weird timezone issues in influxdb

[srLinux]

The Problem

hi,
influxdb client always should send the UTC time. It causes weird issues like "in the future" measurements. Take a look over here: https://community.grafana.com/t/weird-timezone-problems/72815

After i changed the timezone on the webpanel to UTC0 the problem went away. It is maybe a influx/grafana related problem but the recommendation is to set the timezone to UTC in on the measurement sending clients.

Version

rolling 15.1.1

Logfile

-

Expected Behavior

No response

Screenshots

No response

Additional Context

No response

[wetneb]

Seems to be a similar problem to #2150.

I would still be interested to hear from @jomjol why this curious arithmetic had to be introduced in the first place:

AI-on-the-edge-device/code/components/jomjol_influxdb/interface_influxdb.cpp

Lines 56 to 63 in dc9f5e5

	struct tm tm;
	strptime(_timestamp.c_str(), PREVALUE_TIME_FORMAT_OUTPUT, &tm);
	time_t t = mktime(&tm); // Time in Localtime (looks like timezone is not used by strptime)
	struct tm * ptm;
	ptm = gmtime ( &t );
	time_t utc = mktime(ptm);
	utc = 2*t - utc; // Take care of timezone (looks difficult, but is easy: t = t + (t - utc), weil t-utc = timezone)

I agree that sending the time in UTC seems much cleaner.

[jomjol]

I agree in general. Does anybody know, how I get the UTC time in the ESP with a local time zone set?

[wetneb]

I think you can just use the same code I had written in the first place: #2278

[srLinux]

Seems to be a similar problem to #2150.

I would still be interested to hear from @jomjol why this curious arithmetic had to be introduced in the first place:

AI-on-the-edge-device/code/components/jomjol_influxdb/interface_influxdb.cpp

Lines 56 to 63 in dc9f5e5

	struct tm tm;
	strptime(_timestamp.c_str(), PREVALUE_TIME_FORMAT_OUTPUT, &tm);
	time_t t = mktime(&tm); // Time in Localtime (looks like timezone is not used by strptime)
	struct tm * ptm;
	ptm = gmtime ( &t );
	time_t utc = mktime(ptm);
	utc = 2*t - utc; // Take care of timezone (looks difficult, but is easy: t = t + (t - utc), weil t-utc = timezone)

I agree that sending the time in UTC seems much cleaner.

sorry, i don't used the search function this time :-)

[jomjol]

I cannot read the time in this functioni due to the following reason:
I want to send the time, when the picture was taken. This is handover as a parameter:
void InfluxDB_V2_Publish(std::string _key, std::string _content, std::string _timestamp)

Unfortunatly the string _timestamp is in local time. Therefore I need to convert it back into UTC. I could not find a function for this.

[jomjol]

I have made a branch to work on this problem: https://github.com/jomjol/AI-on-the-edge-device/tree/debug-influxdb

Please submit updates and changes there.

[jomjol]

Can you test my latest commit here: https://github.com/jomjol/AI-on-the-edge-device/actions/runs/4585284979

Should solve the problem.

[garciaargos]

Can you test my latest commit here: https://github.com/jomjol/AI-on-the-edge-device/actions/runs/4585284979

Should solve the problem.

I just installed it and this works for me so far, Berlin timezone. Thanks!