From 26a57c9d6f2b69a4b5f67710dacf3c367b340ffc Mon Sep 17 00:00:00 2001 From: Fabio Manganiello Date: Fri, 20 Jul 2018 15:54:27 +0200 Subject: [PATCH] Preventing inconsistent reads from the serial port by making sure that only one reader can read at the time --- platypush/plugins/serial/__init__.py | 37 +++++++++++++++++++--------- 1 file changed, 26 insertions(+), 11 deletions(-) diff --git a/platypush/plugins/serial/__init__.py b/platypush/plugins/serial/__init__.py index dbd7694dc..075b10e83 100644 --- a/platypush/plugins/serial/__init__.py +++ b/platypush/plugins/serial/__init__.py @@ -1,5 +1,6 @@ import json import serial +import threading import time from platypush.plugins import Plugin, action @@ -30,6 +31,8 @@ class SerialPlugin(GpioSensorPlugin): self.device = device self.baud_rate = baud_rate self.serial = None + self.serial_lock = threading.Lock() + self.last_measurement = None def _read_json(self, serial_port): @@ -86,19 +89,31 @@ class SerialPlugin(GpioSensorPlugin): Reads JSON data from the serial device and returns it as a message """ - try: - ser = self._get_serial() - except: - time.sleep(1) - ser = self._get_serial(reset=True) - - data = self._read_json(ser) + data = None try: - data = json.loads(data) - except: - self.logger.warning('Invalid JSON message from {}: {}'. - format(self.device, data)) + serial_available = self.serial_lock.acquire(timeout=2) + if serial_available: + try: + ser = self._get_serial() + except: + time.sleep(1) + ser = self._get_serial(reset=True) + + data = self._read_json(ser) + + try: + data = json.loads(data) + except: + self.logger.warning('Invalid JSON message from {}: {}'. + format(self.device, data)) + else: + data = self.last_measurement + finally: + self.serial_lock.release() + + if data: + self.last_measurement = data return data