Add netutils.get_my_ipv6()

Analog to netutils.get_my_ipv4(), except will return an
IPv6 address on the local host.

Change-Id: I26812ca6eaaeff70796bafa9f735d15d80f1bc30

oslo_utils/netutils.py

@@ -414,6 +414,52 @@ def _get_my_ipv4_address():
     return LOCALHOST
 
 
+def get_my_ipv6():
+    """Returns the actual IPv6 address of the local machine.
+
+    This code figures out what source address would be used if some traffic
+    were to be sent out to some well known address on the Internet. In this
+    case, IPv6 from RFC3849 is used, but the specific address does not
+    matter much. No traffic is actually sent.
+
+    .. versionadded:: 6.1
+       Return ``'::1'`` if there is no default interface.
+    """
+    try:
+        csock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
+        csock.connect(('2001:db8::1', 80))
+        (addr, _, _, _) = csock.getsockname()
+        csock.close()
+        return addr
+    except socket.error:
+        return _get_my_ipv6_address()
+
+
+def _get_my_ipv6_address():
+    """Figure out the best IPv6 address
+    """
+    LOCALHOST = '::1'
+    gtw = netifaces.gateways()
+    try:
+        interface = gtw['default'][netifaces.AF_INET6][1]
+    except (KeyError, IndexError):
+        LOG.info('Could not determine default network interface, '
+                 'using %s for IPv6 address', LOCALHOST)
+        return LOCALHOST
+
+    try:
+        return netifaces.ifaddresses(interface)[netifaces.AF_INET6][0]['addr']
+    except (KeyError, IndexError):
+        LOG.info('Could not determine IPv6 address for interface '
+                 '%(interface)s, using %(address)s',
+                 {'interface': interface, 'address': LOCALHOST})
+    except Exception as e:
+        LOG.info('Could not determine IPv6 address for '
+                 'interface %(interface)s: %(error)s',
+                 {'interface': interface, 'error': e})
+    return LOCALHOST
+
+
 class _ModifiedSplitResult(parse.SplitResult):
     """Split results class for urlsplit."""
 

oslo_utils/tests/test_netutils.py

@@ -276,13 +276,21 @@ class NetworkUtilsTest(test_base.BaseTestCase):
         for input_str in invalid_inputs:
             self.assertFalse(netutils.is_valid_port(input_str))
 
-    def test_get_my_ip(self):
+    def test_get_my_ipv4(self):
         sock_attrs = {
             'return_value.getsockname.return_value': ['1.2.3.4', '']}
         with mock.patch('socket.socket', **sock_attrs):
             addr = netutils.get_my_ipv4()
         self.assertEqual(addr, '1.2.3.4')
 
+    def test_get_my_ipv6(self):
+        sock_attrs = {
+            'return_value.getsockname.return_value': ['2001:db8::2', '',
+                                                      '', '']}
+        with mock.patch('socket.socket', **sock_attrs):
+            addr = netutils.get_my_ipv6()
+        self.assertEqual(addr, '2001:db8::2')
+
     def test_is_int_in_range(self):
         valid_inputs = [(1, -100, 100),
                         ('1', -100, 100),
@@ -323,37 +331,44 @@ class NetworkUtilsTest(test_base.BaseTestCase):
 
     @mock.patch('socket.socket')
     @mock.patch('oslo_utils.netutils._get_my_ipv4_address')
-    def test_get_my_ip_socket_error(self, ip, mock_socket):
+    def test_get_my_ipv4_socket_error(self, ip, mock_socket):
         mock_socket.side_effect = socket.error
         ip.return_value = '1.2.3.4'
         addr = netutils.get_my_ipv4()
         self.assertEqual(addr, '1.2.3.4')
 
-    @mock.patch('netifaces.gateways')
-    @mock.patch('netifaces.ifaddresses')
-    def test_get_my_ipv4_address_with_default_route(
-            self, ifaddr, gateways):
-        with mock.patch.dict(netifaces.__dict__, {'AF_INET': '0'}):
-            ifaddr.return_value = {'0': [{'addr': '172.18.204.1'}]}
-            addr = netutils._get_my_ipv4_address()
-        self.assertEqual('172.18.204.1', addr)
+    @mock.patch('socket.socket')
+    @mock.patch('oslo_utils.netutils._get_my_ipv6_address')
+    def test_get_my_ipv6_socket_error(self, ip, mock_socket):
+        mock_socket.side_effect = socket.error
+        ip.return_value = '2001:db8::2'
+        addr = netutils.get_my_ipv6()
+        self.assertEqual(addr, '2001:db8::2')
 
     @mock.patch('netifaces.gateways')
     @mock.patch('netifaces.ifaddresses')
-    def test_get_my_ipv4_address_without_default_route(
+    def test_get_my_ip_address_with_default_route(
             self, ifaddr, gateways):
-        with mock.patch.dict(netifaces.__dict__, {'AF_INET': '0'}):
-            ifaddr.return_value = {}
-            addr = netutils._get_my_ipv4_address()
-        self.assertEqual('127.0.0.1', addr)
+        ifaddr.return_value = {netifaces.AF_INET: [{'addr': '172.18.204.1'}],
+                               netifaces.AF_INET6: [{'addr': '2001:db8::2'}]}
+        self.assertEqual('172.18.204.1', netutils._get_my_ipv4_address())
+        self.assertEqual('2001:db8::2', netutils._get_my_ipv6_address())
+
+    @mock.patch('netifaces.gateways')
+    @mock.patch('netifaces.ifaddresses')
+    def test_get_my_ip_address_without_default_route(
+            self, ifaddr, gateways):
+        ifaddr.return_value = {}
+        self.assertEqual('127.0.0.1', netutils._get_my_ipv4_address())
+        self.assertEqual('::1', netutils._get_my_ipv6_address())
 
     @mock.patch('netifaces.gateways')
     @mock.patch('netifaces.ifaddresses')
     def test_get_my_ipv4_address_without_default_interface(
             self, ifaddr, gateways):
         gateways.return_value = {}
-        addr = netutils._get_my_ipv4_address()
-        self.assertEqual('127.0.0.1', addr)
+        self.assertEqual('127.0.0.1', netutils._get_my_ipv4_address())
+        self.assertEqual('::1', netutils._get_my_ipv6_address())
         self.assertFalse(ifaddr.called)
 
 

releasenotes/notes/netutils-get_my_ipv6-c9f124374655326b.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    New method ``netutils.get_my_ipv6()`` returns the IPv6 address
+    of the local machine.