Catch another time error during DST change

Signed-off-by: Jim Easterbrook <jim@jim-easterbrook.me.uk>

src/pywws/Plot.py

@@ -533,7 +533,7 @@
 from pywws import DataStore
 from pywws import Localisation
 from pywws.Logger import ApplicationLogger
-from pywws.TimeZone import Local, utc
+from pywws.TimeZone import Local, local_utc_offset, utc
 
 class GraphNode(object):
     def __init__(self, node):
@@ -596,19 +596,12 @@ def __init__(self, params, status, raw_data, hourly_data,
             raise RuntimeError(
                 'Directory "' + self.work_dir + '" does not exist.')
 
-    def _local_offset(self, time):
-        try:
-            result = Local.utcoffset(time)
-        except pytz.InvalidTimeError:
-            result = Local.utcoffset(time + HOUR)
-        return result
-
     def _eval_time(self, time_str):
         # get timestamp of last data item
         result = self.hourly_data.before(datetime.max)
         if not result:
             result = datetime.utcnow()    # only if no hourly data
-        result += self._local_offset(result)
+        result += local_utc_offset(result)
         # set to start of the day
         result = result.replace(hour=0, minute=0, second=0, microsecond=0)
         # apply time string
@@ -650,7 +643,7 @@ def DoPlot(self, input_file, output_file):
             self.x_hi = self.hourly_data.before(datetime.max)
             if not self.x_hi:
                 self.x_hi = datetime.utcnow()    # only if no hourly data
-            self.x_hi += self._local_offset(self.x_hi)
+            self.x_hi += local_utc_offset(self.x_hi)
             if self.duration < timedelta(hours=6):
                 # set end of graph to start of the next minute after last item
                 self.x_hi += timedelta(seconds=55)
@@ -660,7 +653,7 @@ def DoPlot(self, input_file, output_file):
                 self.x_hi += timedelta(minutes=55)
                 self.x_hi = self.x_hi.replace(minute=0, second=0)
             self.x_lo = self.x_hi - self.duration
-        self.utcoffset = self._local_offset(self.x_hi)
+        self.utcoffset = local_utc_offset(self.x_hi)
         # open gnuplot command file
         self.tmp_files = []
         cmd_file = os.path.join(self.work_dir, 'plot.cmd')

src/pywws/Tasks.py

@@ -32,7 +32,7 @@
 from pywws.calib import Calib
 from pywws import Plot
 from pywws import Template
-from pywws.TimeZone import STDOFFSET, Local
+from pywws.TimeZone import STDOFFSET, local_utc_offset
 from pywws.toservice import ToService
 from pywws import Upload
 from pywws import WindRose
@@ -99,7 +99,7 @@ def __init__(self, params, status,
             self.cron[section].get_prev()
             last_update = self.status.get_datetime('last update', section)
             if last_update:
-                last_update = last_update + Local.utcoffset(last_update)
+                last_update = last_update + local_utc_offset(last_update)
                 while self.cron[section].get_current(datetime) <= last_update:
                     self.cron[section].get_next()
         # create service uploader objects
@@ -279,7 +279,7 @@ def _do_cron(self, live_data=None):
         if not now:
             now = datetime.utcnow()
         # convert to local time
-        local_now = now + Local.utcoffset(now)
+        local_now = now + local_utc_offset(now)
         # get list of due sections
         sections = []
         for section in self.cron:

src/pywws/TimeZone.py

@@ -41,13 +41,24 @@
 import pytz
 import tzlocal
 
+from pywws.constants import HOUR
+
 utc = pytz.utc
 Local = tzlocal.get_localzone()
 
 _now = datetime.now(tz=Local)
 STDOFFSET = _now.utcoffset() - _now.dst()
 del _now
 
+def local_utc_offset(time):
+    try:
+        result = Local.utcoffset(time)
+    except pytz.InvalidTimeError:
+        result = Local.utcoffset(time + HOUR)
+    except pytz.AmbiguousTimeError:
+        result = Local.utcoffset(time - HOUR)
+    return result
+
 def main():
     print datetime.now().strftime('%Y/%m/%d %H:%M %Z')
     print datetime.now(utc).strftime('%Y/%m/%d %H:%M %Z')

src/pywws/__init__.py

@@ -1,3 +1,3 @@
 __version__ = '16.10.0'
-_release = '1363'
-_commit = 'aa707bc'
+_release = '1364'
+_commit = '7b86a51'