akesterson / defunct-disco Goto Github PK

This is a fairly standard pattern in sorted CI engines. Currently we only have the ability to say "I require module XYZ before I execute". It would be useful to say "I MUST occur before module XYZ". This is simpler than the puppet approach (and arguably less effective), since you can only reference modules, and not individual resources; but it would bridge an important gap, nonetheless.

Consider if there is a "nfs_home_directory" ball; you may need to ensure that some custom stuff happens before nfs_home_directory gets used, but you can't modify nfs_home_directory, because the disco ball exists upstream and you don't maintain it. So instead of having a requires file that justs lists other disco nballs that you should come after, it could look like this:

before nfs_home_directory
after some_other_module

... the mechanism for this could be that, once the client has downloaded all modules, it modifies the 'requires' file of each 'before' module, to insert the requisite modules. Or perhaps something else. Either way, the topological sort would require a little bit of somewhat creative modification.