Fix checking IP version when using IPv6.

This commit fixes an issue with ceilometer incorrectly determining the
IP version to use.  Previously, it checked whether the hostname was a
valid IPv6 address, but it should be resolving first to check whether
that is a valid IP address instead.

tests: Created test case that enables creating a UDPPublisher with
hostname for ipv4 and ipv6.

Closes-bug: #1616496

Change-Id: I586104fe69a03e64a0fb7572442b3175f880d80d
Co-authored-by: Joseph Richard <Joseph.Richard@windriver.com>

ceilometer/publisher/udp.py

@@ -23,7 +23,7 @@ from oslo_log import log
 from oslo_utils import netutils
 
 import ceilometer
-from ceilometer.i18n import _
+from ceilometer.i18n import _, _LW
 from ceilometer import publisher
 from ceilometer.publisher import utils
 
@@ -38,9 +38,22 @@ class UDPPublisher(publisher.PublisherBase):
         self.host, self.port = netutils.parse_host_port(
             parsed_url.netloc,
             default_port=cfg.CONF.collector.udp_port)
-        if netutils.is_valid_ipv6(self.host):
-            addr_family = socket.AF_INET6
+        addrinfo = None
+        try:
+            addrinfo = socket.getaddrinfo(self.host, None, socket.AF_INET6,
+                                          socket.SOCK_DGRAM)[0]
+        except socket.gaierror:
+            try:
+                addrinfo = socket.getaddrinfo(self.host, None, socket.AF_INET,
+                                              socket.SOCK_DGRAM)[0]
+            except socket.gaierror:
+                pass
+        if addrinfo:
+            addr_family = addrinfo[0]
         else:
+            LOG.warning(_LW(
+                        "Cannot resolve host %s, creating AF_INET socket..."),
+                        self.host)
             addr_family = socket.AF_INET
         self.socket = socket.socket(addr_family,
                                     socket.SOCK_DGRAM)

ceilometer/tests/unit/publisher/test_udp.py

@@ -127,6 +127,28 @@ class TestUDPPublisher(base.BaseTestCase):
         self._check_udp_socket('udp://[::1]:4952',
                                socket.AF_INET6)
 
+    def test_publisher_udp_socket_ipv4_hostname(self):
+        host = "ipv4.google.com"
+        try:
+            socket.getaddrinfo(host, None,
+                               socket.AF_INET,
+                               socket.SOCK_DGRAM)
+        except socket.gaierror:
+            self.skipTest("cannot resolve not running test")
+        url = "udp://"+host+":4952"
+        self._check_udp_socket(url, socket.AF_INET)
+
+    def test_publisher_udp_socket_ipv6_hostname(self):
+        host = "ipv6.google.com"
+        try:
+            socket.getaddrinfo(host, None,
+                               socket.AF_INET6,
+                               socket.SOCK_DGRAM)
+        except socket.gaierror:
+            self.skipTest("cannot resolve not running test")
+        url = "udp://"+host+":4952"
+        self._check_udp_socket(url, socket.AF_INET6)
+
     def test_published(self):
         self.data_sent = []
         with mock.patch('socket.socket',