Design constraints

Building packages

• Building packages should not require any more than the Python standard library. In particular, it should not require dpkg, python-debian, or any other such Debian-specific tools.

  Rationale: We want people to be able to build Click packages easily on any platform (or at least any platform that can manage a Python installation, which is not too onerous a requirement).

Installing packages

• For the purpose of rapid prototyping, package installation is also implemented in Python. This may of course use Debian/Ubuntu-specific tools, since it will always be running on an Ubuntu system. In future, it will probably be re-implemented in C for performance.

• Reading the system dpkg database is forbidden. This is partly to ensure strict separation, and partly because the system dpkg database is large and therefore slow to read.

• Nothing should require root, although it may be acceptable to make use of root-only facilities if available (but remembering to pay attention to performance).