renderer.py

   1 import time
   2 from datetime import datetime
   3 from decorators import invokation_logged
   4
   5 class renderer(object):
   6     """Base class for something that can render."""
   7
   8     @invokation_logged
   9     def render(self):
  10         pass
  11
  12     def get_name(self):
  13         return self.__class__.__name__
  14
  15 class abstaining_renderer(renderer):
  16     """A renderer that doesn't do it all the time."""
  17     def __init__(self, name_to_timeout_dict):
  18         self.name_to_timeout_dict = name_to_timeout_dict;
  19         self.last_runs = {}
  20         for key in name_to_timeout_dict:
  21             self.last_runs[key] = 0
  22
  23     def should_render(self, keys_to_skip):
  24         now = time.time()
  25         for key in self.name_to_timeout_dict:
  26             if (((now - self.last_runs[key]) > self.name_to_timeout_dict[key]) and
  27                 key not in keys_to_skip):
  28                 return key
  29         return None
  30
  31     def render(self):
  32         tries_per_key = {}
  33         keys_to_skip = set()
  34         while True:
  35             key = self.should_render(keys_to_skip)
  36             if key == None:
  37                 break
  38
  39             if key in tries_per_key:
  40                 tries_per_key[key] += 1
  41             else:
  42                 tries_per_key[key] = 0
  43
  44             if tries_per_key[key] >= 3:
  45                 print('renderer: Too many failures for "%s.%s", giving up' % (
  46                     self.get_name(), key))
  47                 keys_to_skip.add(key)
  48             else:
  49                 msg = 'renderer: executing "%s.%s"' % (self.get_name(), key)
  50                 if (tries_per_key[key] > 1):
  51                     msg = msg + " (retry #%d)" % tries_per_key[key]
  52                 print(msg)
  53                 if (self.periodic_render(key)):
  54                     self.last_runs[key] = time.time()
  55
  56     @invokation_logged
  57     def periodic_render(self, key):
  58         pass
  59
  60 class debuggable_abstaining_renderer(abstaining_renderer):
  61     def __init__(self, name_to_timeout_dict, debug):
  62         super(debuggable_abstaining_renderer, self).__init__(name_to_timeout_dict);
  63         self.debug = debug
  64
  65     def debug_prefix(self):
  66         return self.get_name()
  67
  68     def being_debugged(self):
  69         return self.debug
  70
  71     def debug_print(self, template, *args):
  72         try:
  73             if self.being_debugged():
  74                 if args:
  75                     msg = template.format(args)
  76                 else:
  77                     msg = template
  78
  79                 # current date and time
  80                 now = datetime.now()
  81                 timestamp = now.strftime("%d-%b-%Y (%H:%M:%S.%f)")
  82                 print("%s(%s): %s" % (self.debug_prefix(), timestamp, msg))
  83         except Exception as e:
  84             print("Exception in debug_print!")
  85             print(e)