New time slicing considering empty cluster subsets

Empty cluster subsets are still stored as empty list ie. size=0

src/data-hub/role-stage-discovery-microservice/app/db/entities/timeslice.py

@@ -23,12 +23,20 @@ class TimeSlice:
         if time_slice_dict is not None:
             self.from_serializable_dict(time_slice_dict, from_db)
 
+    def init_all_clusters(self, cluster_labels: List[str]):
+        '''Initializes internal clusters for all labels with an empty list.'''
+        for cluster_label in cluster_labels:
+            # only string keys can be stored in json
+            cluster_label = str(cluster_label)
+            self.clusters[cluster_label] = []
+
     def add_node_to_cluster(self, cluster_label: str, node):
         # only string keys can be stored in json
         cluster_label = str(cluster_label)
 
         if cluster_label not in self.clusters:
-            self.clusters[cluster_label] = []
+            # self.clusters[cluster_label] = []
+            raise KeyError(f"self::init_all_clusters must be used to add all global cluster labels beforehand (got {cluster_label})")
 
         # node = self._get_unique_id(node)
         self.clusters[cluster_label].append(node)

src/data-hub/role-stage-discovery-microservice/app/run_time_slicing.py

@@ -38,14 +38,16 @@ def split_clusterset_by_time(layer: Layer, clusters: List[Cluster]) -> Dict[Time
     '''
 
     time_slices: Dict[Any, TimeSlice] = {} 
-    for cluster_no in clusters:
-        if cluster_no.cluster_label == -1:
+    all_cluster_labels = [cluster.cluster_label for cluster in clusters if cluster.cluster_label != -1]
+
+    for cluster in clusters:
+        if cluster.cluster_label == -1:
             print("Noise cluster was ignored.")
             continue
 
-        for node in cluster_no.nodes:
+        for node in cluster.nodes:
 
-            # retrieve times the node is located in based on the defined time properties in the schema
+            # retrieve times where the node is located inas (year, week), based on the defined timestamp fields in the schema
             time_keys = set()
             for time_property in TIME_PROPERTY_NAMES:
                 if time_property in node:
@@ -54,8 +56,9 @@ def split_clusterset_by_time(layer: Layer, clusters: List[Cluster]) -> Dict[Time
             for time_key in time_keys:
                 if time_key not in time_slices:
                     time_slices[time_key] = TimeSlice(time_key, layer.use_case, layer.use_case_table, layer.layer_name)
+                    time_slices[time_key].init_all_clusters(all_cluster_labels)
 
-                time_slices[time_key].add_node_to_cluster(cluster_no.cluster_label, node)
+                time_slices[time_key].add_node_to_cluster(cluster.cluster_label, node)
 
     return time_slices