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esphome/esphome/resolver.py
J. Nick Koston 830b9a881a redesign
2025-09-04 21:39:50 -05:00

68 lines
2.3 KiB
Python

"""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(threading.Thread):
"""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, hosts: list[str], port: int) -> None:
"""Initialize the resolver."""
super().__init__(daemon=True)
self.hosts = hosts
self.port = port
self.result: list[hr.AddrInfo] | None = None
self.exception: Exception | None = None
self.event = threading.Event()
async def _resolve(self) -> None:
"""Resolve hostnames to IP addresses."""
try:
self.result = await hr.async_resolve_host(
self.hosts, self.port, timeout=RESOLVE_TIMEOUT
)
except Exception as e: # pylint: disable=broad-except
# We need to catch all exceptions to ensure the event is set
# Otherwise the thread could hang forever
self.exception = e
finally:
self.event.set()
def run(self) -> None:
"""Run the DNS resolution."""
asyncio.run(self._resolve())
def resolve(self) -> list[hr.AddrInfo]:
"""Start the thread and wait for the result."""
self.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, ResolveTimeoutAPIError):
raise EsphomeError(f"Timeout resolving IP address: {exc}") from exc
if isinstance(exc, ResolveAPIError):
raise EsphomeError(f"Error resolving IP address: {exc}") from exc
raise exc
return self.result