DetectorAssembler: go to ERROR if trying to match without geometry

#48 (closed) this came up again recently, let's do something about it.

• geometry is a property again, so if geometry device is up, we don't even need to wait for signal to get it
• DRY a bit by putting utility to get property + connect to signal in calngUtils
• start warning harder if no geometry

Options:

1. stay in INIT until we get geometry
2. go to ERROR after some timeout if we don't get geometry
3. go to ERROR in match handler if we don't have geometry by the time we need it (current implementation)

As the diff shows, at least for option 3, we need to fight the TrainMatcher state logic a bit; it's going from PASSIVE to CHANGING to ACTIVE outside of the methods we're currently overriding. State transitions for an assembler started while geometry device is down and then geometry device comes up later:

src/calng/DetectorAssembler.py

@@ -20,7 +20,6 @@ from karabo.bound import (
     ImageData,
     MetricPrefix,
     Schema,
-    State,
     Timestamp,
     Trainstamp,
     Unit,
@@ -150,6 +149,19 @@ class DetectorAssembler(TrainMatcher.TrainMatcher):
             .assignmentMandatory()
             .commit(),
 
+            STRING_ELEMENT(expected)
+            .key("geometryState")
+            .displayedName("Geometry state")
+            .description(
+                "The assembler needs a detector geometry to function. This is gotten "
+                "from a geometry device (see the geometryDevice parameter). If this "
+                "state is ERROR, no assembly will take place - check the geometry "
+                "device!"
+            )
+            .readOnly()
+            .initialValue("INIT")
+            .commit(),
+
             STRING_ELEMENT(expected)
             .key("sourceIndexPattern")
             .displayedName("Source index regex")
@@ -209,16 +221,16 @@ class DetectorAssembler(TrainMatcher.TrainMatcher):
         self._geometry = None
         def _on_geometry(geometry):
             if self._geometry is None:
-                # TODO: review with new warning system
-                if hasattr(self, "_state_before_geometry_missing_error"):
-                    self.set("status", "Received geometry!")
-                    self.updateState(self._state_before_geometry_missing_error)
-                    del self._state_before_geometry_missing_error
+                self.set("geometryState", "ACTIVE")
             self._geometry = geometry
             self.log.INFO("Received new geometry")
         geom_utils.subscribe_to_geometry_bound(
-            self, self.get("geometryDevice"), _on_geometry, warn_fun=self.log.WARN
+            self, self.get("geometryDevice"), _on_geometry
         )
+        print("done setting up thing", self._geometry)
+        if self._geometry is None:
+            # initial get failed
+            self.set("geometryState", "ERROR")
 
         self.assembled_output = self.signalSlotable.getOutputChannel("assembledOutput")
         self.start()
@@ -362,6 +374,7 @@ class DetectorAssembler(TrainMatcher.TrainMatcher):
         payload["data"] = scenes.detector_assembler_overview(
             device_id=self.getInstanceId(),
             schema=self.getFullSchema(),
+            geometry_device_id=self.get("geometryDevice"),
         )
         self.reply(
             Hash(
@@ -376,21 +389,9 @@ class DetectorAssembler(TrainMatcher.TrainMatcher):
 
     def on_matched_data(self, train_id, sources):
         ts_start = default_timer()
-        state = self.get("state")
 
         if self._geometry is None:
-            if not hasattr(self, "_state_before_geometry_missing_error"):
-                self.log.WARN("Have not received a geometry yet, will not send anything")
-                self.set(
-                    "status",
-                    "Missing geometry, cannot assemble; "
-                    f"check {self.get('geometryDevice')}"
-                )
-
-            if state is not State.ERROR:
-                self.updateState(State.ERROR)
-                # set or update
-                self._state_before_geometry_missing_error = state
+            # should have already set up warning
             return
 
         my_timestamp = Timestamp(Epochstamp(), Trainstamp(train_id))