[DRAFT] DAQ: Assume naive human-readable timestamps w/o timezone information to be in UTC

CHANGES.rst

@@ -9,6 +9,11 @@ in progress
 - CI: Update to Grafana 9.3.0
 - DAQ: Mask ``PASSKEY`` variable coming from HTTP, emitted by Ecowitt
 
+Breaking changes
+----------------
+
+- DAQ: Obtain naive timestamps as UTC by default, instead of CET
+
 
 .. _kotori-0.27.0:
 

kotori/io/protocol/util.py

@@ -4,7 +4,7 @@
 import arrow
 import datetime
 from six import text_type
-from dateutil.tz import gettz
+from dateutil.tz import gettz, tzutc
 from dateutil.parser import parse
 from pyramid.settings import asbool
 from twisted.web import http
@@ -177,23 +177,27 @@ def slugify_datettime(dstring):
     return arrow.get(dstring).to('utc').format('YYYYMMDDTHHmmss')
 
 
-def parse_timestamp(timestamp):
+def parse_timestamp(timestamp, use_utc=False):
 
     if isinstance(timestamp, text_type):
 
         # FIXME: Maybe use system timezone here by default.
         # TODO: Make configurable via channel settings.
 
-        # HACK: Assume CET (Europe/Berlin) for human readable timestamp w/o timezone offset
+        # Handle naive human-readable timestamps w/o timezone offset.
         qualified = any([token in timestamp for token in ['Z', '+', ' CET', ' CEST']])
         if not qualified:
-            timestamp += ' CET'
+            # Assume CET (Europe/Berlin) (default), or UTC.
+            if use_utc:
+                timestamp += ' UTC'
+            else:
+                timestamp += ' CET'
 
         # Parse datetime string
         # Remark: Maybe use pandas.tseries.tools.parse_time_string?
         # TODO: Cache results of call to gettz to improve performance
         berlin = gettz('Europe/Berlin')
-        tzinfos = {'CET': berlin, 'CEST': berlin}
+        tzinfos = {'UTC': tzutc(), 'CET': berlin, 'CEST': berlin}
         timestamp = parse(timestamp, tzinfos=tzinfos)
 
     return timestamp

test/test_ecowitt.py

@@ -1,4 +1,6 @@
 import json
+
+from kotori.io.protocol.util import parse_timestamp
 from test.settings.mqttkit import PROCESS_DELAY_HTTP, influx_sensors, settings
 from test.util import http_form_sensor, sleep
 
@@ -85,4 +87,8 @@ def test_ecowitt_post(machinery, create_influxdb, reset_influxdb):
     # Make sure this will not be public.
     assert "PASSKEY" not in record
 
+    # Make sure decoding the timestamp works.
+    print(record["time"])
+    assert parse_timestamp(record["time"]) == parse_timestamp("2023-02-20 16:02:19", use_utc=True)
+
     yield record