Switch to using the AsyncResolver with aiohttp (#114529)

* Bump aiodns to 3.2.0

changelog: https://github.com/saghul/aiodns/compare/v3.1.1...v3.2.0

* Switch to using the AsyncResolver with aiohttp

This avoids creating executor jobs to do DNS resolution

AsyncResolver was not usable before https://github.com/aio-libs/aiohttp/pull/8270
because it did not fallback to fallback to A records and only returned AAAA records
in most cases when IPv6 was available

This is a backport of https://github.com/aio-libs/aiohttp/pull/8270

* Switch to using the AsyncResolver with aiohttp

This avoids creating executor jobs to do DNS resolution

AsyncResolver was not usable before https://github.com/aio-libs/aiohttp/pull/8270
because it did not fallback to fallback to A records and only returned AAAA records
in most cases when IPv6 was available

This is a backport of https://github.com/aio-libs/aiohttp/pull/8270

* Switch to using the AsyncResolver with aiohttp

This avoids creating executor jobs to do DNS resolution

AsyncResolver was not usable before https://github.com/aio-libs/aiohttp/pull/8270
because it did not fallback to fallback to A records and only returned AAAA records
in most cases when IPv6 was available

This is a backport of https://github.com/aio-libs/aiohttp/pull/8270

* Switch to using the AsyncResolver with aiohttp

This avoids creating executor jobs to do DNS resolution

AsyncResolver was not usable before https://github.com/aio-libs/aiohttp/pull/8270
because it did not fallback to fallback to A records and only returned AAAA records
in most cases when IPv6 was available

This is a backport of https://github.com/aio-libs/aiohttp/pull/8270

* fixes

* fix mocking in next_dns

* fix unmocked calls in blink

* more mocking fixes

* more fixes

* more fixes

* Fix missing mocking in nextdns tests

extracted from #114539

* extract from context

.coveragerc

@@ -7,6 +7,7 @@ source = homeassistant
 omit =
     homeassistant/__main__.py
     homeassistant/helpers/signal.py
+    homeassistant/helpers/backports/*
     homeassistant/scripts/__init__.py
     homeassistant/scripts/check_config.py
     homeassistant/scripts/ensure_config.py

homeassistant/helpers/aiohttp_client.py

@@ -22,6 +22,7 @@ from homeassistant.loader import bind_hass
 from homeassistant.util import ssl as ssl_util
 from homeassistant.util.json import json_loads
 
+from .backports.aiohttp_resolver import AsyncResolver
 from .frame import warn_use
 from .json import json_dumps
 
@@ -310,6 +311,7 @@ def _async_get_connector(
         ssl=ssl_context,
         limit=MAXIMUM_CONNECTIONS,
         limit_per_host=MAXIMUM_CONNECTIONS_PER_HOST,
+        resolver=AsyncResolver(),
     )
     connectors[connector_key] = connector
 

homeassistant/helpers/backports/__init__.py

@@ -0,0 +1 @@
+"""Backports for helpers."""

homeassistant/helpers/backports/aiohttp_resolver.py

@@ -0,0 +1,116 @@
+"""Backport of aiohttp's AsyncResolver for Home Assistant.
+
+This is a backport of the AsyncResolver class from aiohttp 3.10.
+
+Before aiohttp 3.10, on system with IPv6 support, AsyncResolver would not fallback
+to providing A records when AAAA records were not available.
+
+Additionally, unlike the ThreadedResolver, AsyncResolver
+did not handle link-local addresses correctly.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import socket
+import sys
+from typing import Any, TypedDict
+
+import aiodns
+from aiohttp.abc import AbstractResolver
+
+# This is a backport of https://github.com/aio-libs/aiohttp/pull/8270
+# This can be removed once aiohttp 3.10 is the minimum supported version.
+
+_NUMERIC_SOCKET_FLAGS = socket.AI_NUMERICHOST | socket.AI_NUMERICSERV
+_SUPPORTS_SCOPE_ID = sys.version_info >= (3, 9, 0)
+
+
+class ResolveResult(TypedDict):
+    """Resolve result.
+
+    This is the result returned from an AbstractResolver's
+    resolve method.
+
+    :param hostname: The hostname that was provided.
+    :param host: The IP address that was resolved.
+    :param port: The port that was resolved.
+    :param family: The address family that was resolved.
+    :param proto: The protocol that was resolved.
+    :param flags: The flags that were resolved.
+    """
+
+    hostname: str
+    host: str
+    port: int
+    family: int
+    proto: int
+    flags: int
+
+
+class AsyncResolver(AbstractResolver):
+    """Use the `aiodns` package to make asynchronous DNS lookups."""
+
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        """Initialize the resolver."""
+        if aiodns is None:
+            raise RuntimeError("Resolver requires aiodns library")
+
+        self._loop = asyncio.get_running_loop()
+        self._resolver = aiodns.DNSResolver(*args, loop=self._loop, **kwargs)  # type: ignore[misc]
+
+    async def resolve(  # type: ignore[override]
+        self, host: str, port: int = 0, family: int = socket.AF_INET
+    ) -> list[ResolveResult]:
+        """Resolve a host name to an IP address."""
+        try:
+            resp = await self._resolver.getaddrinfo(
+                host,
+                port=port,
+                type=socket.SOCK_STREAM,
+                family=family,  # type: ignore[arg-type]
+                flags=socket.AI_ADDRCONFIG,
+            )
+        except aiodns.error.DNSError as exc:
+            msg = exc.args[1] if len(exc.args) >= 1 else "DNS lookup failed"
+            raise OSError(msg) from exc
+        hosts: list[ResolveResult] = []
+        for node in resp.nodes:
+            address: tuple[bytes, int] | tuple[bytes, int, int, int] = node.addr
+            family = node.family
+            if family == socket.AF_INET6:
+                if len(address) > 3 and address[3] and _SUPPORTS_SCOPE_ID:
+                    # This is essential for link-local IPv6 addresses.
+                    # LL IPv6 is a VERY rare case. Strictly speaking, we should use
+                    # getnameinfo() unconditionally, but performance makes sense.
+                    result = await self._resolver.getnameinfo(
+                        (address[0].decode("ascii"), *address[1:]),
+                        _NUMERIC_SOCKET_FLAGS,
+                    )
+                    resolved_host = result.node
+                else:
+                    resolved_host = address[0].decode("ascii")
+                    port = address[1]
+            else:  # IPv4
+                assert family == socket.AF_INET
+                resolved_host = address[0].decode("ascii")
+                port = address[1]
+            hosts.append(
+                ResolveResult(
+                    hostname=host,
+                    host=resolved_host,
+                    port=port,
+                    family=family,
+                    proto=0,
+                    flags=_NUMERIC_SOCKET_FLAGS,
+                )
+            )
+
+        if not hosts:
+            raise OSError("DNS lookup failed")
+
+        return hosts
+
+    async def close(self) -> None:
+        """Close the resolver."""
+        self._resolver.cancel()

homeassistant/package_constraints.txt

@@ -2,6 +2,7 @@
 
 aiodhcpwatcher==1.0.0
 aiodiscover==2.0.0
+aiodns==3.2.0
 aiohttp-fast-url-dispatcher==0.3.0
 aiohttp-zlib-ng==0.3.1
 aiohttp==3.9.3

pyproject.toml

@@ -23,6 +23,7 @@ classifiers = [
 ]
 requires-python = ">=3.12.0"
 dependencies    = [
+    "aiodns==3.2.0",
     "aiohttp==3.9.3",
     "aiohttp_cors==0.7.0",
     "aiohttp-fast-url-dispatcher==0.3.0",

requirements.txt

@@ -3,6 +3,7 @@
 -c homeassistant/package_constraints.txt
 
 # Home Assistant Core
+aiodns==3.2.0
 aiohttp==3.9.3
 aiohttp_cors==0.7.0
 aiohttp-fast-url-dispatcher==0.3.0