ref: 3bb5168c6f21b38e5b4415419f986b4fa466cbd9
dir: /sys/src/cmd/python/Tools/versioncheck/README/
This is versioncheck 1.0, a first stab at automatic checking of versions of Python extension packages installed on your system. The basic idea is that each package contains a _checkversion.py somewhere, probably at the root level of the package. In addition, each package maintainer makes a file available on the net, through ftp or http, which contains the version number of the most recent distribution and some readable text explaining the differences with previous versions, where to download the package, etc. The checkversions.py script walks through the installed Python tree (or through a tree of choice), and runs each _checkversion.py script. These scripts retrieve the current-version file over the net, compares version numbers and tells the user about new versions of packages available. A boilerplate for the _checkversion.py file can be found here. Replace package name, version and the URL of the version-check file and put it in your distribution. In stead of a single URL you can also specify a list of URLs. Each of these will be checked in order until one is available, this is handy for distributions that live in multiple places. Put the primary distribution site (the most up-to-date site) before others. The script is executed with execfile(), not imported, and the current directory is the checkversion directory, so be careful with globals, importing, etc. The version-check file consists of an rfc822-style header followed by plaintext. The only header field checked currently is 'Current-Version:', which should contain te current version and is matched against the string contained in the _checkversion.py script. The rest of the file is human-readable text and presented to the user if there is a version mismatch. It should contain at the very least a URL of either the current distribution or a webpage describing it. Pycheckversion.py is the module that does the actual checking of versions. It should be fine where it is, it is imported by checkversion before anything else is done, but if imports fail you may want to move it to somewhere along sys.path. Jack Jansen, CWI, 23-Dec-97. <jack@cwi.nl>