make decoding queue settings work from the web config

owrx/audio.py

@@ -46,7 +46,7 @@ class QueueWorker(threading.Thread):
         while self.doRun:
             job = self.queue.get()
             if job is PoisonPill:
-                self.doRun = False
+                self.stop()
             else:
                 try:
                     job.run()
@@ -58,6 +58,9 @@ class QueueWorker(threading.Thread):
 
             self.queue.task_done()
 
+    def stop(self):
+        self.doRun = False
+
 
 class DecoderQueue(Queue):
     sharedInstance = None
@@ -67,10 +70,7 @@ class DecoderQueue(Queue):
     def getSharedInstance():
         with DecoderQueue.creationLock:
             if DecoderQueue.sharedInstance is None:
-                pm = Config.get()
-                DecoderQueue.sharedInstance = DecoderQueue(
-                    maxsize=pm["decoding_queue_length"], workers=pm["decoding_queue_workers"]
-                )
+                DecoderQueue.sharedInstance = DecoderQueue()
         return DecoderQueue.sharedInstance
 
     @staticmethod
@@ -80,8 +80,15 @@ class DecoderQueue(Queue):
                 DecoderQueue.sharedInstance.stop()
                 DecoderQueue.sharedInstance = None
 
-    def __init__(self, maxsize, workers):
-        super().__init__(maxsize)
+    def __init__(self):
+        pm = Config.get()
+        super().__init__(pm["decoding_queue_length"])
+        self.workers = []
+        self._setWorkers(pm["decoding_queue_workers"])
+        self.subscriptions = [
+            pm.wireProperty("decoding_queue_length", self._setMaxSize),
+            pm.wireProperty("decoding_queue_workers", self._setWorkers),
+        ]
         metrics = Metrics.getSharedInstance()
         metrics.addMetric("decoding.queue.length", DirectMetric(self.qsize))
         self.inCounter = CounterMetric()
@@ -92,10 +99,24 @@ class DecoderQueue(Queue):
         metrics.addMetric("decoding.queue.overflow", self.overflowCounter)
         self.errorCounter = CounterMetric()
         metrics.addMetric("decoding.queue.error", self.errorCounter)
-        self.workers = [self.newWorker() for _ in range(0, workers)]
+
+    def _setMaxSize(self, size):
+        if self.maxsize == size:
+            return
+        self.maxsize = size
+
+    def _setWorkers(self, workers):
+        while len(self.workers) > workers:
+            logger.debug("stopping one worker")
+            self.workers.pop().stop()
+        while len(self.workers) < workers:
+            logger.debug("starting one worker")
+            self.workers.append(self.newWorker())
 
     def stop(self):
         logger.debug("shutting down the queue")
+        while self.subscriptions:
+            self.subscriptions.pop().cancel()
         try:
             # purge all remaining jobs
             while not self.empty():