only check channel availability if using the dispatcher, i.e., if there is no host configured

bstrd/bscache.py

@@ -73,7 +73,8 @@ class BSCache:
         new_chans = {}
         for name, kwargs in names.items():
             if name not in FIXED_CHANNELS and name not in self.channels:
-                check_availability(name)
+                if self.uses_dispatcher:
+                    check_availability(name)
                 cfg = make_channel_config(name, *kwargs)
                 new_chans[name] = cfg
 
@@ -86,7 +87,8 @@ class BSCache:
 
     def get_var(self, name, modulo=None, offset=None):
         if name not in FIXED_CHANNELS and name not in self.channels:
-            check_availability(name)
+            if self.uses_dispatcher:
+                check_availability(name)
             cfg = make_channel_config(name, modulo, offset)
             print("add new channel", name)
             self.add_var(name, cfg)
@@ -122,6 +124,10 @@ class BSCache:
     def flush(self):
         self.pt.queue.clear()
 
+    @property
+    def uses_dispatcher(self):
+        return bool(self.kwargs["host"])
+
 
 
 def check_availability(name):