bpo-30378: Fix the problem that SysLogHandler can't handle IPv6 addresses (#1676) (#1903)

Lib/logging/handlers.py

@@ -827,11 +827,26 @@ class SysLogHandler(logging.Handler):
             self.unixsocket = False
             if socktype is None:
                 socktype = socket.SOCK_DGRAM
-            self.socket = socket.socket(socket.AF_INET, socktype)
+            host, port = address
+            ress = socket.getaddrinfo(host, port, 0, socktype)
+            if not ress:
+                raise OSError("getaddrinfo returns an empty list")
+            for res in ress:
+                af, socktype, proto, _, sa = res
+                err = sock = None
+                try:
+                    sock = socket.socket(af, socktype, proto)
                     if socktype == socket.SOCK_STREAM:
-                self.socket.connect(address)
+                        sock.connect(sa)
+                    break
+                except OSError as exc:
+                    err = exc
+                    if sock is not None:
+                        sock.close()
+            if err is not None:
+                raise err
+            self.socket = sock
             self.socktype = socktype
-        self.formatter = None
 
     def _connect_unixsocket(self, address):
         use_socktype = self.socktype

Lib/test/test_logging.py

@@ -1663,7 +1663,7 @@ class SysLogHandlerTest(BaseTest):
         server.ready.wait()
         hcls = logging.handlers.SysLogHandler
         if isinstance(server.server_address, tuple):
-            self.sl_hdlr = hcls(('localhost', server.port))
+            self.sl_hdlr = hcls((server.server_address[0], server.port))
         else:
             self.sl_hdlr = hcls(server.server_address)
         self.log_output = ''
@@ -1723,6 +1723,24 @@ class UnixSysLogHandlerTest(SysLogHandlerTest):
         SysLogHandlerTest.tearDown(self)
         support.unlink(self.address)
 
+@unittest.skipUnless(support.IPV6_ENABLED,
+                     'IPv6 support required for this test.')
+@unittest.skipUnless(threading, 'Threading required for this test.')
+class IPv6SysLogHandlerTest(SysLogHandlerTest):
+
+    """Test for SysLogHandler with IPv6 host."""
+
+    server_class = TestUDPServer
+    address = ('::1', 0)
+
+    def setUp(self):
+        self.server_class.address_family = socket.AF_INET6
+        super(IPv6SysLogHandlerTest, self).setUp()
+
+    def tearDown(self):
+        self.server_class.address_family = socket.AF_INET
+        super(IPv6SysLogHandlerTest, self).tearDown()
+
 @unittest.skipUnless(threading, 'Threading required for this test.')
 class HTTPHandlerTest(BaseTest):
     """Test for HTTPHandler."""
@@ -4378,7 +4396,7 @@ def test_main():
         QueueHandlerTest, ShutdownTest, ModuleLevelMiscTest, BasicConfigTest,
         LoggerAdapterTest, LoggerTest, SMTPHandlerTest, FileHandlerTest,
         RotatingFileHandlerTest,  LastResortTest, LogRecordTest,
-        ExceptionTest, SysLogHandlerTest, HTTPHandlerTest,
+        ExceptionTest, SysLogHandlerTest, IPv6SysLogHandlerTest, HTTPHandlerTest,
         NTEventLogHandlerTest, TimedRotatingFileHandlerTest,
         UnixSocketHandlerTest, UnixDatagramHandlerTest, UnixSysLogHandlerTest,
         MiscTestCase

Misc/NEWS

@@ -45,6 +45,9 @@ Core and Builtins
 Library
 -------
 
+- bpo-30378: Fix the problem that logging.handlers.SysLogHandler cannot
+  handle IPv6 addresses.
+
 - bpo-29960: Preserve generator state when _random.Random.setstate()
   raises an exception.  Patch by Bryan Olson.