default tasks fail to run

[ncouture]

This was encountered while following the installation instructions (http://rsaikali.github.io/django-skwissh/#installation) against the master branch.

To reproduce, after the ``manage.py installtasks'' installation step type:

crontab -l | cut -d ' '  -f6-100 | while read line; do $line; done

In order to execute the tasks installed in crontab.

Result:

(skwissh)skwissh@portemanteau ~/monitoring $ /home/skwissh/.virtualenvs/skwissh/bin/python /home/skwissh/monitoring/manage.py runtask getMeasures --settings=monitoring.settings 
(skwissh)skwissh@portemanteau ~/monitoring $ /home/skwissh/.virtualenvs/skwissh/bin/python /home/skwissh/monitoring/manage.py runtask averageDay --settings=monitoring.settings 
Exception in thread SkwisshAverage.MeasureDay.CPU_(Wait_IO):
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 763, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/skwissh/.virtualenvs/skwissh/local/lib/python2.7/site-packages/django_skwissh-0.0.8-py2.7.egg/skwissh/cron.py", line 147, in calculateAveragesForPeriod
    values = [float(measure.value.split(";")[i]) for measure in measures]
ValueError: invalid literal for float(): 0.0 wa

(skwissh)skwissh@portemanteau ~/monitoring $ /home/skwissh/.virtualenvs/skwissh/bin/python /home/skwissh/monitoring/manage.py runtask averageWeek --settings=monitoring.settings 
Exception in thread SkwisshAverage.MeasureWeek.CPU_(Wait_IO):
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 763, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/skwissh/.virtualenvs/skwissh/local/lib/python2.7/site-packages/django_skwissh-0.0.8-py2.7.egg/skwissh/cron.py", line 147, in calculateAveragesForPeriod
    values = [float(measure.value.split(";")[i]) for measure in measures]
ValueError: invalid literal for float(): 0.0 wa

(skwissh)skwissh@portemanteau ~/monitoring $ /home/skwissh/.virtualenvs/skwissh/bin/python /home/skwissh/monitoring/manage.py runtask averageMonth --settings=monitoring.settings 
Exception in thread SkwisshAverage.MeasureMonth.CPU_(Wait_IO):
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 763, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/skwissh/.virtualenvs/skwissh/local/lib/python2.7/site-packages/django_skwissh-0.0.8-py2.7.egg/skwissh/cron.py", line 147, in calculateAveragesForPeriod
    values = [float(measure.value.split(";")[i]) for measure in measures]
ValueError: invalid literal for float(): 0.0 wa

At first glance it seems like the following two lines from cron.py are the culprits:

values = [float(measure.value.split(";")[i]) for measure in measures]
all_values.append(str(round(float(sum(values) / len(values)), 2)))