Initial commit

rattail_tempmon/server.py

@@ -0,0 +1,161 @@
+# -*- 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 server daemon
+"""
+
+from __future__ import unicode_literals, absolute_import
+
+import time
+import datetime
+import logging
+
+from rattail.db import Session, api
+from rattail_tempmon import Session as TempmonSession
+from rattail.daemon import Daemon
+from rattail.time import localtime, make_utc
+from rattail.mail import send_email
+
+
+log = logging.getLogger(__name__)
+
+
+class TempmonServerDaemon(Daemon):
+    """
+    Linux daemon implementation of tempmon server.
+    """
+    timefmt = '%Y-%m-%d %H:%M:%S'
+
+    def run(self):
+        """
+        Keeps an eye on tempmon readings and sends alerts as needed.
+        """
+        self.extra_emails = self.config.getlist('rattail.tempmon', 'extra_emails', default=[])
+        while True:
+            self.check_readings()
+            time.sleep(5)
+
+    def check_readings(self):
+        self.now = make_utc()
+        session = TempmonSession()
+        probes = session.query(tempmon.Probe)\
+                        .join(tempmon.Client)\
+                        .filter(tempmon.Client.enabled == True)\
+                        .filter(tempmon.Probe.enabled == True)\
+                        .all()
+
+        if probes:
+            cutoff = self.now - datetime.timedelta(seconds=120)
+            uuids = [probe.uuid for probe in probes]
+            readings = session.query(tempmon.Reading)\
+                              .filter(tempmon.Reading.probe_uuid.in_(uuids))\
+                              .filter(tempmon.Reading.taken >= cutoff)\
+                              .all()
+            self.process_readings(probes, readings)
+
+        else:
+            log.warning("found no enabled probes!")
+
+        session.commit()
+        session.close()
+
+        # TODO: not sure this is really necessary?
+        self.set_last_checked()
+
+    def process_readings(self, probes, readings):
+        for probe in probes:
+            probe_readings = [r for r in readings if r.probe is probe]
+            if probe_readings:
+                reading = sorted(probe_readings, key=lambda r: r.taken)[-1]
+
+                if (reading.degrees_f <= probe.critical_temp_min or
+                      reading.degrees_f >= probe.critical_temp_max):
+                    self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_CRITICAL_TEMP, reading)
+
+                elif reading.degrees_f < probe.good_temp_min:
+                    self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_LOW_TEMP, reading)
+
+                elif reading.degrees_f > probe.good_temp_max:
+                    self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_HIGH_TEMP, reading)
+
+                else: # temp is good
+                    self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_GOOD_TEMP, reading)
+                
+            else: # no readings for probe
+                self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_ERROR)
+
+    def update_status(self, probe, status, reading=None):
+        prev_status = probe.status
+        if probe.status != status:
+            probe.status = status
+            probe.status_changed = self.now
+            probe.status_alert_sent = None
+
+        # no email if status is good
+        if status == self.enum.TEMPMON_PROBE_STATUS_GOOD_TEMP:
+            return
+
+        # no email if we already sent one...until timeout is reached
+        if probe.status_alert_sent:
+            timeout = datetime.timedelta(minutes=probe.status_alert_timeout)
+            if (self.now - probe.status_alert_sent) <= timeout:
+                return
+
+        msgtypes = {
+            self.enum.TEMPMON_PROBE_STATUS_LOW_TEMP             : 'tempmon_low_temp',
+            self.enum.TEMPMON_PROBE_STATUS_HIGH_TEMP            : 'tempmon_high_temp',
+            self.enum.TEMPMON_PROBE_STATUS_CRITICAL_TEMP        : 'tempmon_critical_temp',
+            self.enum.TEMPMON_PROBE_STATUS_ERROR                : 'tempmon_error',
+        }
+
+        data = {
+            'probe': probe,
+            'status': self.enum.TEMPMON_PROBE_STATUS[status],
+            'reading': reading,
+            'taken': localtime(self.config, make_utc(reading.taken, tzinfo=True)) if reading else None,
+            'now': localtime(self.config),
+        }
+
+        send_email(self.config, msgtypes[status], data)
+
+        # maybe send more emails if config said so
+        for msgtype in self.extra_emails:
+            send_email(self.config, msgtype, data)
+
+        probe.status_alert_sent = self.now
+
+    def set_last_checked(self):
+        session = Session()
+        api.save_setting(session, 'tempmon.server.last_checked', self.now.strftime(self.timefmt))
+        session.commit()
+        session.close()
+
+
+def make_daemon(config, pidfile=None):
+    """
+    Returns a tempmon server daemon instance.
+    """
+    if not pidfile:
+        pidfile = config.get('rattail.tempmon', 'server.pid_path',
+                             default='/var/run/rattail/tempmon-server.pid')
+    return TempmonServerDaemon(pidfile, config=config)