility, you need to check whether the text has the unseen class, which is harder. If plan to apply this technique, it’s best to start out using it, or else you’ll have to rewrite all your tests when you switch approaches.

Another issue is that you will probably need to leave placeholders. For example, one of our conditionally-rendered strings included a link to a branch. When there’s no assigned branch, that text must be hidden. When someone assigns the branch via AJAX, we need to have a placeholder for the branch link, so that we can set it to the correct value with Javascript. At present, there’s no way to generate placeholders for arbitrary types, so it must be done manually.

Launchpad has a nice feature for initialising on-page JavaScript, called the JSONCache. I recommend considering it as your first choice when writing JavaScript that needs to be initialised. The one downside is that due to bug #740208, it’s not available for users who aren’t logged in. But then, users who aren’t logged in don’t need a lot of JavaScript, because they can’t write to most of Launchpad.

I found out about the JSONCache when we were working on he sourcepackage +sharing-details pages recently. This JavaScript has model objects, but I didn’t know how we should initialise them. We considered initialising them from the page HTML. We considered using the web service. But it turned out there’s already a great facility for this: the JSON cache.

If you’ve hacked on Launchpad’s HTML, you probably already know that every you can get LP.cache.context and LP.cache.me from any Launchpad page. These come for free, but with a little more work, you can get any object you need:

        cache = IJSONRequestCache(self.request)
        cache.objects.update({
            'productseries': self.context.productseries,
            'upstream_branch': self.upstream_branch,
            'product': self.product,
        })

These entries will then appear in the LP.cache with the names specified in the dict.

However, they are provided as plain JavaScript mappings, unlike the values returned by lp.client.Launchpad. You can use convert_cache to create a copy of the cache containing lp.client.Entry values. This allows you to intermix values from the lp.cache and the web service freely.

convert_cache currently lives in translations/javascript/sourcepackage_sharing_details.js, but should probably be moved into lp.client.

One extension I’d love to see would be a way to retrieve an updated copy of just the JSONRequestCache for a page. That way, we could reduce our number of round-trips, and also be confident that everything was up-to-date.

I recently came back to JavaScript, having largely ignored it for a couple of years. Development in JavaScript is much nicer than I remember. I thought I should share what I’ve learned.

The first thing I’ll mention is YUI tests. If you’re a TDD developer (and if not, why not?), YUI unit tests are the way TDD should be. The change/test cycle is very fast (to run the tests, hit “reload” in your browser). And since they’re proper unit tests, they feel like a safety net when you start to make changes.

They are a good way to test your model code and HTML changes. Other members of the Launchpad team have used them to do more integration-style testing, as well. It’s somewhat difficult to set up I/O dependent tests, but that will encourage you to make most of your code I/O-independent.

For information on how to get started with them, see: Developing with YUI.Test

When I explained how we determined what feature to work on next, I mentioned that we were looking to add a stakeholders representative for the Ubuntu project. Well, it’s now done. The Ubuntu Technical Board delegated Bryce Harrington to that position.

So if you are part of the Ubuntu community and need something from Launchpad, you can now talk to Bryce.

I’m really glad to have him on that position. Not only is he a respected member of the Ubuntu community, but he also did a 6 months rotation within the Launchpad team, so has understanding of how our project operates.

He’ll now be in a position to escalate important bugs affecting the Ubuntu community, as well as present the community’s view on what new features should be prioritized. It won’t be an easy job, since the Ubuntu project is big and varied. The people who cares about bugs are often not the same that cares about translations nor the same that cares about package publishing or the Ubuntu distribution development toolchain. And the stakeholder representative job is to help prioritize these needs to make sure that the Launchpad team works on the most important work. Plus then he’ll have to find common grounds with the other stakeholder representatives!

Thanks Bryce for stepping up to these responsibilities!

Photo by Wally Gobetz. Licence: CC BY-NC-ND 2.0.

I’ve been asked this question privately a few times already. What does it mean for a squad to rotate from feature-mode to maintenance-mode? The question arises as a number of folks noticed that some members of the squad continue working on feature-related bugs after they are on maintenance shift. That happened with the former Blue squad when they completed daily builds, with the Orange squad when they completed sharing translations, and with the  Yellow squad and better bug subscriptions. So let me clarify what that boundary means.

In a nutshell, it means that the squad starts new work from a different queue. After the switch, new work will come from the general maintenance queue. Because we do the switch aligned with the calendar week, there is always work related to the feature that is still in-process (code started but not reviewed, or landed but not deployed, etc.) That’s the work that continues after the transition. After the rotation, the squad also becomes on the hook to cater for the user support duties related to maintenance mode.

What are the trade-off related to this boundary definition? The main impact is that we get a dip in maintenance related bug fixes around the rotation. That’s because the new maintenance squad has still some members not ready to start new maintenance-related work. It could be argued that because of the interrupt nature of the maintenance responsibilities, it would take longer to finish off the work related to the feature. I’m not sure that happens in practice, but I make note to check the data…

The alternative  would be to only rotate after all the feature-related bugs are done-done. The rest of the squad could fix some lower priority bugs related to the feature or clean-up tech-debt accumulated during their rotation.  It would preserve the number of people effectively working on maintenance around the transitions.  But it would mean that it would take longer before we start the next feature. And given the poor state of our feature cycle time, it’s not a trade-off that I (and I guess our stakeholders) would be willing to make at this time. We might revisit this in the future though.

Photo by Camilia Hoel. Licence: CC BY-NC-SA 2.0.