Fix DNS resolution inconsistency between logs and OTA operations

esphome/resolver.py

@@ -0,0 +1,61 @@
+"""DNS resolver for ESPHome using aioesphomeapi."""
+
+from __future__ import annotations
+
+import asyncio
+import threading
+
+from aioesphomeapi.core import ResolveAPIError, ResolveTimeoutAPIError
+import aioesphomeapi.host_resolver as hr
+
+from esphome.core import EsphomeError
+
+RESOLVE_TIMEOUT = 10.0  # seconds
+
+
+class AsyncResolver:
+    """Resolver using aioesphomeapi that runs in a thread for faster results.
+
+    This resolver uses aioesphomeapi's async_resolve_host to handle DNS resolution,
+    including proper .local domain fallback. Running in a thread allows us to get
+    the result immediately without waiting for asyncio.run() to complete its
+    cleanup cycle, which can take significant time.
+    """
+
+    def __init__(self) -> None:
+        """Initialize the resolver."""
+        self.result: list[hr.AddrInfo] | None = None
+        self.exception: Exception | None = None
+        self.event = threading.Event()
+
+    async def _resolve(self, hosts: list[str], port: int) -> None:
+        """Resolve hostnames to IP addresses."""
+        try:
+            self.result = await hr.async_resolve_host(
+                hosts, port, timeout=RESOLVE_TIMEOUT
+            )
+        except Exception as e:
+            self.exception = e
+        finally:
+            self.event.set()
+
+    def run(self, hosts: list[str], port: int) -> list[hr.AddrInfo]:
+        """Run the DNS resolution in a separate thread."""
+        thread = threading.Thread(
+            target=lambda: asyncio.run(self._resolve(hosts, port)), daemon=True
+        )
+        thread.start()
+
+        if not self.event.wait(
+            timeout=RESOLVE_TIMEOUT + 1.0
+        ):  # Give it 1 second more than the resolver timeout
+            raise EsphomeError("Timeout resolving IP address")
+
+        if exc := self.exception:
+            if isinstance(exc, ResolveAPIError):
+                raise EsphomeError(f"Error resolving IP address: {exc}") from exc
+            if isinstance(exc, ResolveTimeoutAPIError):
+                raise EsphomeError(f"Timeout resolving IP address: {exc}") from exc
+            raise exc
+
+        return self.result