Use ISO8601 extended format with time zone for log timestamps

[altendky]

https://en.wikipedia.org/wiki/ISO_8601

Existing: 2021-10-16T22:50:30.453 full_node full_node_server        : INFO
New     : 2021-10-16T22:49:25.210-04:00 full_node full_node_server        : INFO

Closes https://github.com/Chia-Network/chia-blockchain/issues/8802.

[altendky]

I went ahead and made the code, but I don't know how much we want to consider backwards compatibility for log-parsing tools with this sort of change. Also, this makes the code slightly more complicated, which isn't a big deal, but if we were willing to have microseconds instead of milliseconds I think it would actually make the new code a bit simpler than the original. Also I'll note that https://en.wikipedia.org/wiki/ISO_8601 seems to suggest that there... was a preference for a , fractional separator. Or maybe still is "within International Standards", whatever exactly that means. As coded, it still uses a ..

[arvidn]

I would think a better direction to go in would be to print the date every time it changes, and on other log lines only include the 24 hour wall clock time (without date). A large portion of the screen space is wasted on repeating the same date over and over again now, when looking at logs.

[arvidn]

the time zone doesn't change either, so it seems quite unnecessary to print it on every line

[emlowe]

Not printing it on every line does defeat the original purpose of the change though - which is to support streaming the logs to some log ingester like grafana (#8802) - which presumably needs each line to be completely self-contained.

It's fairly typical to either include the timezone on the line (Common Log Format) - or to always use a standard TZ like GMC/UTC.

There are probably other ways for the end-user to solve this though, so I'm not sure about making the change

[altendky]

Time zones can be changed. If referring to the offset, then for lots of places the laws change it a couple times a year. Not having this information is a pain when trying to do many things other than just glancing at your own log. For example, when I share logs with a pool and compare with other user's logs I have to remind them to check and share their system's offset.

[altendky]

@wjblanke, you tend to be sensibly concerned about backwards compatibility. Thoughts here? Would this need to be configurable?

[arvidn]

I've we're mostly concerned about this being machine-readable, using posix-time as timestamp would probably be best. No need to worry about time-zones or other head-aches that come with civic time, and it's short. Humans reading the logs will appreciate the screen-space.

The timestamp wouldn't be very human-friendly though.

[paulhainsworth-chia]

Are we ready to merge this so we can close out #8802

[altendky]

Kick CI for a fresh merge/build.

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[trepca]

any idea if this breaks tools that rely on parsing our logs, like chiadog?

[altendky]

I do not know.

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