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88 lines
2.4 KiB
88 lines
2.4 KiB
"""Provide service that scans the network in intervals."""
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import logging
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import threading
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import time
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from collections import defaultdict
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from .discovery import NetworkDiscovery
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DEFAULT_INTERVAL = 300 # seconds
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_LOGGER = logging.getLogger(__name__)
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class DiscoveryService(threading.Thread):
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"""Service that will scan the network for devices each `interval` seconds.
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Add listeners to the service to be notified of new services found.
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"""
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def __init__(self, interval=DEFAULT_INTERVAL):
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"""Initialize the discovery."""
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super(DiscoveryService, self).__init__()
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# Scanning interval
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self.interval = interval
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# Listeners for new services
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self.listeners = []
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# To track when we have to stop
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self._stop = threading.Event()
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# Tell Python not to wait till this thread exits
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self.daemon = True
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# The discovery object
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self.discovery = None
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# Dict to keep track of found services. We do not want to
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# broadcast the same found service twice.
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self._found = defaultdict(list)
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def add_listener(self, listener):
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"""Add a listener for new services."""
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self.listeners.append(listener)
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def stop(self):
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"""Stop the service."""
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self._stop.set()
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def run(self):
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"""Start the discovery service."""
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self.discovery = NetworkDiscovery()
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while True:
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self._scan()
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seconds_since_scan = 0
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while seconds_since_scan < self.interval:
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if self._stop.is_set():
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return
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time.sleep(1)
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seconds_since_scan += 1
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def _scan(self):
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"""Scan for new devices."""
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_LOGGER.info("Scanning")
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self.discovery.scan()
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for disc in self.discovery.discover():
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for service in self.discovery.get_info(disc):
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self._service_found(disc, service)
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self.discovery.stop()
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def _service_found(self, disc, service):
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"""Tell listeners a service was found."""
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if service not in self._found[disc]:
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self._found[disc].append(service)
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for listener in self.listeners:
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try:
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listener(disc, service)
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except Exception: # pylint: disable=broad-except
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_LOGGER.exception(
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"Error calling listener")
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