def __init__(self, period, threshold, eval_func,
**kwargs):
self.period = int(period)
self.threshold = float(threshold)
self.eval_func = eval_func
self.queue = dict()
self.fired = False
assert self.id, "Decision id not defined"
self.channel = ChannelWrapper(self.id,
self.exchange_type,
self.on_update,
publish=False,
manual_ack=False,
**kwargs)
self._kwargs = kwargs
self._create()
class DecisionBase(object):
"""
Base class for Decision object. Defines common methods
and properties, needed for a Decision class to operate
with data, coming from the sources
Arguments:
.. period:: Integer, the period to collect statistics
in seconds
.. threshold:: Threshold value to fire an event.
Depends on the aggregate_type
.. eval_func:: Function for evaluation logic.
Should accept iterable values and return
threshold-comparable value
"""
exchange_type = 'topic'
def __init__(self, period, threshold, eval_func,
**kwargs):
self.period = int(period)
self.threshold = float(threshold)
self.eval_func = eval_func
self.queue = dict()
self.fired = False
assert self.id, "Decision id not defined"
self.channel = ChannelWrapper(self.id,
self.exchange_type,
self.on_update,
publish=False,
manual_ack=False,
**kwargs)
self._kwargs = kwargs
self._create()
def _create(self):
"""
Called in the constructor, useful to be re-declared
in a child classes to apply additional actions upon
instance creation
"""
pass
def connect(self, **kwargs):
"""
Connect to queue and start consuming
"""
# Set the signal handler to gracefully disconnect
signal.signal(signal.SIGTERM, self._on_signal_term)
if (hasattr(self, "channel") and self.channel):
self.timer = RepeatingTimer(self.period,
lambda: self.evaluate(**kwargs))
self.timer.start()
self.channel.connect(**kwargs)
def _on_signal_term(self, signum, frame):
LOG.info('Received signal: %s' % signum)
self.disconnect()
def disconnect(self, **kwargs):
LOG.info('Disconnecting %s' % self.id)
if (hasattr(self, "timer") and self.timer):
self.timer.stop()
if (hasattr(self, "channel") and self.channel):
if "reason" in kwargs.keys():
LOG.info("Disconnected with reason: %s" % kwargs['reason'])
self.channel.stop(**kwargs)
if (hasattr(self, "clean") and callable(self.clean)):
self.clean()
def evaluate(self, *args, **kwargs):
if not self.eval_func:
return
for (sender, values) in self.queue.items():
self.clean_queue_values(values, **kwargs)
eval_value = self.eval_func(values.values())
if eval_value >= self.threshold:
if not self.fired:
# Fire if not already fired
self.fired = True
self.fire(sender, eval_value)
else:
self.fired = False
def preprocess(self, data, **kwargs):
return data
def on_update(self, sender, data, **kwargs):
LOG.info("Received data from %s:[%s] : %s" % (self.id,
sender,
data))
self.queue.setdefault(sender,
{})[datetime.now()] = self.preprocess(data,
**kwargs)
def fire(self, sender, eval_value, *args, **kwargs):
raise NotImplementedError("This should be implemented in parent class")
def clean_queue_values(self, values, **kwargs):
"""
Performs a default clean, assuming the keys are timestamp values
"""
keys = sorted(values.keys())
for timestamp in keys:
if (datetime.now() - timestamp).seconds > self.period:
values.pop(timestamp)
else:
break
def escalate(self, sender, receiver, data):
# Used to escalate decision result to another queue
try:
if self.channel.queue:
self.channel.queue.escalate(sender, receiver, unicode(data))
else:
LOG.warn("No queue found to escalate %s %s %s" % (sender,
receiver,
data))
except Exception, ex:
LOG.exception(ex)