ucloud: Simplify the build_dict and add_to_pack logic.

* Add arg to set if records are added to a pack to be pushed to or updated
from the cloud.
* When adding records to be pushed to the cloud, only initialized records
are added. When adding records to be updated from the cloud, uninitialized
records are allowed to be initialized from the cloud.

Author: iabdalkader

arduino_iot_cloud/ucloud.py

@@ -129,27 +129,33 @@ def __setattr__(self, attr, value):
             super().__setattr__(attr, value)
 
     def _build_rec_dict(self, naming_map, appendTo):
+        # This function builds a dict of records from a pack, which gets converted to CBOR and
+        # pushed to the cloud on the next update.
         if isinstance(self.value, dict):
             for r in self.value.values():
-                if r.value is not None:  # NOTE: should filter by updated when it's supported.
-                    r._build_rec_dict(naming_map, appendTo)
-        elif self._value is not None:
+                r._build_rec_dict(naming_map, appendTo)
+        else:
             super()._build_rec_dict(naming_map, appendTo)
 
-    def add_to_pack(self, pack):
+    def add_to_pack(self, pack, push=False):
+        # This function adds records that will be pushed to (or updated from) the cloud, to the SenML pack.
+        # NOTE: When adding records to be pushed to the cloud (push=True) Only initialized records are added
+        # to the pack. And when adding records to be updated from the cloud (push=False), records whose values
+        # are None are allowed to be added to the pack, so they can be initialized from the cloud.
+        # NOTE: all initialized sub-records are added to the pack whether they changed their state since the
+        # last update or not, because the cloud currently does not support partial objects updates.
         if isinstance(self.value, dict):
             for r in self.value.values():
-                # NOTE: If record value is None it can still be added to the pack for initialization.
-                pack.add(r)  # NOTE: should filter by updated when it's supported.
-        else:
+                if r._value is not None or (r._value is None and not push):
+                    pack.add(r)
+        elif self._value is not None or (self._value is None and not push):
             pack.add(self)
         self.updated = False
 
     def senml_callback(self, record, **kwargs):
-        """
-        This is called after the record is updated from the cloud. Clear the updated flag to
-        avoid sending the same value back to the cloud, and schedule the on_write callback.
-        """
+        # This function gets called after a record is updated from the cloud (from_cbor).
+        # The updated flag is cleared to avoid sending the same value again to the cloud,
+        # and the on_write function flag is set to so it gets called on the next run.
         self.updated = False
         self.on_write_scheduled = True
 
@@ -235,9 +241,7 @@ def register(self, aiotobj, **kwargs):
             self.register("r:m", value="getLastValues")
 
     def senml_generic_callback(self, record, **kwargs):
-        """
-        This callback catches all unknown/umatched records that were not part the pack.
-        """
+        # This callback catches all unknown/umatched sub/records that were not part of the pack.
         rname, sname = record.name.split(":") if ":" in record.name else [record.name, None]
         if rname in self.records:
             logging.debug(f"Ignoring cloud initialization for record: {record.name}")
@@ -278,7 +282,7 @@ async def mqtt_task(self, interval=0.100):
                 self.senmlpack.clear()
                 for record in self.records.values():
                     if record.updated:
-                        record.add_to_pack(self.senmlpack)
+                        record.add_to_pack(self.senmlpack, push=True)
                 if len(self.senmlpack._data):
                     logging.debug("Pushing records to Arduino IoT cloud:")
                     for record in self.senmlpack: