update-hash is a tool to assist software release developers in the management of buildout.hash.cfg files.
A lot of recipes which uses hashing for referenced files. Updating the hash results in part uninstallation and installation, which is desired behaviour, as the file might have to be redownloaded. By using update-hash with buildout.hash.cfg the developer does not have to do the calculations and updates manually, just calling the tool is enough.
Generally each Buildout profile which references some file shall use this approach to improve development process and minimise risk of using incorrect data from such entires.
buildout.hash.cfg files are buildout-style simplified configparser files to have a easy way to update MD5 hashes of provided files for download. They look like:
[section] md5sum = <hash> filename = <relative-path>
Where <hash> is an automatically calculated checksum of <relative-path>.
Then buildout.hash.cfg can be included in software profile by extends of [buildout] section, and the section's md5sum and filename can be used.
In case if section recipe has special unwanted behaviour for filename field the _update_hash_filename_ key can be used like:
[section] md5sum = <hash> _update_hash_filename_ = <relative-path>
In order to update the buildout.hash.cfg one just need to call update-hash while being in the directory containing the file.