Add configurable delay per client; improve try/catch

rattail_tempmon/client.py

@@ -66,37 +66,35 @@ class TempmonClient(Daemon):
             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()
-            client = session.query(tempmon.Client).get(client_uuid)
-            if client.enabled:
 
-                try:
+            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:
+            except:
-                    log.exception("Failed to read/record temperature data")
+                log.exception("Failed to read/record temperature data (but will keep trying)")
-                    session.rollback()
+                session.rollback()
-                    raise
-
-                else:
-                    # make sure we show as being online
-                    if not client.online:
-                        client.online = True
-                    session.commit()
-
-                finally:
-                    session.close()
 
             else:
+                # make sure we show as being online
+                if not client.online:
+                    client.online = True
+                session.commit()
+
+            finally:
                 session.close()
 
-            # TODO: make this configurable
+            time.sleep(self.delay)
-            time.sleep(60)
 
     def take_reading(self, session, probe):
         """

rattail_tempmon/db/alembic/versions/76d52bb064b8_add_client_delay.py

@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+"""add client delay
+
+Revision ID: 76d52bb064b8
+Revises: 7c7d205787b0
+Create Date: 2017-02-07 14:46:11.268920
+
+"""
+
+from __future__ import unicode_literals, absolute_import
+
+# revision identifiers, used by Alembic.
+revision = '76d52bb064b8'
+down_revision = u'7c7d205787b0'
+branch_labels = None
+depends_on = None
+
+from alembic import op
+import sqlalchemy as sa
+import rattail.db.types
+
+
+
+def upgrade():
+
+    # client
+    op.add_column('client', sa.Column('delay', sa.Integer(), nullable=True))
+
+
+def downgrade():
+
+    # client
+    op.drop_column('client', 'delay')

rattail_tempmon/db/model.py

@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  Rattail -- Retail Software Framework
-#  Copyright © 2010-2016 Lance Edgar
+#  Copyright © 2010-2017 Lance Edgar
 #
 #  This file is part of Rattail.
 #
@@ -28,6 +28,7 @@ from __future__ import unicode_literals, absolute_import
 
 import datetime
 
+import six
 import sqlalchemy as sa
 from sqlalchemy import orm
 from sqlalchemy.ext.declarative import declarative_base
@@ -39,6 +40,7 @@ from rattail.db.model.core import ModelBase
 Base = declarative_base(cls=ModelBase)
 
 
+@six.python_2_unicode_compatible
 class Client(Base):
     """
     Represents a tempmon client.
@@ -52,16 +54,23 @@ class Client(Base):
     config_key = sa.Column(sa.String(length=50), nullable=False)
     hostname = sa.Column(sa.String(length=255), nullable=False)
     location = sa.Column(sa.String(length=255), nullable=True)
+
+    delay = sa.Column(sa.Integer(), nullable=True, doc="""
+    Number of seconds to delay between reading / recording temperatures.  If
+    not set, a default of 60 seconds will be assumed.
+    """)
+
     enabled = sa.Column(sa.Boolean(), nullable=False, default=False)
     online = sa.Column(sa.Boolean(), nullable=False, default=False)
 
-    def __unicode__(self):
+    def __str__(self):
         return '{} ({})'.format(self.config_key, self.hostname)
 
     def enabled_probes(self):
         return [probe for probe in self.probes if probe.enabled]
 
 
+@six.python_2_unicode_compatible
 class Probe(Base):
     """
     Represents a probe connected to a tempmon client.
@@ -103,10 +112,11 @@ class Probe(Base):
     status_changed = sa.Column(sa.DateTime(), nullable=True)
     status_alert_sent = sa.Column(sa.DateTime(), nullable=True)
 
-    def __unicode__(self):
+    def __str__(self):
-        return unicode(self.description or '')
+        return self.description
 
 
+@six.python_2_unicode_compatible
 class Reading(Base):
     """
     Represents a single tempurate reading from a tempmon probe.
@@ -136,5 +146,5 @@ class Reading(Base):
     taken = sa.Column(sa.DateTime(), nullable=False, default=datetime.datetime.utcnow)
     degrees_f = sa.Column(sa.Numeric(precision=7, scale=4), nullable=False)
 
-    def __unicode__(self):
+    def __str__(self):
-        return unicode(self.degrees_f)
+        return str(self.degrees_f)

rattail_tempmon/server.py

@@ -60,23 +60,11 @@ class TempmonServerDaemon(Daemon):
     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:
+        clients = session.query(tempmon.Client)\
-            cutoff = self.now - datetime.timedelta(seconds=120)
+                         .filter(tempmon.Client.enabled == True)
-            uuids = [probe.uuid for probe in probes]
+        for client in clients:
-            readings = session.query(tempmon.Reading)\
+            self.check_readings_for_client(session, client)
-                              .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()
@@ -84,27 +72,36 @@ class TempmonServerDaemon(Daemon):
         # TODO: not sure this is really necessary?
         self.set_last_checked()
 
-    def process_readings(self, probes, readings):
+    def check_readings_for_client(self, session, client):
-        for probe in probes:
+        delay = client.delay or 60
-            probe_readings = [r for r in readings if r.probe is probe]
+        cutoff = self.now - datetime.timedelta(seconds=delay + 60)
-            if probe_readings:
+        for probe in client.enabled_probes():
-                reading = sorted(probe_readings, key=lambda r: r.taken)[-1]
+            self.check_readings_for_probe(session, probe, cutoff)
 
-                if (reading.degrees_f <= probe.critical_temp_min or
+    def check_readings_for_probe(self, session, probe, cutoff):
-                      reading.degrees_f >= probe.critical_temp_max):
+        readings = session.query(tempmon.Reading)\
-                    self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_CRITICAL_TEMP, reading)
+                          .filter(tempmon.Reading.probe == probe)\
+                          .filter(tempmon.Reading.taken >= cutoff)\
+                          .all()
+        if readings:
+            # we really only care about the latest reading
+            reading = sorted(readings, key=lambda r: r.taken)[-1]
 
-                elif reading.degrees_f < probe.good_temp_min:
+            if (reading.degrees_f <= probe.critical_temp_min or
-                    self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_LOW_TEMP, reading)
+                  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_max:
+            elif reading.degrees_f < probe.good_temp_min:
-                    self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_HIGH_TEMP, reading)
+                self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_LOW_TEMP, reading)
 
-                else: # temp is good
+            elif reading.degrees_f > probe.good_temp_max:
-                    self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_GOOD_TEMP, reading)
+                self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_HIGH_TEMP, reading)
 
-            else: # no readings for probe
+            else: # temp is good
-                self.update_status(probe, self.enum.TEMPMON_PROBE_STATUS_ERROR)
+                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):
         data = {

setup.py

@@ -65,6 +65,7 @@ requires = [
     # package                           # low                   high
 
     'rattail[db]',                      # 0.7.46
+    'six',                              # 1.10.0
 ]