vracker  --  version tracker
============================

vracker is basically a set of scripts obtaining and presenting version
information in uniform way.


JSON output format
------------------

JSON returned from source script in vracker is a dictionary of
maintained versions, where key is the version number (without v prefix),
and value is an object with following properties:
- date:       YYYY-MM-DD date of the official release     -- mandatory
- src:        URL of the source (it's usually a tarball)  -- optional
- src_sign:   URL of the source PGP signature             -- optional
- bins:       list of URLs of the binaries                -- optional
- bins_sign:  list of URLs of the binaries PGP signatures -- optional
- relnotes:   URL of the release notes                    -- optional
- changelog:  URL of the log of the changes               -- optional
- stable:     state of the release                        -- optional

Release notes are meant for human consumption, while change log lists
all the changes, these visible to the users and those under the hood.
Nowadays projects rarely keep change log, because output of git/hg/...
log (or their web-driven equivalents) is available for free.
On the other hand not every project keeps release notes or NEWS file.


### Examples

Excerpt for Linux kernel:

    {
      "4.3.5": {
        "src": "https://www.kernel.org/pub/linux/kernel/v4.x/linux-4.3.5.tar.xz",
        "src_sign": "https://www.kernel.org/pub/linux/kernel/v4.x/linux-4.3.5.tar.sign",
        "changelog": "https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/?id=refs/tags/v4.3.5",
        "stable": true,
        "date": "2016-01-31"
      },
      ...
    }

Excerpt for git:

    {
      "2.7.1": {
        "date": "2016-02-06",
        "src": "https://www.kernel.org/pub/software/scm/git/git-2.7.1.tar.xz",
        "src_sign": "https://www.kernel.org/pub/software/scm/git/git-2.7.1.tar.sign",
        "relnotes": "https://git.kernel.org/cgit/git/git.git/plain/Documentation/RelNotes/2.7.1.txt",
        "changelog": "https://git.kernel.org/cgit/git/git.git/log/?h=v2.7.1"
      }
    }


Requirements
------------

- POSIX shell, e.g. [bash] [1].
- POSIX bc, e.g. [GNU bc] [2] -- arbitrary precision calculator.
- [curl] [3]                  -- tool to transfer data from or to a server.
- [html-xml-utils] [4]        -- utilities for manipulating HTML and XML files.
- [jq] [5]                    -- JSON processor (compiled w/ Oniguruma libary).
- POSIX sed, e.g. [GNU sed] [6] -- stream editor.
- [xmlstarlet] [7]            -- utilities for working with XML files.

  [1]: https://www.gnu.org/software/bash/
  [2]: https://www.gnu.org/software/bc/
  [3]: https://curl.haxx.se/
  [4]: https://www.w3.org/Tools/HTML-XML-utils/
  [5]: https://stedolan.github.io/jq/
  [6]: https://www.gnu.org/software/sed/
  [7]: http://xmlstar.sourceforge.net/