From 26a57c9d6f2b69a4b5f67710dacf3c367b340ffc Mon Sep 17 00:00:00 2001
From: Fabio Manganiello <blacklight86@gmail.com>
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