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| Dir : //proc/self/root/opt/saltstack/salt/lib/python3.10/site-packages/tornado/platform/caresresolver.py |
import pycares # type: ignore
import socket
from tornado.concurrent import Future
from tornado import gen
from tornado.ioloop import IOLoop
from tornado.netutil import Resolver, is_valid_ip
import typing
if typing.TYPE_CHECKING:
from typing import Generator, Any, List, Tuple, Dict # noqa: F401
class CaresResolver(Resolver):
"""Name resolver based on the c-ares library.
This is a non-blocking and non-threaded resolver. It may not produce the
same results as the system resolver, but can be used for non-blocking
resolution when threads cannot be used.
``pycares`` will not return a mix of ``AF_INET`` and ``AF_INET6`` when
``family`` is ``AF_UNSPEC``, so it is only recommended for use in
``AF_INET`` (i.e. IPv4). This is the default for
``tornado.simple_httpclient``, but other libraries may default to
``AF_UNSPEC``.
.. versionchanged:: 5.0
The ``io_loop`` argument (deprecated since version 4.1) has been removed.
.. deprecated:: 6.2
This class is deprecated and will be removed in Tornado 7.0. Use the default
thread-based resolver instead.
"""
def initialize(self) -> None:
self.io_loop = IOLoop.current()
self.channel = pycares.Channel(sock_state_cb=self._sock_state_cb)
self.fds = {} # type: Dict[int, int]
def _sock_state_cb(self, fd: int, readable: bool, writable: bool) -> None:
state = (IOLoop.READ if readable else 0) | (IOLoop.WRITE if writable else 0)
if not state:
self.io_loop.remove_handler(fd)
del self.fds[fd]
elif fd in self.fds:
self.io_loop.update_handler(fd, state)
self.fds[fd] = state
else:
self.io_loop.add_handler(fd, self._handle_events, state)
self.fds[fd] = state
def _handle_events(self, fd: int, events: int) -> None:
read_fd = pycares.ARES_SOCKET_BAD
write_fd = pycares.ARES_SOCKET_BAD
if events & IOLoop.READ:
read_fd = fd
if events & IOLoop.WRITE:
write_fd = fd
self.channel.process_fd(read_fd, write_fd)
@gen.coroutine
def resolve(
self, host: str, port: int, family: int = 0
) -> "Generator[Any, Any, List[Tuple[int, Any]]]":
if is_valid_ip(host):
addresses = [host]
else:
# gethostbyname doesn't take callback as a kwarg
fut = Future() # type: Future[Tuple[Any, Any]]
self.channel.gethostbyname(
host, family, lambda result, error: fut.set_result((result, error))
)
result, error = yield fut
if error:
raise IOError(
"C-Ares returned error %s: %s while resolving %s"
% (error, pycares.errno.strerror(error), host)
)
addresses = result.addresses
addrinfo = []
for address in addresses:
if "." in address:
address_family = socket.AF_INET
elif ":" in address:
address_family = socket.AF_INET6
else:
address_family = socket.AF_UNSPEC
if family != socket.AF_UNSPEC and family != address_family:
raise IOError(
"Requested socket family %d but got %d" % (family, address_family)
)
addrinfo.append((typing.cast(int, address_family), (address, port)))
return addrinfo