Currently, `omdb` formats `chrono::DateTime`s using the default
`fmt::Display` format. This uses a bunch of characters of line width,
which becomes important for `omdb` commands which output tabular data
with a large number of columns --- avoiding line wrapping wherever
possible makes it substantially easier to read such output. @iximeow
pointed out to me that we could save several characters of line width
by using a more concise timestamp format.
This commit changes tabular output in `omdb db` commands to format
timestamps using `chrono`'s RFC 3339 formatter with millisecond
precision, rather than nanosecond precision. This saves us a few
characters. RFC 3339 permits the use of `Z` rather than `+00:00` (the
UTC offset) for UTC timestamps, and since all our timestamps are UTC,
that saves us another four characters (also relative to the default
format, which uses ` UTC ` for UTC timestamps). Together, this makes
timestamp columns substantially shorter in `omdb db` output.
For example, consider `omdb db region-replacement list`:
```console
root@oxz_switch1:~# omdb db region-replacement list
note: database URL not specified. Will search DNS.
note: (override with --db-url or OMDB_DB_URL)
note: using DNS server for subnet fd00:1122:3344::/48
note: (if this is not right, use --dns-server to specify an alternate DNS server)
note: using database URL postgresql://root@[fd00:1122:3344:109::3]:32221,[fd00:1122:3344:105::3]:32221,[fd00:1122:3344:10b::3]:32221,[fd00:1122:3344:107::3]:32221,[fd00:1122:3344:108::3]:32221/omicron?sslmode=disable
WARN: found schema version 110.0.0, expected 111.0.0
It's possible the database is running a version that's different from what this
tool understands. This may result in errors or incorrect output.
Region replacement requests
ID REQUEST_TIME REPLACEMENT_STATE
07a289e6-af50-42f1-8888-062229547888 2024-08-14 19:43:13.318246 UTC Complete
08c449a6-25c1-46f8-b070-9223cb924cb0 2024-08-14 19:43:13.245003 UTC Complete
1ed5e8e1-1d98-4420-bef0-135cba510238 2024-08-14 19:43:13.227734 UTC Complete
20811f9d-f6ed-40fe-8403-305edc4b3e8c 2024-08-14 19:43:13.291419 UTC Complete
52bd1034-2a77-4a17-8871-77e535b509d5 2024-08-14 19:43:13.259033 UTC Complete
5c43d936-d5c4-4d4e-b1ca-890aabeeae87 2024-08-14 19:43:13.357786 UTC Complete
915f8726-a882-4960-9e5c-dfe359f54911 2024-08-14 19:43:13.279 UTC Complete
a4e697b6-5f02-4f75-ad41-f5bc3e906f0b 2024-08-14 19:43:13.344742 UTC Complete
c2b5ef9d-a89a-46c8-b57e-1eebb5487804 2024-08-14 19:43:13.331527 UTC Complete
f0e009b5-1575-42f0-bca5-7df6db846ef0 2024-08-14 19:43:13.304655 UTC Complete
root@oxz_switch1:~# /var/tmp/omdb-eliza-test-concise db region-replacement list
note: database URL not specified. Will search DNS.
note: (override with --db-url or OMDB_DB_URL)
note: using DNS server for subnet fd00:1122:3344::/48
note: (if this is not right, use --dns-server to specify an alternate DNS server)
note: using database URL postgresql://root@[fd00:1122:3344:109::3]:32221,[fd00:1122:3344:105::3]:32221,[fd00:1122:3344:10b::3]:32221,[fd00:1122:3344:107::3]:32221,[fd00:1122:3344:108::3]:32221/omicron?sslmode=disable
WARN: found schema version 110.0.0, expected 111.0.0
It's possible the database is running a version that's different from what this
tool understands. This may result in errors or incorrect output.
Region replacement requests
ID REQUEST_TIME REPLACEMENT_STATE
07a289e6-af50-42f1-8888-062229547888 2024-08-14T19:43:13.318Z Complete
08c449a6-25c1-46f8-b070-9223cb924cb0 2024-08-14T19:43:13.245Z Complete
1ed5e8e1-1d98-4420-bef0-135cba510238 2024-08-14T19:43:13.227Z Complete
20811f9d-f6ed-40fe-8403-305edc4b3e8c 2024-08-14T19:43:13.291Z Complete
52bd1034-2a77-4a17-8871-77e535b509d5 2024-08-14T19:43:13.259Z Complete
5c43d936-d5c4-4d4e-b1ca-890aabeeae87 2024-08-14T19:43:13.357Z Complete
915f8726-a882-4960-9e5c-dfe359f54911 2024-08-14T19:43:13.279Z Complete
a4e697b6-5f02-4f75-ad41-f5bc3e906f0b 2024-08-14T19:43:13.344Z Complete
c2b5ef9d-a89a-46c8-b57e-1eebb5487804 2024-08-14T19:43:13.331Z Complete
f0e009b5-1575-42f0-bca5-7df6db846ef0 2024-08-14T19:43:13.304Z Complete
root@oxz_switch1:~#
```
Although the output from the `region-replacement list` command is not
*that* wide, I'm presently working on an instance VMM history command
that displays three timestamps, and the width saving becomes quite
significant there.