rattail-tempmon/rattail_tempmon/client.py
2017-07-06 23:38:50 -05:00

153 lines
4.9 KiB
Python

# -*- coding: utf-8 -*-
################################################################################
#
# Rattail -- Retail Software Framework
# Copyright © 2010-2017 Lance Edgar
#
# This file is part of Rattail.
#
# Rattail is free software: you can redistribute it and/or modify it under the
# terms of the GNU General Public License as published by the Free Software
# Foundation, either version 3 of the License, or (at your option) any later
# version.
#
# Rattail is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# Rattail. If not, see <http://www.gnu.org/licenses/>.
#
################################################################################
"""
TempMon client daemon
"""
from __future__ import unicode_literals, absolute_import
import time
import datetime
import random
import socket
import logging
from sqlalchemy.orm.exc import NoResultFound
from rattail.daemon import Daemon
from rattail_tempmon.db import Session, model as tempmon
from rattail.exceptions import ConfigurationError
log = logging.getLogger(__name__)
class TempmonClient(Daemon):
"""
Linux daemon implementation of Tempmon client
"""
def run(self):
"""
This method is invoked upon daemon startup. It is meant to run/loop
"forever" or until daemon stop.
"""
# maybe generate random data instead of reading from true probe
self.dummy_probes = self.config.getbool('tempmon.client', 'dummy_probes', default=False)
# figure out which client we are
hostname = self.config.get('tempmon.client', 'hostname', default=socket.gethostname())
session = Session()
try:
client = session.query(tempmon.Client)\
.filter_by(hostname=hostname)\
.one()
except NoResultFound:
session.close()
raise ConfigurationError("No tempmon client configured for hostname: {}".format(hostname))
client_uuid = client.uuid
self.delay = client.delay or 60
session.close()
# main loop: take readings, pause, repeat
while True:
session = Session()
try:
client = session.query(tempmon.Client).get(client_uuid)
self.delay = client.delay or 60
if client.enabled:
for probe in client.enabled_probes():
self.take_reading(session, probe)
except:
log.exception("Failed to read/record temperature data (but will keep trying)")
session.rollback()
else:
# make sure we show as being online
if not client.online:
client.online = True
try:
session.commit()
except:
# TODO: pretty sure we need to add a retry for this..
log.exception("failed to commit changes to database")
raise
finally:
session.close()
time.sleep(self.delay)
def take_reading(self, session, probe):
"""
Take a single reading and add to Rattail database.
"""
reading = tempmon.Reading()
reading.client = probe.client
reading.probe = probe
reading.degrees_f = self.read_temp(probe)
reading.taken = datetime.datetime.utcnow()
session.add(reading)
return reading
def read_temp(self, probe):
"""
Check for good reading, then format temperature to our liking
"""
if self.dummy_probes:
return self.random_temp(probe)
lines = self.read_temp_raw(probe)
while lines[0].strip()[-3:] != 'YES':
time.sleep(0.2)
lines = self.read_temp_raw(probe)
equals_pos = lines[1].find('t=')
if equals_pos != -1:
temp_string = lines[1][equals_pos+2:]
temp_c = float(temp_string) / 1000.0
temp_f = temp_c * 9.0 / 5.0 + 32.0
return round(temp_f,4)
def read_temp_raw(self, probe):
"""
Function that gets the raw temp data
"""
with open(probe.device_path, 'rt') as therm_file:
return therm_file.readlines()
def random_temp(self, probe):
temp = random.uniform(probe.critical_temp_min - 5, probe.critical_temp_max + 5)
return round(temp, 4)
def make_daemon(config, pidfile=None):
"""
Returns a tempmon client daemon instance.
"""
if not pidfile:
pidfile = config.get('rattail.tempmon', 'client.pid_path',
default='/var/run/rattail/tempmon-client.pid')
return TempmonClient(pidfile, config=config)