| Ha, funny you should ask... I've started a project about a month ago that will apply various "rules" be applied to unique resource instances. (Sorry, I'm being explicitly vague as there are IP concerns here.) Here are some approaches that I find myself gravitating towards with this project (but still in design/early dev, and much more to address before this part): 1. Tag-based attributes for resources (as in "meta-data"). Tag combinations can be leveraged to apply specific "rules". But the interpretation of those tags won't be a jump-table or vector-table. If I can't see the domain I'm debugging, neither will the devs who come after me! 2. Taxonomies suck for this kind of thing. Ontologies (what I see as Taxonomies with links) may be required in extreme cases, but just make sure that the full path is always "visible", not just a pointer to node a in the ontology graph. The project I did work on for some time was usurped by another that grabbed my attention (I was re-assigned). Too bad, I didn't get to follow this through. I don't think this is needed for my current project, but time will tell. (I hope not, as it's "elegant" but not at all "simple") 3. State tracking automata may be possible as well. Each request to execute rules stores the path through the rule set directly within the request. Easy debugging and visibility. I've not implemented this type of "rule" system before, but I'd like to give it a shot some day. Of course, writing rule paths is time consuming (even if in-memory) and may be overkill. 4. One (simple) example of a rules engine is a command-line tool's argument parser. Does anyone store this data in a jump-table? I don't think so, (maybe GIT or AWS-CLI, but I don't know as I've not looked yet). Most solutions have a parse pre-step and then a current-state result, usually followed by a "switchboard" type rule applier. But, that state is usually always available; I think that simplicity. In short, for a given set of "attributes" which drive a "policy", I'd prefer to see the code rolled-out and explicit rather than deferring to some dance between a set of "rule tables" and a set of classes that get invoked in "special" ways. Of course, I know nothing of your domain; so please take this all with a grain of salt. I've not worked with more than several dozens of "rule sets" before; you may be facing 1000's (and it sounds like speed is critical for you as well). Your rules may be transient, time sensitive and possibly even self-modifying (ugh!). If so, I'd make certain that the path through the rule-sets (if truly required) are well documented and verbose in their logging. |