0012-Python-Implement-async-friendly-GetConnectedDevice.patch

From eeaecf615bda4192c31d3cb569f951bede052caa Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@agner.ch>
Date: Wed, 27 Mar 2024 22:13:19 +0100
Subject: [PATCH] [Python] Implement async friendly GetConnectedDevice

Currently GetConnectedDeviceSync() is blocking e.g. when a new session
needs to be created. This is not asyncio friendly as it blocks the
whole event loop.

Implement a asyncio friendly variant GetConnectedDevice() which is
a co-routine function which can be awaited.
---
 src/controller/python/chip/ChipDeviceCtrl.py | 58 ++++++++++++++++++--
 1 file changed, 54 insertions(+), 4 deletions(-)

diff --git a/src/controller/python/chip/ChipDeviceCtrl.py b/src/controller/python/chip/ChipDeviceCtrl.py
index 4a1b3af3e2..08dbdff224 100644
--- a/src/controller/python/chip/ChipDeviceCtrl.py
+++ b/src/controller/python/chip/ChipDeviceCtrl.py
@@ -780,6 +780,56 @@ class ChipDeviceControllerBase():
 
         return DeviceProxyWrapper(returnDevice, self._dmLib)
 
+    async def GetConnectedDevice(self, nodeid, allowPASE=True, timeoutMs: int = None):
+        ''' Returns DeviceProxyWrapper upon success.'''
+        self.CheckIsActive()
+
+        if allowPASE:
+            returnDevice = c_void_p(None)
+            res = self._ChipStack.Call(lambda: self._dmLib.pychip_GetDeviceBeingCommissioned(
+                self.devCtrl, nodeid, byref(returnDevice)), timeoutMs)
+            if res.is_success:
+                logging.info('Using PASE connection')
+                return DeviceProxyWrapper(returnDevice)
+
+        eventLoop = asyncio.get_running_loop()
+        future = eventLoop.create_future()
+
+        class DeviceAvailableClosure():
+            def __init__(self, loop, future: asyncio.Future):
+                self._returnDevice = c_void_p(None)
+                self._returnErr = None
+                self._event_loop = loop
+                self._future = future
+
+            def _deviceAvailable(self):
+                if self._returnDevice.value is not None:
+                    self._future.set_result(self._returnDevice)
+                else:
+                    self._future.set_exception(self._returnErr.to_exception())
+
+            def deviceAvailable(self, device, err):
+                self._returnDevice = c_void_p(device)
+                self._returnErr = err
+                self._event_loop.call_soon_threadsafe(self._deviceAvailable)
+                ctypes.pythonapi.Py_DecRef(ctypes.py_object(self))
+
+        closure = DeviceAvailableClosure(eventLoop, future)
+        ctypes.pythonapi.Py_IncRef(ctypes.py_object(closure))
+        self._ChipStack.Call(lambda: self._dmLib.pychip_GetConnectedDeviceByNodeId(
+            self.devCtrl, nodeid, ctypes.py_object(closure), _DeviceAvailableCallback),
+            timeoutMs).raise_on_error()
+
+        # The callback might have been received synchronously (during self._ChipStack.Call()).
+        # In that case the Future has already been set it will return immediately
+        if (timeoutMs):
+            timeout = float(timeoutMs) / 1000
+            await asyncio.wait_for(future, timeout=timeout)
+        else:
+            await future
+
+        return DeviceProxyWrapper(future.result(), self._dmLib)
+
     def ComputeRoundTripTimeout(self, nodeid, upperLayerProcessingTimeoutMs: int = 0):
         ''' Returns a computed timeout value based on the round-trip time it takes for the peer at the other end of the session to
             receive a message, process it and send it back. This is computed based on the session type, the type of transport,
@@ -804,7 +854,7 @@ class ChipDeviceControllerBase():
         eventLoop = asyncio.get_running_loop()
         future = eventLoop.create_future()
 
-        device = self.GetConnectedDeviceSync(nodeid, timeoutMs=None)
+        device = await self.GetConnectedDevice(nodeid, timeoutMs=None)
         ClusterCommand.TestOnlySendCommandTimedRequestFlagWithNoTimedInvoke(
             future, eventLoop, responseType, device.deviceProxy, ClusterCommand.CommandPath(
                 EndpointId=endpoint,
@@ -831,7 +881,7 @@ class ChipDeviceControllerBase():
         eventLoop = asyncio.get_running_loop()
         future = eventLoop.create_future()
 
-        device = self.GetConnectedDeviceSync(nodeid, timeoutMs=interactionTimeoutMs)
+        device = await self.GetConnectedDevice(nodeid, timeoutMs=interactionTimeoutMs)
         ClusterCommand.SendCommand(
             future, eventLoop, responseType, device.deviceProxy, ClusterCommand.CommandPath(
                 EndpointId=endpoint,
@@ -876,7 +926,7 @@ class ChipDeviceControllerBase():
         eventLoop = asyncio.get_running_loop()
         future = eventLoop.create_future()
 
-        device = self.GetConnectedDeviceSync(nodeid, timeoutMs=interactionTimeoutMs)
+        device = await self.GetConnectedDevice(nodeid, timeoutMs=interactionTimeoutMs)
 
         attrs = []
         for v in attributes:
@@ -1097,7 +1147,7 @@ class ChipDeviceControllerBase():
         eventLoop = asyncio.get_running_loop()
         future = eventLoop.create_future()
 
-        device = self.GetConnectedDeviceSync(nodeid)
+        device = await self.GetConnectedDevice(nodeid)
         attributePaths = [self._parseAttributePathTuple(
             v) for v in attributes] if attributes else None
         clusterDataVersionFilters = [self._parseDataVersionFilterTuple(
-- 
2.44.0