Create tool to detect new and end-of-life distro versions

[jodh-intel]

We use particular releases of Linux distributions for both our CI system and for creating OBS packages for users.

We need a tool that can identify:

• when new versions of the distros we're using are soon to be released.
• when an existing release we're using is soon to go EOL (end of life).

The tool is of limited value if it tells us that a new release is available "today" - we need advance warning of an upcoming release.

The tool could either consume RSS feeds, or use some sort of polling (even if it's just looking at particular distros archives to detect new release/pre-release directories).

There is a very simple and elegant solution to the problem, but only for Ubuntu - distro-info:

• Setup:

  $ sudo apt-get install -y distro-info
  $ date --iso-8601
  2018-01-18
  

• Number of days until the next Ubuntu release

  $ distro-info --fullname --devel --days=release
  Ubuntu 18.04 LTS "Bionic Beaver" 98
  $ date -d 'today + 98 days' --iso-8601
  2018-04-26
  

• Number of days until the current LTS release goes EOL

  $ distro-info --fullname --lts --days=eol
  Ubuntu 16.04 LTS "Xenial Xerus" 1189
  $ date -d 'today + 1189 days' --iso-8601
  2021-04-21
  

• Number of days until the current distro version goes EOL

  $ lsb_release -cs
  artful
  $ distro-info --series=$(lsb_release -cs) --days=eol
  182
  $ date -d 'today + 182 days' --iso-8601
  2018-07-19 
  

I think that we should add a CI check for Ubuntu using distro-info as it's exactly what we need, and consider how best to handle the other distros.

See also:

• https://github.com/clearcontainers/runtime/wiki/Handling-new-and-end-of-life-distro-versions
• Create tool to check for new LTS kernel releases packaging#246 (new + EOL LTS kernel versions)