usd has been renamed to git-ubuntu

After some internal bikeshedding, we decided to rework the tooling that the Server Team has been working on for git-based source package management. The old tool was usd (Ubuntu Server Dev), as it stemmed from a Canonical Server sprint in Barcelona last year. That name is confusing (acronyms that aren’t obvious are never good) and really the tooling had evolved to be a git wrapper.

So, we renamed everything to be git-ubuntu. Since git is awesome, that means git ubuntu also works as long as git-ubuntu is in your $PATH. The snap (previously usd-nacc) has been deprecated in favor of git-ubuntu (it still exists, but if you try to run, e.g., usd-nacc.usd you are told to install the git-ubuntu snap). To get it, use:

sudo snap install --classic git-ubuntu

We are working on some relatively big changes to the code-base to release next week:

  1. Empty directory support (LP: #1687057). My colleague Robie Basak implemented a workaround for upstream git not being able to represent empty directories.
  2. Standardizing (internal to the code) how the remote(s) work and what refspecs are used to fetch from them.

Along with those architectural changes, one big functional shift is to using git-config to store some metadata about the user (specifically, the Launchpad user name to use, in ~/.gitconfig) and the command used to create the repository (specifically, the source package name, in <dir>/.git/config). I think this actually ends up being quite clean from an end-user perspective, and it means our APIs and commands are easier to use, as we can just lookup this information from git-config when using an existing repository.

As always, the latest code is at: https://git.launchpad.net/usd-importer

[USD #1] Ubuntu Server Dev git Importer

This is the first in a series of posts about the Ubuntu Server Team’s git importer (usd). There is a lot to discuss: why it’s necessary, the algorithm, using the tooling for doing merges, using the tooling for contributing one-off fixes, etc. But for this post, I’m just going to give a quick overview of what’s available and will follow-up in future posts with those details.

The importer was first announced here and then a second announcement was made here. But both those posts are pretty out-of-date now… I have written a relatively current guide to merging which does talk about the tooling here, and much of that content will be re-covered in future blog posts.

The tooling is browse-able here and can be obtained via

git clone https://git.launchpad.net/usd-importer

This will provide a usd command in the local repository’s bin directory. That command resembles git as being the launching point for interacting with imported trees — both for importing them and for using them:

usage: usd [-h] [-P PARENTFILE] [-L PULLFILE]
 build|build-source|clone|import|merge|tag ...

Ubuntu Server Dev git tool

positional arguments:
 build|build-source|clone|import|merge|tag
 
 build - Build a usd-cloned tree with dpkg-buildpackage
 build-source - Build a source package and changes file
 clone - Clone package to a directory
 import - Update a launchpad git tree based upon the state of the Ubuntu and Debian archives
 merge - Given a usd-import'd tree, assist with an Ubuntu merge
 tag - Given a usd-import'd tree, tag a commit respecting DEP14

...

More information is available at https://wiki.ubuntu.com/UbuntuDevelopment/Merging/GitWorkflow.

You can run usd locally without arguments to view the full help.

Imported trees currently live here. This will probably change in the future as we work with the Launchpad team to integrate the functionality. As you can see, we have 411 repositories currently (as of this post) and that’s a consequence of having the importer running automatically. Every 20 minutes or so, the usd-cron script checks if there are any new publishes of source packages listed in usd-cron-packages.txt in Debian or Ubuntu and runs usd import on them, if so.

I think that’s enough for the first post! Just browsing the code and the imported trees is pretty interesting (running gitk on an imported repository gives you a very interesting visual of Ubuntu development). I’ll dig into details in the next post (probably of many).