improve sdr failure detection

owrx/connection.py

@@ -158,7 +158,7 @@ class OpenWebRxReceiverClient(Client):
         next = SdrService.getSource(id)
 
         if next is None:
-            self.handleSdrFailure("sdr device failed")
+            self.handleSdrFailure("sdr device unavailable")
             return
 
         if next == self.sdr:
@@ -207,7 +207,7 @@ class OpenWebRxReceiverClient(Client):
         self.write_sdr_error(message)
 
     def startDsp(self):
-        if self.dsp is None:
+        if self.dsp is None and self.sdr is not None:
             self.dsp = DspManager(self, self.sdr)
             self.dsp.start()
 

owrx/service.py

@@ -110,9 +110,9 @@ class Schedule(object):
 class ServiceScheduler(object):
     def __init__(self, source, schedule):
         self.source = source
+        self.selectionTimer = None
         self.schedule = Schedule.parse(schedule)
         self.source.addClient(self)
-        self.selectionTimer = None
         self.source.getProps().collect("center_freq", "samp_rate").wire(self.onFrequencyChange)
         self.scheduleSelection()
 

owrx/source/__init__.py

@@ -190,7 +190,11 @@ class SdrSource(object):
         if not available:
             self.failed = True
 
-        self.postStart()
+        try:
+            self.postStart()
+        except Exception:
+            logger.exception("Exception during postStart()")
+            self.failed = True
 
         self.modificationLock.release()