Thursday, February 03, 2011

Package Management & Workflow

For those who don't know, one of my "mini-projects" (of which there are many!) on the Pedigree project is the 'pup' package manager. The idea behind pup is to create a Python-oriented package manager that works great on Pedigree but can also be used for any other operating system that happens to have Python ported. Essentially all of the backend is just standard HTTP GET requests, the packages are just .tar.gz files, and building a package is dead simple (assuming the environment is okay).

The problem with 'pup' is that it current works out of a git repository which holds every package that will be in a master repository. This is great for editing the build scripts and versioning the pup source code, but when it comes to any form of management it's a nightmare. The solution for this is to write a web-based user interface for managing a package repository.

That's where it gets exciting.

Actually managing packages in their built state is very, very easy. You simply modify the SQLite database containing package information where necessary, and move the package files around. The difficulty comes from building and creating packages. The easiest way to convince users to port more software to Pedigree is to make it extremely easy to - this is the goal of pup and the build scripts in our Pedigree-Apps repository. So any web interface for management has to handle both managing existing packages (update/remove/rename/edit attributes) as well as handle bringing new packages into the system.

The workflow I came up with in my head for this is as follows:

  1. User creates a build.sh and related scripts to build the relevant port. This is hopefully tested by the user and works on that system. Creating these scripts is already documented.
  2. These scripts are uploaded to the web interface
  3. The permissions of the user are checked; depending on these the package will be automatically built on the server straight away, or added to a queue for moderation (we'll assume it was permitted to be built here).
  4. As the build continues, its status is made available to the user.
  5. Once the build completes, the user is notified of the status of the build. Most likely an IRC bot is also present to notify developers/interested parties of the build status.
  6. The package is added to the system and mirrored from the master repository to various other mirrors, ready for users to download the update/new package via pup on their Pedigree installation.
Here's the problem - as far as I can tell nothing like this exists.

So I'm looking at writing this myself, most likely in Python. It should be a fun project for when all the other projects are hitting dead ends, and has the added bonus of reducing my workload on Pedigree when done!

As an aside, notable changes since the last blog post:
  • We released a feature-test release - Foster Milestone #1.
  • SSE in the kernel, oh my! memset takes this very well, memcpy not so much due to floating point state issues. These are being resolved at the moment.
  • A variety of changes across the POSIX subsystem and within the network stack for improved stability.
Also, We're looking for anyone who's got a few year's worth of OS development under their belt to come on board and work on the project - if you feel like something new and a C++ kernel doesn't worry you, find us in #pedigree on Freenode IRC.

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