smircd.py

#!/usr/bin/env python
#
# Monitor a directory for incoming SMS messages and deal with them as they arrive.
#
# Note that because this daemon includes django models and thus has a dependency
# on the django framework, it requires the DJANGO_SETTINGS_MODULE environment
# variable to be set.
#
# In general, an example DJANGO_SETTINGS_MODULE environment variable setting
# will look like this:
#
#	export DJANGO_SETTINGS_MODULE="smirc.settings"
#
# See http://docs.djangoproject.com/en/dev/topics/settings/ for more information.
#
import datetime
import inspect
import logging
import os
import pyinotify
import signal
import sys
import traceback
from django.conf import settings
from django.core.mail import mail_admins
from smirc.chat.models import Membership
from smirc.command.models import SmircCommandException
from smirc.message.models import SmircMessageException
from smirc.message.models import SmircOutOfAreaException
from smirc.message.models import SmircRawMessageException
from smirc.message.models import SMSToolsMessage

__version__ = '$Rev$'
logger = logging.getLogger('smircd.py')

class SMSFileHandler(pyinotify.ProcessEvent):
	def process_IN_MODIFY(self, event):
		logger.debug('event IN_MODIFY occurred for %s' % event.pathname)
		if (os.path.splitext(os.path.basename(event.pathname))[0] == 'smsd_script'):
			logger.warning('skipping SMSTools script %s' % event.pathname)
			return
		if (os.path.basename(event.pathname).find('-concatenated') != -1):
			logger.warning('skipping concatenated SMSTools transitional message %s' % event.pathname)
			return
		message = SMSToolsMessage()
		response = None
		try:
			message.receive(event.pathname)
		except (SmircCommandException, SmircMessageException) as e:
			response = SMSToolsMessage()
			response.body = str(e)
			response.system = True
		except SmircOutOfAreaException as e:
			logger.warning('message out of area exception: %s' % (str(e)))
		except SmircRawMessageException as e:
			logger.error('raw message exception occurred while receiving messages %s: %s' % (event.pathname, e))
		except Exception as e:
			logger.exception('unhandled exception occurred while receiving message %s: %s' % (event.pathname, e))

			subject = 'unhandled exception occurred while receiving message %s' % (event.pathname)
			message = '\n'.join(traceback.format_exception(*(sys.exc_info())))
			mail_admins(subject, message, fail_silently=True)
		else:
			if (message.command):
				response = SMSToolsMessage()
				try:
					response.body = message.command.execute()
				except SmircCommandException as e:
					response.body = str(e)
				response.system = True
			else:
				message.sender.last_active = datetime.datetime.utcnow()
				message.sender.save()
				try:
					for recipient in Membership.objects.filter(conversation=message.sender.conversation).exclude(user=message.sender.user):
						message.send(recipient.user.get_profile().phone_number)
				except Membership.DoesNotExist:
					pass
				except Exception as e:
					logger.exception('unhandled exception occurred while forwarding message: %s' % (e))
		try:
			os.rename(event.pathname, '%s/archived/%s' % (settings.SMSTOOLS['inbound_dir'], os.path.basename(event.pathname)))
		except OSError as e:
			logger.exception('operating system exception occurred while archiving message %s: %s' % (event.pathname, e))
		if response is not None:
			try:
				response.send(message.raw_phone_number)
			except Exception as e:
				logger.exception('unhandled exception occurred while sending message to %s: %s' % (message.raw_phone_number, e))

def signal_handler(signum, _unused_frame):
	global smircd_terminate
	
	sigdesc = 'UNKNOWN'
	for member in inspect.getmembers(signal):
		if member[0][0:3] == 'SIG' and member[1] == signum:
			sigdesc = member[0]
			break
	if signum in [ signal.SIGINT, signal.SIGTERM, signal.SIGQUIT ]:
		logger.info('signal_handler received signal %s(%d), setting termination flag' % (sigdesc, signum))
		smircd_terminate = True
	elif signum in [ signal.SIGHUP ]:
		logger.warning('signal_handler ignoring signal %s(%d)' % (sigdesc, signum))
	else:
		logger.error('signal_handler ignoring unhandled signal %s(%d)' % (sigdesc, signum))

def smircd_sanity_check():
	errors = 0

	if not os.path.exists(settings.SMSTOOLS['inbound_dir']):
		logger.error('inbound directory %s does not exist' % (settings.SMSTOOLS['inbound_dir']))
		errors += 1
	else:
		if not os.path.isdir(settings.SMSTOOLS['inbound_dir']):
			logger.error('inbound directory %s is not a directory' % (settings.SMSTOOLS['inbound_dir']))
			errors += 1
		else:
			if not os.access(settings.SMSTOOLS['inbound_dir'], os.R_OK):
				logger.error('inbound directory %s is not readable' % (settings.SMSTOOLS['inbound_dir']))
				errors += 1

	if not os.path.exists(settings.SMSTOOLS['outbound_dir']):
		logger.error('outbound directory %s does not exist' % (settings.SMSTOOLS['outbound_dir']))
		errors += 1
	else:
		if not os.path.isdir(settings.SMSTOOLS['outbound_dir']):
			logger.error('outbound directory %s is not a directory' % (settings.SMSTOOLS['outbound_dir']))
			errors += 1
		else:
			if not os.access(settings.SMSTOOLS['outbound_dir'], os.W_OK):
				logger.error('outbound directory %s is not writable' % (settings.SMSTOOLS['outbound_dir']))
				errors += 1

	if errors > 0:
		sys.exit(-2)
	
smircd_terminate = False

if __name__ == '__main__':
	logger.debug('settings.SMSTOOLS: %s', str(settings.SMSTOOLS))
	smircd_sanity_check()

	if not os.path.exists('%s/archived' % (settings.SMSTOOLS['inbound_dir'])):
		os.mkdir('%s/archived' % (settings.SMSTOOLS['inbound_dir']))

	signal.signal(signal.SIGHUP, signal_handler)
	signal.signal(signal.SIGINT, signal_handler)
	signal.signal(signal.SIGTERM, signal_handler)
	signal.signal(signal.SIGQUIT, signal_handler)

	watch_manager = pyinotify.WatchManager()
	sms_file_handler = SMSFileHandler()
	notifier = pyinotify.Notifier(watch_manager, sms_file_handler)
	watch_manager.add_watch(settings.SMSTOOLS['inbound_dir'], pyinotify.EventsCodes.FLAG_COLLECTIONS['OP_FLAGS']['IN_MODIFY'])
	
	# TODO: deal with pre-existing files (i.e. files that have already been received and
	# are sitting on our inbound directory right now.
	while True:
		notifier.process_events()
		if smircd_terminate == True:
			notifier.stop()
			break
		if notifier.check_events(timeout=500):
			notifier.read_events()