While working with action_trigger_aggregator.pl I tried to pull a single day's events by setting --start-date and --end-date to the same value. This resulted in nothing because a bare date in postgresql just has 00:00:00 tacked on the end so it's looking for events with a date >= '2017-10-28 00:00:00' and < '2017-10-28 00:00:00' which is of course 0 events. While you can manage this after realizing your mistake (and doing date math in your scripts, ick) I wonder if it would be better to make the end-date inclusive by manually appending 24:00:00 (this is a valid value, and handy) to the value or adding another parameter called just --date that handles all of this internally in whatever way. I thought I'd get some opinions rather than just throwing patches around (I personally like the 24:00:00 method because in my mind I want the dates to be inclusive, not left-inclusive - right-exclusive).
I'd prefer a --date (or better yet --duration) option to appending a day to --end-date.
I would also caution against using "24:00:00" as a duration when "1 day" will work, since the former is not DST-friendly.