Datetime format: Use suffix "Z" to indicate UTC when it applies, or use %z, but not both.

[aaron-sweeney]

I recommend rolling back the commit bc7e26f (logmatic/init.py) as per my comment to @lokoms.

The suffix "Z" indicates UTC and should not be used in combination with %z (+/-HHMM).

In cases where the system time zone is set to something other than UTC, for example US Mountain Standard Time, this change to line 21 (i.e. "Z%z") will result in nonsensical timestamps, such as "2016-12-18T16:42:03Z-0700." ("Z" indicates UTC, but -0700 indicates UTC-0700, so which is it?) As line 21 is calling the method utcnow(), you are assured that the timestamp is expressed in UTC, so the "Z" suffix will always apply. The "%z" should be removed from line 21.

Similarly, on line 11, introducing the suffix "Z" in combination with %z leads to confusion when the system time zone is not set to UTC. In this case, one is not guaranteed that the timestamp will be expressed as UTC, and so the suffix "Z" should not be included.

Cordially,
Aaron

[gpolaert]

@lokoms Could you check this issue?

[aaron-sweeney]

I would direct the interested reader to ISO 8601 and IETF RFC 3339. As it stands now, logmatic/init.py is not compliant with either of these standards for date/time. "Z" is a substitute for "+00:00" or "+0000" and should not be used in combination with numerical time-zone offsets.

Cordially,
Aaron