[Python-checkins] cpython (3.4): asyncio: Skip getaddrinfo if host is already resolved.

yury.selivanov python-checkins at python.org
Wed Dec 16 19:36:10 EST 2015


https://hg.python.org/cpython/rev/51df143c098d
changeset:   99583:51df143c098d
branch:      3.4
parent:      99567:7e7bdac6b259
user:        Yury Selivanov <yselivanov at sprymix.com>
date:        Wed Dec 16 19:31:17 2015 -0500
summary:
  asyncio: Skip getaddrinfo if host is already resolved.

getaddrinfo takes an exclusive lock on some platforms, causing clients to queue
up waiting for the lock if many names are being resolved concurrently. Users
may want to handle name resolution in their own code, for the sake of caching,
using an alternate resolver, or to measure DNS duration separately from
connection duration. Skip getaddrinfo if the "host" passed into
create_connection is already resolved.

See https://github.com/python/asyncio/pull/302 for details.

Patch by A. Jesse Jiryu Davis.

files:
  Lib/asyncio/base_events.py                    |  117 +++-
  Lib/asyncio/proactor_events.py                |    3 +-
  Lib/asyncio/selector_events.py                |    3 +-
  Lib/asyncio/test_utils.py                     |    9 +-
  Lib/test/test_asyncio/test_base_events.py     |  208 +++++++++-
  Lib/test/test_asyncio/test_events.py          |    4 -
  Lib/test/test_asyncio/test_proactor_events.py |    6 +-
  7 files changed, 283 insertions(+), 67 deletions(-)


diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py
--- a/Lib/asyncio/base_events.py
+++ b/Lib/asyncio/base_events.py
@@ -16,8 +16,10 @@
 
 import collections
 import concurrent.futures
+import functools
 import heapq
 import inspect
+import ipaddress
 import itertools
 import logging
 import os
@@ -70,49 +72,83 @@
         return repr(fd)
 
 
+# Linux's sock.type is a bitmask that can include extra info about socket.
+_SOCKET_TYPE_MASK = 0
+if hasattr(socket, 'SOCK_NONBLOCK'):
+    _SOCKET_TYPE_MASK |= socket.SOCK_NONBLOCK
+if hasattr(socket, 'SOCK_CLOEXEC'):
+    _SOCKET_TYPE_MASK |= socket.SOCK_CLOEXEC
+
+
+ at functools.lru_cache(maxsize=1024)
+def _ipaddr_info(host, port, family, type, proto):
+    # Try to skip getaddrinfo if "host" is already an IP. Since getaddrinfo
+    # blocks on an exclusive lock on some platforms, users might handle name
+    # resolution in their own code and pass in resolved IPs.
+    if proto not in {0, socket.IPPROTO_TCP, socket.IPPROTO_UDP} or host is None:
+        return None
+
+    type &= ~_SOCKET_TYPE_MASK
+    if type == socket.SOCK_STREAM:
+        proto = socket.IPPROTO_TCP
+    elif type == socket.SOCK_DGRAM:
+        proto = socket.IPPROTO_UDP
+    else:
+        return None
+
+    if hasattr(socket, 'inet_pton'):
+        if family == socket.AF_UNSPEC:
+            afs = [socket.AF_INET, socket.AF_INET6]
+        else:
+            afs = [family]
+
+        for af in afs:
+            # Linux's inet_pton doesn't accept an IPv6 zone index after host,
+            # like '::1%lo0', so strip it. If we happen to make an invalid
+            # address look valid, we fail later in sock.connect or sock.bind.
+            try:
+                if af == socket.AF_INET6:
+                    socket.inet_pton(af, host.partition('%')[0])
+                else:
+                    socket.inet_pton(af, host)
+                return af, type, proto, '', (host, port)
+            except OSError:
+                pass
+
+        # "host" is not an IP address.
+        return None
+
+    # No inet_pton. (On Windows it's only available since Python 3.4.)
+    # Even though getaddrinfo with AI_NUMERICHOST would be non-blocking, it
+    # still requires a lock on some platforms, and waiting for that lock could
+    # block the event loop. Use ipaddress instead, it's just text parsing.
+    try:
+        addr = ipaddress.IPv4Address(host)
+    except ValueError:
+        try:
+            addr = ipaddress.IPv6Address(host.partition('%')[0])
+        except ValueError:
+            return None
+
+    af = socket.AF_INET if addr.version == 4 else socket.AF_INET6
+    if family not in (socket.AF_UNSPEC, af):
+        # "host" is wrong IP version for "family".
+        return None
+
+    return af, type, proto, '', (host, port)
+
+
 def _check_resolved_address(sock, address):
     # Ensure that the address is already resolved to avoid the trap of hanging
     # the entire event loop when the address requires doing a DNS lookup.
-    #
-    # getaddrinfo() is slow (around 10 us per call): this function should only
-    # be called in debug mode
-    family = sock.family
 
-    if family == socket.AF_INET:
-        host, port = address
-    elif family == socket.AF_INET6:
-        host, port = address[:2]
-    else:
+    if hasattr(socket, 'AF_UNIX') and sock.family == socket.AF_UNIX:
         return
 
-    # On Windows, socket.inet_pton() is only available since Python 3.4
-    if hasattr(socket, 'inet_pton'):
-        # getaddrinfo() is slow and has known issue: prefer inet_pton()
-        # if available
-        try:
-            socket.inet_pton(family, host)
-        except OSError as exc:
-            raise ValueError("address must be resolved (IP address), "
-                             "got host %r: %s"
-                             % (host, exc))
-    else:
-        # Use getaddrinfo(flags=AI_NUMERICHOST) to ensure that the address is
-        # already resolved.
-        type_mask = 0
-        if hasattr(socket, 'SOCK_NONBLOCK'):
-            type_mask |= socket.SOCK_NONBLOCK
-        if hasattr(socket, 'SOCK_CLOEXEC'):
-            type_mask |= socket.SOCK_CLOEXEC
-        try:
-            socket.getaddrinfo(host, port,
-                               family=family,
-                               type=(sock.type & ~type_mask),
-                               proto=sock.proto,
-                               flags=socket.AI_NUMERICHOST)
-        except socket.gaierror as err:
-            raise ValueError("address must be resolved (IP address), "
-                             "got host %r: %s"
-                             % (host, err))
+    host, port = address[:2]
+    if _ipaddr_info(host, port, sock.family, sock.type, sock.proto) is None:
+        raise ValueError("address must be resolved (IP address),"
+                         " got host %r" % host)
 
 
 def _run_until_complete_cb(fut):
@@ -535,7 +571,12 @@
 
     def getaddrinfo(self, host, port, *,
                     family=0, type=0, proto=0, flags=0):
-        if self._debug:
+        info = _ipaddr_info(host, port, family, type, proto)
+        if info is not None:
+            fut = futures.Future(loop=self)
+            fut.set_result([info])
+            return fut
+        elif self._debug:
             return self.run_in_executor(None, self._getaddrinfo_debug,
                                         host, port, family, type, proto, flags)
         else:
diff --git a/Lib/asyncio/proactor_events.py b/Lib/asyncio/proactor_events.py
--- a/Lib/asyncio/proactor_events.py
+++ b/Lib/asyncio/proactor_events.py
@@ -441,8 +441,7 @@
 
     def sock_connect(self, sock, address):
         try:
-            if self._debug:
-                base_events._check_resolved_address(sock, address)
+            base_events._check_resolved_address(sock, address)
         except ValueError as err:
             fut = futures.Future(loop=self)
             fut.set_exception(err)
diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -397,8 +397,7 @@
             raise ValueError("the socket must be non-blocking")
         fut = futures.Future(loop=self)
         try:
-            if self._debug:
-                base_events._check_resolved_address(sock, address)
+            base_events._check_resolved_address(sock, address)
         except ValueError as err:
             fut.set_exception(err)
         else:
diff --git a/Lib/asyncio/test_utils.py b/Lib/asyncio/test_utils.py
--- a/Lib/asyncio/test_utils.py
+++ b/Lib/asyncio/test_utils.py
@@ -446,9 +446,14 @@
     finally:
         logger.setLevel(old_level)
 
-def mock_nonblocking_socket():
+
+def mock_nonblocking_socket(proto=socket.IPPROTO_TCP, type=socket.SOCK_STREAM,
+                            family=socket.AF_INET):
     """Create a mock of a non-blocking socket."""
-    sock = mock.Mock(socket.socket)
+    sock = mock.MagicMock(socket.socket)
+    sock.proto = proto
+    sock.type = type
+    sock.family = family
     sock.gettimeout.return_value = 0.0
     return sock
 
diff --git a/Lib/test/test_asyncio/test_base_events.py b/Lib/test/test_asyncio/test_base_events.py
--- a/Lib/test/test_asyncio/test_base_events.py
+++ b/Lib/test/test_asyncio/test_base_events.py
@@ -32,6 +32,120 @@
 PY34 = sys.version_info >= (3, 4)
 
 
+def mock_socket_module():
+    m_socket = mock.MagicMock(spec=socket)
+    for name in (
+        'AF_INET', 'AF_INET6', 'AF_UNSPEC', 'IPPROTO_TCP', 'IPPROTO_UDP',
+        'SOCK_STREAM', 'SOCK_DGRAM', 'SOL_SOCKET', 'SO_REUSEADDR', 'inet_pton'
+    ):
+        if hasattr(socket, name):
+            setattr(m_socket, name, getattr(socket, name))
+        else:
+            delattr(m_socket, name)
+
+    m_socket.socket = mock.MagicMock()
+    m_socket.socket.return_value = test_utils.mock_nonblocking_socket()
+
+    return m_socket
+
+
+def patch_socket(f):
+    return mock.patch('asyncio.base_events.socket',
+                      new_callable=mock_socket_module)(f)
+
+
+class BaseEventTests(test_utils.TestCase):
+
+    def setUp(self):
+        super().setUp()
+        base_events._ipaddr_info.cache_clear()
+
+    def tearDown(self):
+        base_events._ipaddr_info.cache_clear()
+        super().tearDown()
+
+    def test_ipaddr_info(self):
+        UNSPEC = socket.AF_UNSPEC
+        INET = socket.AF_INET
+        INET6 = socket.AF_INET6
+        STREAM = socket.SOCK_STREAM
+        DGRAM = socket.SOCK_DGRAM
+        TCP = socket.IPPROTO_TCP
+        UDP = socket.IPPROTO_UDP
+
+        self.assertEqual(
+            (INET, STREAM, TCP, '', ('1.2.3.4', 1)),
+            base_events._ipaddr_info('1.2.3.4', 1, INET, STREAM, TCP))
+
+        self.assertEqual(
+            (INET, STREAM, TCP, '', ('1.2.3.4', 1)),
+            base_events._ipaddr_info('1.2.3.4', 1, UNSPEC, STREAM, TCP))
+
+        self.assertEqual(
+            (INET, DGRAM, UDP, '', ('1.2.3.4', 1)),
+            base_events._ipaddr_info('1.2.3.4', 1, UNSPEC, DGRAM, UDP))
+
+        # Socket type STREAM implies TCP protocol.
+        self.assertEqual(
+            (INET, STREAM, TCP, '', ('1.2.3.4', 1)),
+            base_events._ipaddr_info('1.2.3.4', 1, UNSPEC, STREAM, 0))
+
+        # Socket type DGRAM implies UDP protocol.
+        self.assertEqual(
+            (INET, DGRAM, UDP, '', ('1.2.3.4', 1)),
+            base_events._ipaddr_info('1.2.3.4', 1, UNSPEC, DGRAM, 0))
+
+        # No socket type.
+        self.assertIsNone(
+            base_events._ipaddr_info('1.2.3.4', 1, UNSPEC, 0, 0))
+
+        # IPv4 address with family IPv6.
+        self.assertIsNone(
+            base_events._ipaddr_info('1.2.3.4', 1, INET6, STREAM, TCP))
+
+        self.assertEqual(
+            (INET6, STREAM, TCP, '', ('::3', 1)),
+            base_events._ipaddr_info('::3', 1, INET6, STREAM, TCP))
+
+        self.assertEqual(
+            (INET6, STREAM, TCP, '', ('::3', 1)),
+            base_events._ipaddr_info('::3', 1, UNSPEC, STREAM, TCP))
+
+        # IPv6 address with family IPv4.
+        self.assertIsNone(
+            base_events._ipaddr_info('::3', 1, INET, STREAM, TCP))
+
+        # IPv6 address with zone index.
+        self.assertEqual(
+            (INET6, STREAM, TCP, '', ('::3%lo0', 1)),
+            base_events._ipaddr_info('::3%lo0', 1, INET6, STREAM, TCP))
+
+    @patch_socket
+    def test_ipaddr_info_no_inet_pton(self, m_socket):
+        del m_socket.inet_pton
+        self.test_ipaddr_info()
+
+    def test_check_resolved_address(self):
+        sock = socket.socket(socket.AF_INET)
+        base_events._check_resolved_address(sock, ('1.2.3.4', 1))
+
+        sock = socket.socket(socket.AF_INET6)
+        base_events._check_resolved_address(sock, ('::3', 1))
+        base_events._check_resolved_address(sock, ('::3%lo0', 1))
+        self.assertRaises(ValueError,
+                          base_events._check_resolved_address, sock, ('foo', 1))
+
+    def test_check_resolved_sock_type(self):
+        # Ensure we ignore extra flags in sock.type.
+        if hasattr(socket, 'SOCK_NONBLOCK'):
+            sock = socket.socket(type=socket.SOCK_STREAM | socket.SOCK_NONBLOCK)
+            base_events._check_resolved_address(sock, ('1.2.3.4', 1))
+
+        if hasattr(socket, 'SOCK_CLOEXEC'):
+            sock = socket.socket(type=socket.SOCK_STREAM | socket.SOCK_CLOEXEC)
+            base_events._check_resolved_address(sock, ('1.2.3.4', 1))
+
+
 class BaseEventLoopTests(test_utils.TestCase):
 
     def setUp(self):
@@ -875,7 +989,12 @@
         self.loop = asyncio.new_event_loop()
         self.set_event_loop(self.loop)
 
-    @mock.patch('asyncio.base_events.socket')
+    def tearDown(self):
+        # Clear mocked constants like AF_INET from the cache.
+        base_events._ipaddr_info.cache_clear()
+        super().tearDown()
+
+    @patch_socket
     def test_create_connection_multiple_errors(self, m_socket):
 
         class MyProto(asyncio.Protocol):
@@ -908,7 +1027,7 @@
 
         self.assertEqual(str(cm.exception), 'Multiple exceptions: err1, err2')
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket
     def test_create_connection_timeout(self, m_socket):
         # Ensure that the socket is closed on timeout
         sock = mock.Mock()
@@ -986,7 +1105,7 @@
         with self.assertRaises(OSError):
             self.loop.run_until_complete(coro)
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket
     def test_create_connection_multiple_errors_local_addr(self, m_socket):
 
         def bind(addr):
@@ -1018,6 +1137,46 @@
         self.assertTrue(str(cm.exception).startswith('Multiple exceptions: '))
         self.assertTrue(m_socket.socket.return_value.close.called)
 
+    def _test_create_connection_ip_addr(self, m_socket, allow_inet_pton):
+        # Test the fallback code, even if this system has inet_pton.
+        if not allow_inet_pton:
+            del m_socket.inet_pton
+
+        def getaddrinfo(*args, **kw):
+            self.fail('should not have called getaddrinfo')
+
+        m_socket.getaddrinfo = getaddrinfo
+        sock = m_socket.socket.return_value
+
+        self.loop.add_reader = mock.Mock()
+        self.loop.add_reader._is_coroutine = False
+        self.loop.add_writer = mock.Mock()
+        self.loop.add_writer._is_coroutine = False
+
+        coro = self.loop.create_connection(MyProto, '1.2.3.4', 80)
+        self.loop.run_until_complete(coro)
+        sock.connect.assert_called_with(('1.2.3.4', 80))
+        m_socket.socket.assert_called_with(family=m_socket.AF_INET,
+                                           proto=m_socket.IPPROTO_TCP,
+                                           type=m_socket.SOCK_STREAM)
+
+        sock.family = socket.AF_INET6
+        coro = self.loop.create_connection(MyProto, '::2', 80)
+
+        self.loop.run_until_complete(coro)
+        sock.connect.assert_called_with(('::2', 80))
+        m_socket.socket.assert_called_with(family=m_socket.AF_INET6,
+                                           proto=m_socket.IPPROTO_TCP,
+                                           type=m_socket.SOCK_STREAM)
+
+    @patch_socket
+    def test_create_connection_ip_addr(self, m_socket):
+        self._test_create_connection_ip_addr(m_socket, True)
+
+    @patch_socket
+    def test_create_connection_no_inet_pton(self, m_socket):
+        self._test_create_connection_ip_addr(m_socket, False)
+
     def test_create_connection_no_local_addr(self):
         @asyncio.coroutine
         def getaddrinfo(host, *args, **kw):
@@ -1153,11 +1312,9 @@
         f = self.loop.create_server(MyProto, '0.0.0.0', 0)
         self.assertRaises(OSError, self.loop.run_until_complete, f)
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket
     def test_create_server_nosoreuseport(self, m_socket):
         m_socket.getaddrinfo = socket.getaddrinfo
-        m_socket.SOCK_STREAM = socket.SOCK_STREAM
-        m_socket.SOL_SOCKET = socket.SOL_SOCKET
         del m_socket.SO_REUSEPORT
         m_socket.socket.return_value = mock.Mock()
 
@@ -1166,7 +1323,7 @@
 
         self.assertRaises(ValueError, self.loop.run_until_complete, f)
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket
     def test_create_server_cant_bind(self, m_socket):
 
         class Err(OSError):
@@ -1182,7 +1339,7 @@
         self.assertRaises(OSError, self.loop.run_until_complete, fut)
         self.assertTrue(m_sock.close.called)
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket
     def test_create_datagram_endpoint_no_addrinfo(self, m_socket):
         m_socket.getaddrinfo.return_value = []
         m_socket.getaddrinfo._is_coroutine = False
@@ -1211,7 +1368,7 @@
         self.assertRaises(
             OSError, self.loop.run_until_complete, coro)
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket 
     def test_create_datagram_endpoint_socket_err(self, m_socket):
         m_socket.getaddrinfo = socket.getaddrinfo
         m_socket.socket.side_effect = OSError
@@ -1234,7 +1391,7 @@
         self.assertRaises(
             ValueError, self.loop.run_until_complete, coro)
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket
     def test_create_datagram_endpoint_setblk_err(self, m_socket):
         m_socket.socket.return_value.setblocking.side_effect = OSError
 
@@ -1250,12 +1407,11 @@
             asyncio.DatagramProtocol)
         self.assertRaises(ValueError, self.loop.run_until_complete, coro)
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket
     def test_create_datagram_endpoint_cant_bind(self, m_socket):
         class Err(OSError):
             pass
 
-        m_socket.AF_INET6 = socket.AF_INET6
         m_socket.getaddrinfo = socket.getaddrinfo
         m_sock = m_socket.socket.return_value = mock.Mock()
         m_sock.bind.side_effect = Err
@@ -1369,11 +1525,8 @@
         self.loop.run_until_complete(protocol.done)
         self.assertEqual('CLOSED', protocol.state)
 
-    @mock.patch('asyncio.base_events.socket')
+    @patch_socket
     def test_create_datagram_endpoint_nosoreuseport(self, m_socket):
-        m_socket.getaddrinfo = socket.getaddrinfo
-        m_socket.SOCK_DGRAM = socket.SOCK_DGRAM
-        m_socket.SOL_SOCKET = socket.SOL_SOCKET
         del m_socket.SO_REUSEPORT
         m_socket.socket.return_value = mock.Mock()
 
@@ -1385,6 +1538,29 @@
 
         self.assertRaises(ValueError, self.loop.run_until_complete, coro)
 
+    @patch_socket
+    def test_create_datagram_endpoint_ip_addr(self, m_socket):
+        def getaddrinfo(*args, **kw):
+            self.fail('should not have called getaddrinfo')
+
+        m_socket.getaddrinfo = getaddrinfo
+        m_socket.socket.return_value.bind = bind = mock.Mock()
+        self.loop.add_reader = mock.Mock()
+        self.loop.add_reader._is_coroutine = False
+
+        reuseport_supported = hasattr(socket, 'SO_REUSEPORT')
+        coro = self.loop.create_datagram_endpoint(
+            lambda: MyDatagramProto(loop=self.loop),
+            local_addr=('1.2.3.4', 0),
+            reuse_address=False,
+            reuse_port=reuseport_supported)
+
+        self.loop.run_until_complete(coro)
+        bind.assert_called_with(('1.2.3.4', 0))
+        m_socket.socket.assert_called_with(family=m_socket.AF_INET,
+                                           proto=m_socket.IPPROTO_UDP,
+                                           type=m_socket.SOCK_DGRAM)
+
     def test_accept_connection_retry(self):
         sock = mock.Mock()
         sock.accept.side_effect = BlockingIOError()
diff --git a/Lib/test/test_asyncio/test_events.py b/Lib/test/test_asyncio/test_events.py
--- a/Lib/test/test_asyncio/test_events.py
+++ b/Lib/test/test_asyncio/test_events.py
@@ -1573,10 +1573,6 @@
              'selector': self.loop._selector.__class__.__name__})
 
     def test_sock_connect_address(self):
-        # In debug mode, sock_connect() must ensure that the address is already
-        # resolved (call _check_resolved_address())
-        self.loop.set_debug(True)
-
         addresses = [(socket.AF_INET, ('www.python.org', 80))]
         if support.IPV6_ENABLED:
             addresses.extend((
diff --git a/Lib/test/test_asyncio/test_proactor_events.py b/Lib/test/test_asyncio/test_proactor_events.py
--- a/Lib/test/test_asyncio/test_proactor_events.py
+++ b/Lib/test/test_asyncio/test_proactor_events.py
@@ -436,7 +436,7 @@
 class BaseProactorEventLoopTests(test_utils.TestCase):
 
     def setUp(self):
-        self.sock = mock.Mock(socket.socket)
+        self.sock = test_utils.mock_nonblocking_socket()
         self.proactor = mock.Mock()
 
         self.ssock, self.csock = mock.Mock(), mock.Mock()
@@ -491,8 +491,8 @@
         self.proactor.send.assert_called_with(self.sock, b'data')
 
     def test_sock_connect(self):
-        self.loop.sock_connect(self.sock, 123)
-        self.proactor.connect.assert_called_with(self.sock, 123)
+        self.loop.sock_connect(self.sock, ('1.2.3.4', 123))
+        self.proactor.connect.assert_called_with(self.sock, ('1.2.3.4', 123))
 
     def test_sock_accept(self):
         self.loop.sock_accept(self.sock)

-- 
Repository URL: https://hg.python.org/cpython


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