OptRequirement

Revision 14 as of 2012-04-16 14:41:00

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This page discusses the current state of the /opt requirement for apps.

Background

Apps which go to the AppReviewBoard, currently have the requirement to install files into /opt.

Rationale

  • Avoiding conflicts: Installing files into a separate location on the file system helps to avoid file conflicts.

  • (Future) confinement: In the future this would allow us to more easily confine apps.(?)

    • Currently possible already: through directory separation things like (broken) plugins are impossible to do.
  • FHS definition: /opt is for third-party vendors.

Previous discussion

Docs

Exceptions

Exceptions to the /opt requirement need approval by the TB on a case by case basis. Currently unity extensions and .desktop file are allowed.

Problems

  • Our toolkits, checking tools and frameworks are stream-lined to install files into /usr, not into /opt.
  • General documentation on the internet is all about /usr.
  • If you want to get your app into Ubuntu, you have to either special-case where you look for files or maintain separate versions of your code.
  • ARB spends vast majority of time educating, fixing and rejecting.

Solutions

  • A large number of possible conflicts could be avoided if we check package contents against:
    • $release Contents*.gz files (for stable releases they exist and don't change)
    • Contents*.gz files for -updates, -security and -backports, archive.canonical.com and extras (these would need to be generated).
    • One caveat would be diversions and alternatives, but they could be checked with a logic like in command-not-found.
    • An unlikely, but possible problem is: App A is accepted and ships file X, later on package B in Ubuntu proper ships new file X. Conflict!
      • Could this be avoided (or at least be made much less likely) with having a "no general-purpose file/directory name" policy?
  • Confinement is a problem not solved by the /opt requirement, but with initiatives like SecurityTeam/Specifications/Precise/AppArmorEasyprof be considered in the future.

    • Plugins such as Nautilus plugins are currently not allowed anyway. The /opt requirement just 'automatically' rules out they sneak in.