add threading async reader. Not recommended for use probably...

src/lib/terkin/driver/vedirect_sensor.py

@@ -2,6 +2,8 @@
 # (c) 2020 Jan Hoffmann <jan.hoffmann@bergamsee.de>
 # (c) 2020 Andreas Motl <andreas.motl@terkin.org>
 # License: GNU General Public License, Version 3
+import time
+import _thread
 from terkin import logging
 from terkin.sensor import SensorManager, AbstractSensor
 from terkin.util import get_platform_info
@@ -55,6 +57,31 @@ def __init__(self, settings=None):
         self.device = settings["device"]
         self.timeout = 5
         self.driver = None
+        self.threading = bool(settings["async"])
+        self._raw_data= None
+        self._read_time = 0
+        self._shutdown = False
+
+    def __del__(self):
+        self.shutdown()
+
+    def shutdown(self):
+        self._shutdown = True
+
+    def _async_read(self):
+        """Read until shutdown"""
+        log.info("Starting async VEDirect thread")
+        while not self._shutdown:
+            try:
+                data = self.driver.read_data_single(timeout=5000)
+                if not data:
+                    continue
+                log.info("Received ASYNC data, storing it")
+                self._raw_data = data
+                self._read_time = time.time()
+            except KeyboardInterrupt:
+                break
+        log.info("Shutting down async VEDirect thread")
 
     def start(self):
         log.info('Initializing sensor "Victron Energy VE.Direct"')
@@ -92,6 +119,11 @@ def start(self):
                     "VEDirect driver not implemented on this platform"
                 )
 
+            if self.threading:
+                # Todo: probably need to use a queue to pass data between threads?
+                _thread.start_new_thread(self._async_read, ())
+                time.sleep(1)  # Allow thread to start up
+                self.timeout = 60  # Since this is async, we can accept a longer timeout
             return True
 
         except Exception as ex:
@@ -103,11 +135,24 @@ def read(self):
             return
         log.info('Reading sensor "Victron Energy VE.Direct"')
 
-        data_raw = self.driver.read_data_single()
-
+        if self.threading:
+            data_raw = self._raw_data
+            if data_raw:
+                if time.time() - self._read_time > self.timeout:
+                    raise TimeoutError("VEDirect Asynchronous reading stale data, not sending")
+            self._raw_data = None
+        else:
+            data_raw = self.driver.read_data_single()
+        if not data_raw:
+            raise ValueError("No data received from VEDirect")
         data = {}
+        product_id = ""
+        if "PID" in data_raw:
+            product_id = str(data_raw["PID"])
+        else:
+            product_id = "unkown-pid"
         for key, value in data_raw.items():
-            key = "vedirect:{}".format(key)
+            key = "vedirect-{}:{}".format(product_id, key)
             data[key] = value
 
         return data