renderer.py

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