Use osqueryd to update the Munki ConditionalItems.plist. You can run the binary as a munki preflight script. This utility assumes osquery is already running in your environment. To create queries for osqueryd to run, write them in a text file, one line per query. Your queries are expected to return key/value pairs as results. For example, select * from system_info; would return a list of key/values. When updating the ConditionalItems.plist file, all the keys will be prefixed with osquery_.