Initial commit

rattail_tempmon/client.py

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+# -*- coding: utf-8 -*-
+################################################################################
+#
+#  Rattail -- Retail Software Framework
+#  Copyright © 2010-2016 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 Affero 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 Affero General Public License for
+#  more details.
+#
+#  You should have received a copy of the GNU Affero 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 socket
+import logging
+
+from rattail.daemon import Daemon
+from rattail_tempmon.db import Session, model as tempmon
+
+
+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.
+        """
+        # figure out which client we are
+        session = Session()
+        client = session.query(tempmon.Client)\
+                        .filter_by(hostname=socket.gethostname())\
+                        .one()
+        client_uuid = client.uuid
+        session.close()
+
+        # main loop: take readings, pause, repeat
+        while True:
+            session = Session()
+            client = session.query(tempmon.Client).get(client_uuid)
+            if client.enabled:
+
+                try:
+                    for probe in client.enabled_probes():
+                        self.take_reading(session, probe)
+
+                except:
+                    log.exception("Failed to read/record temperature data")
+                    session.rollback()
+                    raise
+
+                else:
+                    # make sure we show as being online
+                    if not client.online:
+                        client.online = True
+                    session.commit()
+
+                finally:
+                    session.close()
+
+            else:
+                session.close()
+
+            # TODO: make this configurable
+            time.sleep(60)
+
+    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
+        """
+        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 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)