renderer.py

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