Set fabric label on interview

Instead of setting the label on commissioning only, set it during the
interview process but only if necessary. This avoids the commissioning
process to fail in a incomplete state when setting the label fails.

The interview process has more resilience to recover from a failure
during the commissioning since we have a retry mechanism in place.

This also allows to set the label on devices that are already
commissioned.

Also (try to) unpair the device in case interviewing fails. This allows
user to commission a second time without running into "Trying to add a
NOC for a fabric that already exists" errors.

Author: agners

matter_server/server/device_controller.py

@@ -321,15 +321,6 @@ async def commission_with_code(
             LOGGER.info("Commissioned Node ID: %s vs %s", commissioned_node_id, node_id)
             if commissioned_node_id != node_id:
                 raise RuntimeError("Returned Node ID must match requested Node ID")
-
-            if self._default_fabric_label:
-                await self._chip_device_controller.send_command(
-                    node_id,
-                    0,
-                    Clusters.OperationalCredentials.Commands.UpdateFabricLabel(
-                        self._default_fabric_label
-                    ),
-                )
         except ChipStackError as err:
             raise NodeCommissionFailed(
                 f"Commission with code failed for node {node_id}."
@@ -348,6 +339,12 @@ async def commission_with_code(
                 await self._interview_node(node_id)
             except (NodeNotResolving, NodeInterviewFailed) as err:
                 if retries <= 0:
+                    try:
+                        await self._chip_device_controller.unpair_device(node_id)
+                    except ChipStackError as err_unpair:
+                        LOGGER.warning(
+                            "Removing current fabric from device failed: %s", err_unpair
+                        )
                     raise err
                 retries -= 1
                 LOGGER.warning("Unable to interview Node %s: %s", node_id, err)
@@ -580,6 +577,39 @@ async def _interview_node(self, node_id: int) -> None:
         except ChipStackError as err:
             raise NodeInterviewFailed(f"Failed to interview node {node_id}") from err
 
+        # Set label if specified and needed
+        if self._default_fabric_label:
+            cluster = read_response.attributes[0][Clusters.OperationalCredentials]
+            fabrics: list[
+                Clusters.OperationalCredentials.Structs.FabricDescriptorStruct
+            ] = cluster[Clusters.OperationalCredentials.Attributes.Fabrics]
+            fabric_index = cluster[
+                Clusters.OperationalCredentials.Attributes.CurrentFabricIndex
+            ]
+
+            local_fabric = next(
+                (fabric for fabric in fabrics if fabric.fabricIndex == fabric_index),
+                None,
+            )
+            if local_fabric and local_fabric.label != self._default_fabric_label:
+                try:
+                    LOGGER.debug(
+                        "Setting fabric label for node %s to '%s'",
+                        node_id,
+                        self._default_fabric_label,
+                    )
+                    await self._chip_device_controller.send_command(
+                        node_id,
+                        0,
+                        Clusters.OperationalCredentials.Commands.UpdateFabricLabel(
+                            self._default_fabric_label
+                        ),
+                    )
+                except ChipStackError as err:
+                    LOGGER.warning(
+                        "Failed to set fabric label for node %s: %s", node_id, err
+                    )
+
         is_new_node = node_id not in self._nodes
         existing_info = self._nodes.get(node_id)
         node = MatterNodeData(