launchpadblog

Launchpad has had Git-to-Bazaar code imports since 2009, along with imports from a few other systems.  These form part of Launchpad’s original mission to keep track of free software, regardless of where it’s hosted.  They’re also very useful for automatically building other artifacts, such as source package recipes or snap packages, from code hosted elsewhere.  Unfortunately they’re quite complicated: they need to be able to do a full round-trip conversion of every revision from the other version control system, which has made it difficult to add support for Git features such as signed commits or submodules.  Once one of these features is present anywhere in the history of a branch, importing it to Bazaar becomes impossible.  This has been a headache for many users.

We can do better nowadays.  As of last year, we have direct Git hosting support in Launchpad, and we can already build snaps and recipes straight from Git, so we can fulfil our basic goal more robustly now with a lot less code.  So, Launchpad now supports Git-to-Git code imports, also known as Git mirroring.  You can use this to replace many uses of Git-to-Bazaar imports (note that there’s no translations integration yet, and of course you won’t be able to branch the resulting import using bzr).

See our Git documentation for more details.

We just rolled out a new feature for Launchpad’s Git repository hosting: Git-based merge proposals can now be linked to Launchpad bugs.  This can be done manually from the web UI for the merge proposal, but normally you should just mention the Launchpad bug in the commit message of one of the commits you want to merge.  The required commit message text to link to bugs #XXX and #YYY looks like this:

LP: #XXX, #YYY

This is the same form used for Launchpad bug references in debian/changelog files in source packages, and the general approach of mentioning bugs in commit messages is similar to that of various other hosting sites.

Bugs are not automatically closed when merge proposals land, because the policy for when that should happen varies from project to project: for example, projects often only close bugs when they make releases, or when their code is deployed to production sites.

Users familiar with Bazaar on Launchpad should note that the model for Git bug linking is slightly different: bugs are linked to merge proposals rather than to individual branches.  This difference is mainly because individual branches within a Git repository are often much more ephemeral than Bazaar branches.

Documentation is here, along with other details of Launchpad’s Git hosting.

Here’s what the Launchpad team did in October.

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If you are a member of Launchpad’s beta testers team, you can now try out webhooks for Bazaar branches and Git repositories. These can be used to set up integration with external sites for various purposes, such as running CI jobs or publishing documentation. We expect to open this up to all Launchpad users soon, but in the meantime please do file a bug against Launchpad itself if you encounter any problems.

See our webhooks documentation for more details.

Update: as of 2015-11-20, this feature is enabled for all Launchpad users.

Personal package archives on Launchpad only build for the amd64 and i386 architectures by default, which meets most people’s needs.  Anyone with an e-mail address can have a PPA, so they have to be securely virtualised, but that’s been feasible on x86 for a long time.  Dealing with the other architectures that Ubuntu supports (currently arm64, armhf, powerpc, and ppc64el) in a robust and scalable way has been harder.  Until recently, all of those architectures were handled either by running one builder per machine on bare metal, or in some cases by running builders on a small number of manually-maintained persistent virtual machines per physical machine.  Neither of those approaches scales to the level required to support PPAs, and we need to make sure that any malicious code run by a given build is strictly confined to that build.  (We support virtualised armhf PPAs, but only by using qemu-user-static in an amd64 virtual machine, which is very fragile and there are many builds that it simply can’t handle at all.)

We’ve been working with our sysadmins for several months to extend ScalingStack to non-x86 architectures, and at the start of Ubuntu’s 16.04 development cycle we were finally able to switch all ppc64el builds over to this system.  Rather than four builders, we now have 30, each of which is reset to a clean virtual machine instance between each build.  Since that’s more than enough to support Ubuntu’s needs, we’ve now “unrestricted” the architecture so that it can be used for PPAs as well, and PPA owners can enable it at will.  To do this, visit the main web page for your PPA (which will look something like “https://launchpad.net/~<person-name>/+archive/ubuntu/<ppa-name>”) and follow the “Change details” link; you’ll see a list of checkboxes under “Processors”, and you can enable or disable any that aren’t greyed out.  This also means that you can disable amd64 or i386 builds for your PPA if you want to.

We’re working to extend this to all the existing Ubuntu architectures at the moment.  arm64 is up and running but we’re still making sure it’s sufficiently robust; armhf will run on arm64 guests, and just needs a kernel patch to set its uname correctly; and powerpc builds will run in different guests on the same POWER8 compute nodes as ppc64el once we have suitable cloud images available.  We’ll post further announcements when further architectures are unrestricted.

October already! As the leaves start to turn red here in the northern hemisphere, here’s a brief summary of what we did in September.

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Here’s a summary of what the Launchpad team got up to in August.

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Here’s a summary of what the Launchpad team got up to in July.

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Users of some email clients, particularly Gmail, have long had a problem filtering mail from Launchpad effectively.  We put lots of useful information into our message headers so that heavy users of Launchpad can automatically filter email into different folders.  Unfortunately, Gmail and some other clients do not support filtering mail on arbitrary headers, only on message bodies and on certain pre-defined headers such as Subject.  Figuring out what to do about this has been tricky.  Space in the Subject line is at a premium – many clients will only show a certain number of characters at the start, and so inserting filtering tags at the start would crowd out other useful information, so we don’t want to do that; and in general we want to avoid burdening one group of users with workarounds for the benefit of another group because that doesn’t scale very well, so we had to approach this with some care.

As of our most recent code update, you’ll find a new setting on your “Change your personal details” page:

If you check “Include filtering information in email footers”, Launchpad will duplicate some information from message headers into the signature part (below the dash-dash-space line) of message bodies: any “X-Launchpad-Something: value” header will turn into a “Launchpad-Something: value” line in the footer.  Since it’s below the signature marker, it should be relatively unobtrusive, but is still searchable.  You can search or filter for these in Gmail by putting the key/value pair in double quotes, like this:

At the moment this only works for emails related to Bazaar branches, Git repositories, merge proposals, and build failures.  We intend to extend this to a few other categories soon, particularly bug mail and package upload notifications.  If you particularly need this feature to work for some other category of email sent by Launchpad, please file a bug to let us know.

It’s been a while since we posted much regularly on this team blog, not least because for a while Launchpad was running more or less in maintenance mode.  That’s no longer the case and we’re back to the point where we can do feature development work again, as exemplified by our recent addition of Git code hosting support.

Lots of other things have been happening in the Launchpad world lately, though, and the half-way point in the year seems like a good time to start talking about them.  I’m going to try to do this a bit more regularly, aiming for about once a month when we also update our internal stakeholders.  This post covers roughly the last three months.

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