Fix discovery by alias for smart devices (#1260)

Fixes #1259

kasa/cli/discover.py

@@ -239,13 +239,48 @@ def _echo_discovery_info(discovery_info) -> None:
     _conditional_echo("Decrypted", pf(dr.decrypted_data) if dr.decrypted_data else None)
 
 
-async def find_host_from_alias(alias, target="255.255.255.255", timeout=1, attempts=3):
+async def find_dev_from_alias(
+    alias: str,
+    credentials: Credentials | None,
+    target: str = "255.255.255.255",
+    timeout: int = 5,
+    attempts: int = 3,
+) -> Device | None:
     """Discover a device identified by its alias."""
-    for _attempt in range(1, attempts):
-        found_devs = await Discover.discover(target=target, timeout=timeout)
-        for _ip, dev in found_devs.items():
-            if dev.alias.lower() == alias.lower():
-                host = dev.host
-                return host
+    found_event = asyncio.Event()
+    found_device = []
+    seen_hosts = set()
 
-    return None
+    async def on_discovered(dev: Device):
+        if dev.host in seen_hosts:
+            return
+        seen_hosts.add(dev.host)
+        try:
+            await dev.update()
+        except Exception as ex:
+            echo(f"Error querying device {dev.host}: {ex}")
+            return
+        finally:
+            await dev.protocol.close()
+        if not dev.alias:
+            echo(f"Skipping device {dev.host} with no alias")
+            return
+        if dev.alias.lower() == alias.lower():
+            found_device.append(dev)
+            found_event.set()
+
+    async def do_discover():
+        for _ in range(1, attempts):
+            await Discover.discover(
+                target=target,
+                timeout=timeout,
+                credentials=credentials,
+                on_discovered=on_discovered,
+            )
+            if found_event.is_set():
+                break
+        found_event.set()
+
+    asyncio.create_task(do_discover())
+    await found_event.wait()
+    return found_device[0] if found_device else None

kasa/cli/main.py

@@ -275,18 +275,6 @@ async def cli(
     if alias is not None and host is not None:
         raise click.BadOptionUsage("alias", "Use either --alias or --host, not both.")
 
-    if alias is not None and host is None:
-        echo(f"Alias is given, using discovery to find host {alias}")
-
-        from .discover import find_host_from_alias
-
-        host = await find_host_from_alias(alias=alias, target=target)
-        if host:
-            echo(f"Found hostname is {host}")
-        else:
-            echo(f"No device with name {alias} found")
-            return
-
     if bool(password) != bool(username):
         raise click.BadOptionUsage(
             "username", "Using authentication requires both --username and --password"
@@ -299,7 +287,7 @@ async def cli(
     else:
         credentials = None
 
-    if host is None:
+    if host is None and alias is None:
         if ctx.invoked_subcommand and ctx.invoked_subcommand != "discover":
             error("Only discover is available without --host or --alias")
 
@@ -309,6 +297,7 @@ async def cli(
         return await ctx.invoke(discover)
 
     device_updated = False
+
     if type is not None and type not in {"smart", "camera"}:
         from kasa.deviceconfig import DeviceConfig
 
@@ -347,6 +336,19 @@ async def cli(
         )
         dev = await Device.connect(config=config)
         device_updated = True
+    elif alias:
+        echo(f"Alias is given, using discovery to find host {alias}")
+
+        from .discover import find_dev_from_alias
+
+        dev = await find_dev_from_alias(
+            alias=alias, target=target, credentials=credentials
+        )
+        if not dev:
+            echo(f"No device with name {alias} found")
+            return
+        echo(f"Found hostname by alias: {dev.host}")
+        device_updated = True
     else:
         from .discover import discover