50 lines
1.3 KiB
Python
50 lines
1.3 KiB
Python
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import logging
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import json
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import os
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import time
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from .. import Backend
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class LocalBackend(Backend):
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def _init(self, fifo):
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self.fifo = fifo
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try: os.mkfifo(self.fifo)
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except FileExistsError as e: pass
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logging.info('Initialized local backend on fifo {}'.format(self.fifo))
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def send_msg(self, msg):
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if isinstance(msg, dict):
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msg = json.dumps(msg)
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if not isinstance(msg, str):
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msg = json.dumps(msg)
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raise RuntimeError('Invalid non-JSON message')
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msglen = len(msg)+1 # Include \n
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msg = bytearray((str(msglen) + '\n' + msg + '\n').encode('utf-8'))
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with open(self.fifo, 'wb') as f:
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f.write(msg)
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def run(self):
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with open(self.fifo, 'rb', 0) as f:
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while True:
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try:
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msglen = int(f.readline())
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except ValueError as e:
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time.sleep(0.1)
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continue
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msg = f.read(msglen-1)
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if not msg: continue
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try:
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msg = json.loads(msg.decode('utf-8'))
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except Exception as e:
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logging.exception(e)
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continue
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logging.debug('Received message: {}'.format(msg))
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self.on_msg(msg)
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# vim:sw=4:ts=4:et:
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