115 lines
4.4 KiB
Python
115 lines
4.4 KiB
Python
#!/usr/bin/env python
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import datetime
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from communicator import Communicator
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import os
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"""
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Consumer locator module, that manages the list of consumers.
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"""
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__author__ = "@dscharnitzky"
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__copyright__ = "Copyright 2020, GoldenPogácsa Team"
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__module_name__ = "consumerlocator"
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__version__text__ = "1"
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KNOWNCONSUMER = os.getenv("PRODUCER_KNOWNCONSUMER",'10.69.42.1')
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class ConsumerLocator:
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"""
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Component responsible for managing the list of consumers. Requires an instance of :class:'communicator.Communicator'
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"""
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def __init__(self, uuid: str, communicator: Communicator):
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"""Initializes the object.
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Gets the known consumer's IP address from the PRODUCER_KNOWNCONSUMER envar.
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:param: uuid: Not used
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:param: communicator: the :class:'communicator.Communicator' instance that will be used for the low level
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communication.
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"""
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self.consumerlist = [{"Host": KNOWNCONSUMER, "State": True, "LastOk": datetime.datetime.now()}]
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self.currentconsumer = self.consumerlist[0]
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self.communicator = communicator
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def learnconsumerlist(self) -> None:
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""""Learns the list of consumers from the current consumer.
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Calls :func:'~communicator.Communicator.didiscoveravailableconsumers', adds the learned consumers to the list
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if are not present, and then calls :func:'~consumerlocator.ConsumerLocator.updateconsumerlist'
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:return: None
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"""
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recievedconsumerlist = self.communicator.discoveravailableconsumers()
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if recievedconsumerlist is None:
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return
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for recconsumer in recievedconsumerlist:
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contains = False
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for consumer in self.consumerlist:
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if consumer["Host"] == recconsumer:
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contains = True
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if not contains:
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self.consumerlist.append({"Host": recconsumer, "State": True, "LastOk": datetime.datetime.now()})
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self.updateconsumerlist()
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def updateconsumerlist(self) -> None:
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""" Updates the consumer list based on their availability.
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Marks for each consumer if they are available or not. If a consumer is not available for some time (1 hour),
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the it will be deleted from the list.
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:return: None
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"""
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removelist = []
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for consumer in self.consumerlist:
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if not self.communicator.checkconsumer(consumer["Host"]):
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consumer["State"] = False
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if datetime.datetime.now() - consumer["LastOk"] > datetime.timedelta(hours=1):
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removelist.append(consumer)
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else:
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consumer["LastOk"] = datetime.datetime.now()
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consumer["State"] = True
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for rem in removelist:
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self.consumerlist.remove(rem)
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def updateconsumer(self):
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"""If the current consumer is not available, checks all the consumers in the list and updates the current one.
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Calls :func:'~consumerlocator.ConsumerLocator.checkcurrentconsumer' and if needed
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:func:'~consumerlocator.ConsumerLocator.updateconsumerlist'. Sets the :class:'communicator.Communicator'
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current instance with :func:'~communicator.Communicator.set_currentconsumer'.
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:return: the current consumer or None if there are no available customers at the moment.
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"""
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if not self.checkcurrentconsumer():
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self.updateconsumerlist()
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newcurrentconsumer = None
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for consumer in self.consumerlist:
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if consumer["State"]:
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newcurrentconsumer = consumer
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break
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self.currentconsumer = newcurrentconsumer
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if self.currentconsumer is not None:
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self.learnconsumerlist()
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if self.currentconsumer is not None:
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self.communicator.set_currentconsumer(self.currentconsumer["Host"])
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return self.currentconsumer["Host"]
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else:
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return None
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def getcurrentconsumer(self) -> str:
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"""
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Returns the currently selected consumer's IP address.
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:return: the current consumer
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"""
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return self.currentconsumer["Host"]
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def checkcurrentconsumer(self) -> bool:
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"""
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Check the current consumer's health.
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:return: True if OK, False if fail
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"""
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if self.currentconsumer is None:
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return False
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return self.communicator.checkconsumer(self.currentconsumer["Host"])
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