applets: Allow wildcard subscription to all datasets matching prefix via IPC

This allows ndscan v0.3+ to use the IPC interface for efficiency;
previously, the non-upstreamed RID dataset namespace feature allowed
the applets to somewhat efficient subscribe directly to the master
process via the socket interface.

artiq/applets/simple.py

@@ -64,9 +64,10 @@ class AppletIPCClient(AsyncioChildComm):
                              exc_info=True)
                 self.close_cb()
 
-    def subscribe(self, datasets, init_cb, mod_cb):
+    def subscribe(self, datasets, init_cb, mod_cb, dataset_prefixes=[]):
         self.write_pyon({"action": "subscribe",
-                         "datasets": datasets})
+                         "datasets": datasets,
+                         "dataset_prefixes": dataset_prefixes})
         self.init_cb = init_cb
         self.mod_cb = mod_cb
         asyncio.ensure_future(self.listen())
@@ -113,6 +114,9 @@ class SimpleApplet:
         self.embed = os.getenv("ARTIQ_APPLET_EMBED")
         self.datasets = {getattr(self.args, arg.replace("-", "_"))
                          for arg in self.dataset_args}
+        # Optional prefixes (dataset sub-trees) to match subscriptions against;
+        # currently only used by out-of-tree subclasses (ndscan).
+        self.dataset_prefixes = []
 
     def qasync_init(self):
         app = QtWidgets.QApplication([])
@@ -162,6 +166,14 @@ class SimpleApplet:
         self.data = data
         return data
 
+    def is_dataset_subscribed(self, key):
+        if key in self.datasets:
+            return True
+        for prefix in self.dataset_prefixes:
+            if key.startswith(prefix):
+                return True
+        return False
+
     def filter_mod(self, mod):
         if self.embed is not None:
             # the parent already filters for us
@@ -170,9 +182,9 @@ class SimpleApplet:
         if mod["action"] == "init":
             return True
         if mod["path"]:
-            return mod["path"][0] in self.datasets
+            return self.is_dataset_subscribed(mod["path"][0])
         elif mod["action"] in {"setitem", "delitem"}:
-            return mod["key"] in self.datasets
+            return self.is_dataset_subscribed(mod["key"])
         else:
             return False
 

artiq/gui/applets.py

@@ -25,6 +25,7 @@ class AppletIPCServer(AsyncioParentComm):
         AsyncioParentComm.__init__(self)
         self.datasets_sub = datasets_sub
         self.datasets = set()
+        self.dataset_prefixes = []
 
     def write_pyon(self, obj):
         self.write(pyon.encode(obj).encode() + b"\n")
@@ -33,8 +34,16 @@ class AppletIPCServer(AsyncioParentComm):
         line = await self.readline()
         return pyon.decode(line.decode())
 
+    def _is_dataset_subscribed(self, key):
+        if key in self.datasets:
+            return True
+        for prefix in self.dataset_prefixes:
+            if key.startswith(prefix):
+                return True
+        return False
+
     def _synthesize_init(self, data):
-        struct = {k: v for k, v in data.items() if k in self.datasets}
+        struct = {k: v for k, v in data.items() if self._is_dataset_subscribed(k)}
         return {"action": "init",
                 "struct": struct}
 
@@ -43,10 +52,10 @@ class AppletIPCServer(AsyncioParentComm):
             mod = self._synthesize_init(mod["struct"])
         else:
             if mod["path"]:
-                if mod["path"][0] not in self.datasets:
+                if not self._is_dataset_subscribed(mod["path"][0]):
                     return
             elif mod["action"] in {"setitem", "delitem"}:
-                if mod["key"] not in self.datasets:
+                if not self._is_dataset_subscribed(mod["key"]):
                     return
         self.write_pyon({"action": "mod", "mod": mod})
 
@@ -64,6 +73,7 @@ class AppletIPCServer(AsyncioParentComm):
                         fix_initial_size_cb()
                     elif action == "subscribe":
                         self.datasets = obj["datasets"]
+                        self.dataset_prefixes = obj["dataset_prefixes"]
                         if self.datasets_sub.model is not None:
                             mod = self._synthesize_init(
                                 self.datasets_sub.model.backing_store)