mirror of
https://github.com/esphome/esphome.git
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59 lines
2.0 KiB
Python
59 lines
2.0 KiB
Python
from __future__ import annotations
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import asyncio
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from contextlib import suppress
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from ipaddress import ip_address
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from icmplib import NameLookupError, async_resolve
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RESOLVE_TIMEOUT = 3.0
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async def _async_resolve_wrapper(hostname: str) -> list[str] | Exception:
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"""Wrap the icmplib async_resolve function."""
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with suppress(ValueError):
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return [str(ip_address(hostname))]
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try:
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async with asyncio.timeout(RESOLVE_TIMEOUT):
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return await async_resolve(hostname)
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except (TimeoutError, NameLookupError, UnicodeError) as ex:
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return ex
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class DNSCache:
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"""DNS cache for the dashboard."""
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def __init__(self, ttl: int | None = 120) -> None:
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"""Initialize the DNSCache."""
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self._cache: dict[str, tuple[float, list[str] | Exception]] = {}
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self._ttl = ttl
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def get_cached_addresses(
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self, hostname: str, now_monotonic: float
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) -> list[str] | None:
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"""Get cached addresses without triggering resolution.
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Returns None if not in cache, list of addresses if found.
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"""
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# Normalize hostname for consistent lookups
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normalized = hostname.rstrip(".").lower()
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if expire_time_addresses := self._cache.get(normalized):
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expire_time, addresses = expire_time_addresses
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if expire_time > now_monotonic and not isinstance(addresses, Exception):
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return addresses
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return None
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async def async_resolve(
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self, hostname: str, now_monotonic: float
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) -> list[str] | Exception:
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"""Resolve a hostname to a list of IP address."""
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if expire_time_addresses := self._cache.get(hostname):
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expire_time, addresses = expire_time_addresses
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if expire_time > now_monotonic:
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return addresses
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expires = now_monotonic + self._ttl
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addresses = await _async_resolve_wrapper(hostname)
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self._cache[hostname] = (expires, addresses)
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return addresses
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