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Preventing inconsistent reads from the serial port by making sure that only one reader can read at the time

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This commit is contained in:
Fabio Manganiello 2018-07-20 15:54:27 +02:00
parent 0b4cfec8e7
commit 26a57c9d6f
1 changed files with 26 additions and 11 deletions
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15
platypush/plugins/serial/__init__.py
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@ -1,5 +1,6 @@
import json import json
import serial import serial
import threading
import time import time
from platypush.plugins import Plugin, action from platypush.plugins import Plugin, action
@ -30,6 +31,8 @@ class SerialPlugin(GpioSensorPlugin):
self.device = device self.device = device
self.baud_rate = baud_rate self.baud_rate = baud_rate
self.serial = None self.serial = None
self.serial_lock = threading.Lock()
self.last_measurement = None
def _read_json(self, serial_port): def _read_json(self, serial_port):
@ -86,6 +89,11 @@ class SerialPlugin(GpioSensorPlugin):
Reads JSON data from the serial device and returns it as a message Reads JSON data from the serial device and returns it as a message
""" """
data = None
try:
serial_available = self.serial_lock.acquire(timeout=2)
if serial_available:
try: try:
ser = self._get_serial() ser = self._get_serial()
except: except:
@ -99,6 +107,13 @@ class SerialPlugin(GpioSensorPlugin):
except: except:
self.logger.warning('Invalid JSON message from {}: {}'. self.logger.warning('Invalid JSON message from {}: {}'.
format(self.device, data)) format(self.device, data))
else:
data = self.last_measurement
finally:
self.serial_lock.release()
if data:
self.last_measurement = data
return data return data