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.(?)

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.

Solutions

• Conflicts could be easily avoided if we check package contents against:
  • $release Contents*.gz files (for stable releases that's even easier)
  • Contents*.gz files for backports, archive.canonical.com and extras
  • One caveat would be diversions and alternatives, but they could be checked with a logic like in command-not-found.

• Confinement is a problem not solved by the /opt requirement, but with initiatives like SecurityTeam/Specifications/Precise/AppArmorEasyprof be considered in the future.