config.py

# -*- coding: utf-8 -*-

"""
File for dealing with the configuration of wxPi.py.
"""

import os
import logging
import threading
from ConfigParser import SafeConfigParser, NoSectionError

from led import GPIOLED as LED

__version__ = '0.2'
__all__ = ['CONFIG_FILE', 'loadConfig', 'initLEDs', 'saveConfig', '__version__', '__all__']


# Logger instance
confLogger = logging.getLogger('__main__')


# Files
## Base path for the various files needed/generated by wxPi.py
_BASE_PATH = os.path.dirname(os.path.abspath(__file__))

## Wunderground Configuration
CONFIG_FILE = os.path.join(_BASE_PATH, 'wxPi.config')


class LockingConfigParser(SafeConfigParser):
	"""
	Sub-class of ConfigParser.SafeConfigParser that wraps the get, set, and 
	write methods with a semaphore to ensure that only one get/set/read/write 
	happens at a time.  The sub-class also adds asDict and fromDict methods
	to make it easier to tie the configuration into webforms.
	"""
	
	_lock = threading.Semaphore()
	
	def get(self, *args, **kwds):
		"""
		Locked get() method.
		"""
		
		#self._lock.acquire()
		value = SafeConfigParser.get(self, *args, **kwds)
		#self._lock.release()
		return value
		
	def getint(self, *args, **kwds):
		"""
		Locked getint() method.
		"""
		
		value = SafeConfigParser.getint(self, *args, **kwds)
		return int(value)
		
	def getfloat(self, *args, **kwds):
		"""
		Locked getfloat() method.
		"""
		
		value = SafeConfigParser.getfloat(self, *args, **kwds)
		return float(value)
		
	def getbool(self, *args, **kwds):
		"""
		Locked getbool() method.
		"""
		
		value = SafeConfigParser.get(self, *args, **kwds)
		if value.lower() in ('true', 'enabled', 'on', 'yes'):
			value = True
		else:
			value = False
		return value
		
	def set(self, *args, **kwds):
		"""
		Locked set() method.
		"""
		
		#self._lock.acquire()
		SafeConfigParser.set(self, *args, **kwds)
		#self._lock.release()
		
	def read(self, *args, **kwds):
		"""
		Locked read() method.
		"""
		
		SafeConfigParser.read(self, *args, **kwds)
		
	def write(self, *args, **kwds):
		"""
		Locked write() method.
		"""
		
		SafeConfigParser.write(self, *args, **kwds)
		
	def asDict(self):
		"""
		Return the configuration as a dictionary with keys structured as
		section-option.
		"""
		
		configDict = {}
		for section in self.sections():
			for keyword,value in self.items(section):
				configDict['%s-%s' % (section.lower(), keyword)] = value
		
		# Done
		return configDict
		
	def fromDict(self, configDict):
		"""
		Given a dictionary created by asDict(), update the configuration 
		as needed.
		"""
		
		# Loop over the pairs in the dictionary
		for key,value in configDict.iteritems():
			try:
				section, keyword = key.split('-', 1)
				section = section.capitalize()
				self.set(section, keyword, value)
			except Exception, e:
				print str(e)
				pass
				
		# Done
		return True


def loadConfig(filename):
	"""
	Read in the configuration file and return a dictionary of the 
	parameters.
	"""
	
	# Initial configuration file
	config = LockingConfigParser()
	
	## Dummy WUnderground PWS information
	##  1) ID - PWS ID
	##  2) Password - PWS upload password
	config.add_section('Account')
	config.set('Account', 'id', 'Your_Id_Here')
	config.set('Account', 'password', 'Your_Password_Here')
	
	## Dummy station information
	##  1) elevation - Station elevation in meters
	##  2) duration - Duration, in seconds, to record data for
	##  3) radioPin - GPIO pin that the radio is connected to
	##  4) enableBMP085 - enable reading a BMP085/BMP180 sensor over I2C
	##  5) includeIndoor - Whether or not to include indoor data
	config.add_section('Station')
	config.set('Station', 'elevation', '0.0')
	config.set('Station', 'duration', '60.0')
	config.set('Station', 'radiopin', '18')
	config.set('Station', 'enablebmp085', 'True')
	config.set('Station', 'includeindoor', 'False')
	
	## Dummy LED information
	##  1) redPin - GPIO pin that a red LED is attached to
	##  2) yellowPin - GPIO pin that a yellow LED is attached to
	##  3) greenPin - GPIO pin that a green LED is attached to
	config.add_section('LED')
	config.set('LED', 'redpin', '27')
	config.set('LED', 'yellowpin', '17')
	config.set('LED', 'greenpin', '4')
	
	# Try to read in the actual configuration file
	try:
		config.read(filename)
		confLogger.info('Loaded configuration from \'%s\'', os.path.basename(filename))
		
	except:
		pass
		
	# Done
	return config



def initLEDs(config):
	"""
	Given a LockingConfigParser configuration instance, create a dictionary of 
	GPIOLED instances to control the various LEDs.
	"""
	
	# Create the GPIOLED instances
	leds = {}
	for color in ('red', 'yellow', 'green'):
		try:
			pin = config.get('LED', '%spin' % color)
			leds[color] = LED(pin)
			
		except NoSectionError:
			leds[color] = LED(-1)
			
	# Done
	return leds


def saveConfig(filename, config):
	"""
	Given a filename and a LockingConfigParser, write the configuration to 
	disk.
	"""
	
	fh = open(filename, 'w')
	config.write(fh)
	fh.close()
	
	confLogger.info('Saved configuration to \'%s\'', os.path.basename(filename))