From 108061111f2fada9ffd43ba2293cd706e636e2d3 Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@agner.ch>
Date: Tue, 21 Jun 2022 19:49:57 -0700
Subject: [PATCH] Add Error Callback for subscriptions (#19693)

This is useful when subscriptions are not renewed automatically to get
the actual error from the stack.

Without this change, if auto-renew is disabled, the following exception
is thrown:
ERROR Exception in callback AsyncReadTransaction._handleError(50)
handle: <Handle AsyncReadTransaction._handleError(50)>
Traceback (most recent call last):
  File "/usr/lib/python3.9/asyncio/events.py", line 80, in _run
    self._context.run(self._callback, *self._args)
  File "/home/sag/projects/project-chip/connectedhomeip/out/python_env/lib/python3.9/site-packages/chip/clusters/Attribute.py", line 661, in _handleError
    self._future.set_exception(
asyncio.exceptions.InvalidStateError: invalid state
---
 .../python/chip/clusters/Attribute.py         | 22 +++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/controller/python/chip/clusters/Attribute.py b/src/controller/python/chip/clusters/Attribute.py
index a70f49dda601e7..07ae05a6b0ebf4 100644
--- a/src/controller/python/chip/clusters/Attribute.py
+++ b/src/controller/python/chip/clusters/Attribute.py
@@ -468,6 +468,7 @@ class SubscriptionTransaction:
     def __init__(self, transaction: 'AsyncReadTransaction', subscriptionId, devCtrl):
         self._onAttributeChangeCb = DefaultAttributeChangeCallback
         self._onEventChangeCb = DefaultEventChangeCallback
+        self._onErrorCb = DefaultErrorCallback
         self._readTransaction = transaction
         self._subscriptionId = subscriptionId
         self._devCtrl = devCtrl
@@ -502,6 +503,13 @@ def SetEventUpdateCallback(self, callback: Callable[[EventReadResult, Subscripti
         if callback is not None:
             self._onEventChangeCb = callback
 
+    def SetErrorCallback(self, callback: Callable[[int, SubscriptionTransaction], None]):
+        '''
+        Sets the callback function in case a subscription error occured, accepts a Callable accepts an error code and the cached data.
+        '''
+        if callback is not None:
+            self._onErrorCb = callback
+
     @property
     def OnAttributeChangeCb(self) -> Callable[[TypedAttributePath, SubscriptionTransaction], None]:
         return self._onAttributeChangeCb
@@ -510,6 +518,10 @@ def OnAttributeChangeCb(self) -> Callable[[TypedAttributePath, SubscriptionTrans
     def OnEventChangeCb(self) -> Callable[[EventReadResult, SubscriptionTransaction], None]:
         return self._onEventChangeCb
 
+    @property
+    def OnErrorCb(self) -> Callable[[int, SubscriptionTransaction], None]:
+        return self._onErrorCb
+
     def Shutdown(self):
         if (self._isDone):
             print("Subscription was already terminated previously!")
@@ -545,6 +557,10 @@ def DefaultEventChangeCallback(data: EventReadResult, transaction: SubscriptionT
     pprint(data, expand_all=True)
 
 
+def DefaultErrorCallback(chipError: int, transaction: SubscriptionTransaction):
+    print("Error during Subscription: Chip Stack Error %d".format(chipError))
+
+
 def _BuildEventIndex():
     ''' Build internal event index for locating the corresponding cluster object by path in the future.
     We do this because this operation will take a long time when there are lots of events, it takes about 300ms for a single query.
@@ -659,8 +675,10 @@ def handleEventData(self, header: EventHeader, path: EventPath, data: bytes, sta
         self._handleEventData(header, path, data, status)
 
     def _handleError(self, chipError: int):
-        self._future.set_exception(
-            chip.exceptions.ChipStackError(chipError))
+        if not self._future.done():
+            self._future.set_exception(
+                chip.exceptions.ChipStackError(chipError))
+        self._subscription_handler.OnErrorCb(chipError, self._subscription_handler)
 
     def handleError(self, chipError: int):
         self._event_loop.call_soon_threadsafe(