smart_home/thermometers.py

   1 #!/usr/bin/env python3
   2
   3 # © Copyright 2021-2022, Scott Gasch
   4
   5 """Code involving querying various smart home thermometers."""
   6
   7 import logging
   8 import urllib.request
   9 from typing import Optional
  10
  11 logger = logging.getLogger()
  12
  13
  14 class ThermometerRegistry(object):
  15     """A registry of thermometer hosts / names and how to talk with them."""
  16
  17     def __init__(self):
  18         self.thermometers = {
  19             'house_outside': ('10.0.0.75', 'outside_temp'),
  20             'house_inside_downstairs': ('10.0.0.75', 'inside_downstairs_temp'),
  21             'house_inside_upstairs': ('10.0.0.75', 'inside_upstairs_temp'),
  22             'house_computer_closet': ('10.0.0.75', 'computer_closet_temp'),
  23             'house_crawlspace': ('10.0.0.75', 'crawlspace_temp'),
  24             'cabin_outside': ('192.168.0.107', 'outside_temp'),
  25             'cabin_inside': ('192.168.0.107', 'inside_temp'),
  26             'cabin_crawlspace': ('192.168.0.107', 'crawlspace_temp'),
  27             'cabin_hottub': ('192.168.0.107', 'hottub_temp'),
  28         }
  29
  30     def read_temperature(self, location: str, *, convert_to_fahrenheit=False) -> Optional[float]:
  31         """Read the current value of a thermometer (in celsius unless
  32         convert_to_fahrenheit is True) and return it.  Return None on
  33         error.
  34
  35         >>> registry = ThermometerRegistry()
  36         >>> registry.read_temperature('unknown') is None
  37         True
  38
  39         >>> temp = registry.read_temperature('house_computer_closet')
  40         >>> temp is None
  41         False
  42         >>> temp > 0.0
  43         True
  44
  45         """
  46
  47         record = self.thermometers.get(location, None)
  48         if record is None:
  49             logger.error(
  50                 'Location %s is not known.  Valid locations are %s.',
  51                 location,
  52                 self.thermometers.keys(),
  53             )
  54             return None
  55
  56         url = f'http://{record[0]}/~pi/{record[1]}'
  57         logger.debug('Constructed URL: %s', url)
  58         try:
  59             www = urllib.request.urlopen(url, timeout=3)
  60             temp = www.read().decode('utf-8')
  61             temp = float(temp)
  62             if convert_to_fahrenheit:
  63                 temp *= 9 / 5
  64                 temp += 32.0
  65                 temp = round(temp)
  66         except Exception as e:
  67             logger.exception(e)
  68             logger.error('Failed to read temperature at URL: %s', url)
  69             temp = None
  70         finally:
  71             if www is not None:
  72                 www.close()
  73         return temp
  74
  75
  76 if __name__ == '__main__':
  77     import doctest
  78
  79     doctest.testmod()