Speed-up wemo discovery (#46821)

* Speed-up wemo discovery

* Use gather_with_concurrency to limit concurrent executor usage

* Comment fixup: asyncio executors -> executor threads

homeassistant/components/wemo/__init__.py

@@ -1,5 +1,4 @@
 """Support for WeMo device discovery."""
-import asyncio
 import logging
 
 import pywemo
@@ -16,9 +15,14 @@ from homeassistant.core import HomeAssistant, callback
 from homeassistant.helpers import config_validation as cv
 from homeassistant.helpers.dispatcher import async_dispatcher_send
 from homeassistant.helpers.event import async_call_later
+from homeassistant.util.async_ import gather_with_concurrency
 
 from .const import DOMAIN
 
+# Max number of devices to initialize at once. This limit is in place to
+# avoid tying up too many executor threads with WeMo device setup.
+MAX_CONCURRENCY = 3
+
 # Mapping from Wemo model_name to domain.
 WEMO_MODEL_DISPATCH = {
     "Bridge": LIGHT_DOMAIN,
@@ -114,11 +118,12 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry):
     static_conf = config.get(CONF_STATIC, [])
     if static_conf:
         _LOGGER.debug("Adding statically configured WeMo devices...")
-        for device in await asyncio.gather(
+        for device in await gather_with_concurrency(
+            MAX_CONCURRENCY,
             *[
                 hass.async_add_executor_job(validate_static_config, host, port)
                 for host, port in static_conf
-            ]
+            ],
         ):
             if device:
                 wemo_dispatcher.async_add_unique_device(hass, device)
@@ -187,15 +192,44 @@ class WemoDiscovery:
         self._wemo_dispatcher = wemo_dispatcher
         self._stop = None
         self._scan_delay = 0
+        self._upnp_entries = set()
+
+    async def async_add_from_upnp_entry(self, entry: pywemo.ssdp.UPNPEntry) -> None:
+        """Create a WeMoDevice from an UPNPEntry and add it to the dispatcher.
+
+        Uses the self._upnp_entries set to avoid interrogating the same device
+        multiple times.
+        """
+        if entry in self._upnp_entries:
+            return
+        try:
+            device = await self._hass.async_add_executor_job(
+                pywemo.discovery.device_from_uuid_and_location,
+                entry.udn,
+                entry.location,
+            )
+        except pywemo.PyWeMoException as err:
+            _LOGGER.error("Unable to setup WeMo %r (%s)", entry, err)
+        else:
+            self._wemo_dispatcher.async_add_unique_device(self._hass, device)
+            self._upnp_entries.add(entry)
 
     async def async_discover_and_schedule(self, *_) -> None:
         """Periodically scan the network looking for WeMo devices."""
         _LOGGER.debug("Scanning network for WeMo devices...")
         try:
-            for device in await self._hass.async_add_executor_job(
+            # pywemo.ssdp.scan is a light-weight UDP UPnP scan for WeMo devices.
-                pywemo.discover_devices
+            entries = await self._hass.async_add_executor_job(pywemo.ssdp.scan)
-            ):
+
-                self._wemo_dispatcher.async_add_unique_device(self._hass, device)
+            # async_add_from_upnp_entry causes multiple HTTP requests to be sent
+            # to the WeMo device for the initial setup of the WeMoDevice
+            # instance. This may take some time to complete. The per-device
+            # setup work is done in parallel to speed up initial setup for the
+            # component.
+            await gather_with_concurrency(
+                MAX_CONCURRENCY,
+                *[self.async_add_from_upnp_entry(entry) for entry in entries],
+            )
         finally:
             # Run discovery more frequently after hass has just started.
             self._scan_delay = min(

tests/components/wemo/test_init.py

@@ -100,28 +100,41 @@ async def test_static_config_with_invalid_host(hass):
 async def test_discovery(hass, pywemo_registry):
     """Verify that discovery dispatches devices to the platform for setup."""
 
-    def create_device(counter):
+    def create_device(uuid, location):
         """Create a unique mock Motion detector device for each counter value."""
         device = create_autospec(pywemo.Motion, instance=True)
-        device.host = f"{MOCK_HOST}_{counter}"
+        device.host = location
-        device.port = MOCK_PORT + counter
+        device.port = MOCK_PORT
-        device.name = f"{MOCK_NAME}_{counter}"
+        device.name = f"{MOCK_NAME}_{uuid}"
-        device.serialnumber = f"{MOCK_SERIAL_NUMBER}_{counter}"
+        device.serialnumber = f"{MOCK_SERIAL_NUMBER}_{uuid}"
         device.model_name = "Motion"
         device.get_state.return_value = 0  # Default to Off
         return device
 
-    pywemo_devices = [create_device(0), create_device(1)]
+    def create_upnp_entry(counter):
+        return pywemo.ssdp.UPNPEntry.from_response(
+            "\r\n".join(
+                [
+                    "",
+                    f"LOCATION: http://192.168.1.100:{counter}/setup.xml",
+                    f"USN: uuid:Socket-1_0-SERIAL{counter}::upnp:rootdevice",
+                    "",
+                ]
+            )
+        )
+
+    upnp_entries = [create_upnp_entry(0), create_upnp_entry(1)]
     # Setup the component and start discovery.
     with patch(
-        "pywemo.discover_devices", return_value=pywemo_devices
+        "pywemo.discovery.device_from_uuid_and_location", side_effect=create_device
-    ) as mock_discovery:
+    ), patch("pywemo.ssdp.scan", return_value=upnp_entries) as mock_scan:
         assert await async_setup_component(
             hass, DOMAIN, {DOMAIN: {CONF_DISCOVERY: True}}
         )
         await pywemo_registry.semaphore.acquire()  # Returns after platform setup.
-        mock_discovery.assert_called()
+        mock_scan.assert_called()
-        pywemo_devices.append(create_device(2))
+        # Add two of the same entries to test deduplication.
+        upnp_entries.extend([create_upnp_entry(2), create_upnp_entry(2)])
 
         # Test that discovery runs periodically and the async_dispatcher_send code works.
         async_fire_time_changed(