Implement MTU discovery

Author: migibert

pynetlib/device.py

@@ -12,6 +12,7 @@ def __init__(self, id, name, flags=[], namespace=None):
         self.state = None
         self.inet = []
         self.inet6 = []
+        self.mtu = None
 
     def is_loopback(self):
         return 'LOOPBACK' in self.flags
@@ -54,32 +55,30 @@ def disable(self):
             self.refresh()
 
     def refresh(self):
-        output = execute_command('ip addr show %s' % self.name, namespace=self.namespace)
-        device_infos = get_devices_info(output)
-        if len(device_infos) != 1:
-            raise Exception('Only one device can be named %s inside the same namespace' % self.name)
-        id, name, flags, state, inet, inet6 = device_infos[0]
-        self.id = id
-        self.name = name
-        self.flags = flags
-        self.state = state
-        self.inet = inet
-        self.inet6 = inet6
+        devices = Device.discover(namespace=self.namespace)
+        if self not in devices:
+            raise ObjectNotFoundException(self)
+        found = devices[devices.index(self)]
+        self.flags = found.flags
+        self.inet = found.inet
+        self.inet6 = found.inet6
+        self.mtu = found.mtu
 
     @staticmethod
     def discover(namespace=None):
         devices = []
         output = execute_command('ip addr list', namespace=namespace)
-        for id, name, flags, state, inet, inet6 in get_devices_info(output):
+        for id, name, flags, state, inet, inet6, mtu in get_devices_info(output):
             device = Device(id, name, flags=flags, namespace=namespace)
             device.state = state
             device.inet = inet
             device.inet6 = inet6
+            device.mtu = mtu
             devices.append(device)
         return devices
 
     def __eq__(self, other):
         return self.name == other.name and self.id == other.id
 
     def __repr__(self):
-        return '<' + ','.join([self.id, self.name, str(self.inet), str(self.inet6)]) + '>'
+        return '<' + ','.join([self.id, self.name, str(self.inet), str(self.inet6), str(self.mtu)]) + '>'

pynetlib/tests/fixtures/ip_addr_show

@@ -13,7 +13,6 @@ class TestDevice(unittest.TestCase):
 
     def setUp(self):
         self.ip_addr_list_output = read_file('ip_addr_list')
-        self.ip_addr_show_output = read_file('ip_addr_show')
 
     def test_init_device(self):
         id = '1'
@@ -25,6 +24,7 @@ def test_init_device(self):
         self.assertEqual(dev.inet, [])
         self.assertEqual(dev.inet6, [])
         self.assertIsNone(dev.state)
+        self.assertIsNone(dev.mtu)
 
     def test_init_loopback(self):
         id = '1'
@@ -206,17 +206,25 @@ def test_disable_down_device(self, execute_command):
 
     @mock.patch('pynetlib.device.execute_command')
     def test_refresh_device(self, execute_command):
-        execute_command.return_value = self.ip_addr_show_output
-        device = Device('1', 'eth0', flags=[])
+        execute_command.return_value = self.ip_addr_list_output
+        device = Device('2', 'eth0', flags=[])
         device.refresh()
-        execute_command.assert_called_once_with("ip addr show eth0", namespace=None)
+        execute_command.assert_called_once_with("ip addr list", namespace=None)
         self.assertEqual(device.id, '2')
         self.assertEqual(device.name, "eth0")
         self.assertEqual(device.flags, ['BROADCAST', 'MULTICAST', 'UP', 'LOWER_UP'])
-        self.assertEqual(device.inet, ['10.0.2.15/24'])
+        self.assertEqual(device.inet, ['10.0.2.15/24', '10.0.2.16/24'])
         self.assertEqual(device.inet6, ['fe80::a00:27ff:feea:67cf/64'])
+        self.assertEqual(device.mtu, '1500')
         self.assertIsNone(device.namespace)
 
+    @mock.patch('pynetlib.device.execute_command')
+    def test_refresh_non_existing_device(self, execute_command):
+        execute_command.return_value = self.ip_addr_list_output
+        device = Device('id', 'device', flags=[])
+        with self.assertRaises(ObjectNotFoundException):
+            device.refresh()
+            execute_command.assert_called_once_with("ip addr list", namespace=None)
 
 if __name__ == '__main__':
     unittest.main()

pynetlib/tests/test_device.py

@@ -3,7 +3,7 @@
 import unittest
 from pynetlib.utils import execute_command, find_values_or_default_value
 from pynetlib.namespace import Namespace
-from pynetlib.exceptions import ValueNotFoundException
+from nose_parameterized import parameterized
 
 
 class TestUtils(unittest.TestCase):
@@ -36,22 +36,16 @@ def test_find_values(self):
         value = find_values_or_default_value(values, 'key', single=True)
         self.assertEqual(value, 'value')
 
-    def test_find_values_non_existing_key(self):
-        values = 'key value'
-        value = find_values_or_default_value(values, 'test', single=True)
-        self.assertIsNone(value)
-
-    def test_find_values_non_existing_value(self):
-        values = 'key'
-        value = find_values_or_default_value(values, 'key', single=True)
-        self.assertIsNone(value)
-
-    def test_find_values_two_values(self):
-        values = 'key value key other'
-        values = find_values_or_default_value(values, 'key')
-        self.assertEqual(len(values), 2)
-        self.assertTrue('value' in values)
-        self.assertTrue('other' in values)
+    @parameterized.expand([
+        ('key value', 'key', True, None, 'value'),
+        ('', 'test', True, 'value', 'value'),
+        ('key', 'key', True, None, None),
+        ('key', 'key', True, 'test', 'test'),
+        ('key value1 key value2', 'key', False, None, ['value1', 'value2'])
+    ])
+    def test_find_values_or_default_value(self, values, key, single, default, expected):
+        value = find_values_or_default_value(values, key, single=single, default_value=default)
+        self.assertEqual(value, expected)
 
 
 if __name__ == '__main__':

pynetlib/tests/test_utils.py

@@ -23,7 +23,8 @@ def get_devices_info(output):
         state = find_values_or_default_value(block, 'state', single=True, default_value='UNKNOWN')
         inet = find_values_or_default_value(block, 'inet', default_value=[])
         inet6 = find_values_or_default_value(block, 'inet6', default_value=[])
-        devices.append((id, name, flags, state, inet, inet6))
+        mtu = find_values_or_default_value(block, 'mtu', default_value=None, single=True)
+        devices.append((id, name, flags, state, inet, inet6, mtu))
     return devices