The TLDR is most lunar soil plus hydrogen and solar red heat gives a couple percent by mass oxygen in a couple hours.
So solar concentrators "boiling" vats of lunar dirt in the 14 day day, then tanks and nuclear powered LED illuminated plants during the 14 day night.
People don't use much oxygen by mass (although the volume is impressive) so a natural safety strategy is to melt chambers in the base so immense that you can survive a lunar night without any working O2 source. You'll want warehouse space to store "stuff" anyway.
On mars, a worst case scenario means you're a couple years away from the earth's surface (not just O2 or general environmental, but food and disease and sickness) whereas the moon is never more than a couple days from anywhere on earth. That's very convenient. I wonder how many years / decades moonies will "need" 100% lifeboat coverage like that. Eventually it'll make more sense to get self help from a neighboring colony than to abandon ship and fly back to earth.