Launchpad 1.0 Public Beta

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Today we unveiled the Launchpad 1.0 User Interface, which has been in private beta for the last few months. As well as the improved visual appearance, there are a number of new features such as the ability to add your own branding to Launchpad pages associated with your project (for example, Ubuntu’s pages).

As mentioned in the press release, we’ve got two new high profile projects using us for bug tracking: The Zope 3 Project and The Silva Content Management System. As part of their migration, we imported all their old bug reports (for Zope 3, and for Silva). This was done using the same import process that we used for the SchoolTool import. Getting this process documented so that other projects can more easily switch to Launchpad is still on my todo list.

As Launchpad is a user of Zope 3 technology, it is great being able to provide the bug tracking infrastructure for the project. It should also make it easier to collaborate on bugs that affect both Launchpad and Zope.

SchoolTool Moves to Launchpad

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Recently, the SchoolTool project has migrated to Launchpad for their bug tracker.

We performed an import of all their previous bug reports using a new bug importer I wrote. This was the third Launchpad bug importer I’d written (the previous ones being for the Ubuntu Bugzilla import and a SourceForge importer), so I wanted this one to be the last. So the design of this importer was to have a simple XML format as an intermediate step. That way we only need to target the XML format to support a new bug tracker. This will also make it possible for projects to provide their bug data in a form we can consume for the cases where they want to migrate their bugs to Launchpad but Canonical doesn’t have the resources to do the migration.

For the SchoolTool migration, Jean-Fran├žois Roche put together a simple Roundup exporter.

We should have some documentation about the intermediate XML format available at some point for projects interested in moving to Launchpad.

UTC+9

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Daylight saving started yesterday: the first time since 1991/1992 summer for Western Australia. The legislation finally passed the upper house on 21st November (12 days before the transition date). The updated tzdata packages were released on 27th November (6 days before the transition). So far, there hasn’t been an updated package released for Ubuntu (see bug 72125).

One thing brought up in the Launchpad bug was that not all applications used the system /usr/share/zoneinfo time zone database. So other places that might need updating include:

  • Evolution has a database in /usr/share/evolution-data-server-$version/zoneinfo/ that is in iCalendar VTIMEZONE format.
  • Java has a database in /usr/lib/jvm/java-$version/jre/lib/zi. This uses a different binary file format.
  • pytz (used by Zope 3 and Launchpad among others) has a database consisting of generated Python source files for its database.

All the above rules time zone databases are based on the same source time zone information, but need to be updated individually and in different ways.

In a way, this is similar to the zlib security problems from a few years back: the same problem duplicated in many packages and needing to be fixed over and over again. Perhaps the solution is the same too: get rid of the duplication so that in future only one package needs updating.

As a start, I put together a patch to pytz so that it uses the same format binary time zone files as found in /usr/share/zoneinfo (bug 71227). This still means it has its own time zone database, but it goes a long way towards being able to share the system time zone database. It’d be nice if the other applications and libraries with their own databases could make similar changes.

For people using Windows, there is an update from Microsoft. Apparently you need to install one update now, and then a second update next year — I guess Windows doesn’t support multiple transition rules like Linux does. The page also lists a number of applications that will malfunction and not know about the daylight saving shift, so I guess that they have similar issues of some applications ignoring the system time zone database.

bzr branch https://launchpad.net/products/foo

One of the things we’ve been working on for Launchpad is good integration with Bazaar. Launchpad provides a way to register or host Bazaar branches, and nominate a Bazaar branch as representing a particular product series.

For each registered branch, there is a branch information page. This leads to a bit of confusion since Bazaar uses URLs to identify branches, so people try running bzr branch on a branch information page. We also get people trying to branch the product or product series pages.

There were two ways we could address this problem: (1) do more to encourage people not to do this, or (2) make bzr branch do what the user meant it to do. The second option is the more user friendly, so that’s what we chose. This just left the problem of how to implement it efficiently.

The obvious way to get this to work is with a simple HTTP redirect for files under the .bzr/ directory. Unfortunately this would result in Bazaar hitting the Launchpad webapp for every file in the branch which is not desirable (each request results in a number of database accesses, which would add unnecessary load to the system). There is a Bazaar bug about improving this so that it would use the new location after the first redirect. This bug was the main reason for not implementing the feature previously.

While playing around with things a bit, I realised that Bazaar already had the features needed to implement the redirects and they have been there since 0.8.

In Bazaar 0.8, the concept of a lightweight checkout was introduced. This is just a working tree plus a reference to a branch stored elsewhere. You can perform most operations on the branch from the checkout directory that you can do from the real branch directory. So what happens if you publish the “branch reference” part of a lightweight checkout on the web? It turns out that they work fine, so that’s what I used for launchpad.net.

So with the change in place, the following commands will all give you a copy of the Bazaar webserve plugin:

bzr branch http://bazaar.launchpad.net/~bzr/bzr-webserve/webserve-dev
bzr branch https://launchpad.net/people/bzr/+branch/bzr-webserve/webserve-dev
bzr branch https://launchpad.net/products/bzr-webserve/trunk
bzr branch https://launchpad.net/products/bzr-webserve

Furthermore, they will all record the http://bazaar.launchpad.net/ URL as the parent branch, so future bzr pull commands will go directly to the branch.

Microsummaries in Firefox 2

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One of the new features in Firefox 2 is Microsummaries, which essentially allows dynamic bookmark titles. This is useful when bookmarking volatile pages, since the title can reflect the current state of the document rather than the state when the bookmark was created.

The system works by registering XSLT transformations that generate a simple text string from the page content. The registrations are either done via a <link> element, or matched via regular expressions. The system is designed to target users (who can register their own microsummary generators), website owners (who can suggest a generator through a <link> tag) and 3rd parties (who can provide generators for other sites to users).

For Launchpad, I’d fall into the second category. It would be nice to provide microsummary generators for bug pages, so you’d get an indication of the status of the bug, plus an up to date bug title. Now while all this information is available in the page content, we can provide it in a much more efficient manner (if we know the user is only interested in generating a microsummary, why send them the 100 comments on the bug every time the bookmark title is to be updated?).

Being able to specify a transformation for the bookmarked URL that would be used instead for generating the summary would be one way of solving this. This would reduce the bandwidth requirements and processing time on our end. Another way would be for Firefox to include something in its request that would allow a site to know that the page was being retrieved for microsummary generation so it could ommit information.

Overall it looks like a useful feature, but I do wonder if it will suffer from the “RSS effect” and cause lots of needless traffic to web sites until people work out how to achieve the same effects in a less resource intensive fashion.