def _init_controlhost(self):
"""Set up the controlhost connection"""
from controlhost import Client
self.client = Client(self.host, self.port)
self.client._connect()
for tag in self.tags.split(','):
self.client.subscribe(tag.strip())
class CHPump(Pump):
"""A pump for ControlHost data."""
def __init__(self, **context):
super(self.__class__, self).__init__(**context)
self.host = self.get('host') or '127.0.0.1'
self.port = self.get('port') or 5553
self.tags = self.get('tags') or "MSG"
self.timeout = self.get('timeout') or 60*60*24
self.max_queue = self.get('max_queue') or 50
self.key_for_data = self.get('key_for_data') or 'CHData'
self.key_for_prefix = self.get('key_for_prefix') or 'CHPrefix'
self.queue = Queue()
self.client = None
self.thread = None
print("Connecting to {0} on port {1}\n"
"Subscribed tags: {2}\n"
"Connection timout: {3}s\n"
"Maximum queue size for incoming data: {4}"
.format(self.host, self.port, self.tags, self.timeout,
self.max_queue))
self._init_controlhost()
self._start_thread()
def _start_thread(self):
self.thread = threading.Thread(target=self._run, args=())
self.thread.daemon = True
self.thread.start()
def _init_controlhost(self):
"""Set up the controlhost connection"""
from controlhost import Client
self.client = Client(self.host, self.port)
self.client._connect()
for tag in self.tags.split(','):
self.client.subscribe(tag.strip())
def _run(self):
while True:
prefix, data = self.client.get_message()
if self.queue.qsize() > self.max_queue:
log.warn("Maximum queue size ({0}) reached, dropping data."
.format(self.max_queue))
else:
self.queue.put((prefix, data))
def process(self, blob):
"""Wait for the next packet and put it in the blob"""
try:
prefix, data = self.queue.get(timeout=self.timeout)
except Empty:
log.warn("ControlHost timeout ({0}s) exceeded".format(self.timeout))
raise StopIteration("ControlHost timeout exceeded.")
blob[self.key_for_prefix] = prefix
blob[self.key_for_data] = data
return blob
def finish(self):
"""Clean up the JLigier controlhost connection"""
self.client._disconnect()
