Does anyone know of an ASCII representation for timestamps, similar to ISO8601, but that sorts in reverse order? Long form: @Yoni Augarten and I are working on improving usability of run_id in GC. Currently in order to discover which run_id to provide to a run, you pretty much need a KV store to keep the last few run_ids by time. That's an ops problem. As a first step we want to change the format of run_ids to be sort -- so instead of

<UUID>

we will use something like

<TS_ISO_8601>-<RANDOM>

. Now the files

.../retention/gc/commits/run_id.../commits.csv

will list in time-sorted order. So no need for KV, we can simply list these objects in S3. Unfortunately, it is still hard to go backwards in such a list. And that's actually the preferred mode: "find the last run_id from at least 2 weeks ago". So... I'd really like to name them

<REVERSE_8601_ISH>-<TS_ISO_8601>-<RANDOM

, where RANDOM_8601_ISH is an ISO 8601-like printable representation of timestamp that sorts in reverse order, and we include TS_ISO_8601 merely for readability. Now we just need an encoding 🙂 Where I've gotten so far: use a 9s-complement ASCII representation. An even less-readable representation would use e.g.

10000000000 - EPOCH

(right now would be

8337539453

(== 10000000000-1662460547), and 5 seconds later it would be

8337539448

. A more-readable representation might use

<10000-YYYY>-<100-mm>-<100-DD>N<100-HH>:<100-MM>:<100-SS>

, and let you decode in your head with a little effort. Is there any more standard way to do this?