Add new network activators to bring up interfaces (#919)

Currently _bring_up_interfaces() is a no-op for any distro using
renderers. We need to be able to support bringing up a single
interfaces, a list of interfaces, and all interfaces. This should be
independent of the renderers, as the network config is often
generated independent of the mechanism used to apply it.

Additionally, I included a refactor to remove
"_supported_write_network_config". We had a confusing call chain of
apply_network_config->_write_network_config->_supported_write_network_config.
The last two have been combined.

2 files changed, 178 insertions, 1 deletions

diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
index 1aab51ee..43e209c1 100644
--- a/tests/unittests/test_net.py
+++ b/tests/unittests/test_net.py
@@ -5277,7 +5277,7 @@ class TestNetRenderers(CiTestCase):
         # available should only be called until one is found.
         m_eni_avail.return_value = True
         m_sysc_avail.side_effect = Exception("Should not call me")
-        found = renderers.search(priority=['eni', 'sysconfig'], first=True)
+        found = renderers.search(priority=['eni', 'sysconfig'], first=True)[0]
         self.assertEqual(['eni'], [found[0]])
 
     @mock.patch("cloudinit.net.renderers.sysconfig.available")
diff --git a/tests/unittests/test_net_activators.py b/tests/unittests/test_net_activators.py
new file mode 100644
index 00000000..f11486ff
--- /dev/null
+++ b/tests/unittests/test_net_activators.py
@@ -0,0 +1,177 @@
+from collections import namedtuple
+from unittest.mock import patch
+
+import pytest
+
+from cloudinit.net.activators import (
+    DEFAULT_PRIORITY,
+    search_activator,
+    select_activator,
+)
+from cloudinit.net.activators import (
+    IfUpDownActivator,
+    NetplanActivator,
+    NetworkManagerActivator
+)
+from cloudinit.net.network_state import parse_net_config_data
+from cloudinit.safeyaml import load
+
+
+V1_CONFIG = """\
+version: 1
+config:
+- type: physical
+  name: eth0
+- type: physical
+  name: eth1
+"""
+
+V2_CONFIG = """\
+version: 2
+ethernets:
+  eth0:
+    dhcp4: true
+  eth1:
+    dhcp4: true
+"""
+
+IF_UP_DOWN_AVAILABLE_CALLS = [
+    (('ifquery',), {'search': ['/sbin', '/usr/sbin'], 'target': None}),
+    (('ifup',), {'search': ['/sbin', '/usr/sbin'], 'target': None}),
+    (('ifdown',), {'search': ['/sbin', '/usr/sbin'], 'target': None}),
+]
+
+IF_UP_DOWN_CALL_LIST = [
+    ((['ifup', 'eth0'], ), {}),
+    ((['ifup', 'eth1'], ), {}),
+]
+
+NETPLAN_AVAILABLE_CALLS = [
+    (('netplan',), {'search': ['/usr/sbin', '/sbin'], 'target': None}),
+]
+
+NETPLAN_CALL_LIST = [
+    ((['netplan', 'apply'], ), {'capture': True}),
+]
+
+NETWORK_MANAGER_AVAILABLE_CALLS = [
+    (('nmcli',), {'target': None}),
+]
+
+NETWORK_MANAGER_CALL_LIST = [
+    ((['nmcli', 'connection', 'up', 'eth0'], ), {}),
+    ((['nmcli', 'connection', 'up', 'eth1'], ), {}),
+]
+
+
+@pytest.yield_fixture
+def available_mocks():
+    mocks = namedtuple('Mocks', 'm_which, m_file')
+    with patch('cloudinit.subp.which', return_value=True) as m_which:
+        with patch('os.path.isfile', return_value=True) as m_file:
+            yield mocks(m_which, m_file)
+
+
+@pytest.yield_fixture
+def unavailable_mocks():
+    mocks = namedtuple('Mocks', 'm_which, m_file')
+    with patch('cloudinit.subp.which', return_value=False) as m_which:
+        with patch('os.path.isfile', return_value=False) as m_file:
+            yield mocks(m_which, m_file)
+
+
+class TestSearchAndSelect:
+    def test_defaults(self, available_mocks):
+        resp = search_activator()
+        assert resp == DEFAULT_PRIORITY
+
+        activator = select_activator()
+        assert activator == DEFAULT_PRIORITY[0]
+
+    def test_priority(self, available_mocks):
+        new_order = [NetplanActivator, NetworkManagerActivator]
+        resp = search_activator(priority=new_order)
+        assert resp == new_order
+
+        activator = select_activator(priority=new_order)
+        assert activator == new_order[0]
+
+    def test_target(self, available_mocks):
+        search_activator(target='/tmp')
+        assert '/tmp' == available_mocks.m_which.call_args[1]['target']
+
+        select_activator(target='/tmp')
+        assert '/tmp' == available_mocks.m_which.call_args[1]['target']
+
+    @patch('cloudinit.net.activators.IfUpDownActivator.available',
+           return_value=False)
+    def test_first_not_available(self, m_available, available_mocks):
+        resp = search_activator()
+        assert resp == DEFAULT_PRIORITY[1:]
+
+        resp = select_activator()
+        assert resp == DEFAULT_PRIORITY[1]
+
+    def test_priority_not_exist(self, available_mocks):
+        with pytest.raises(ValueError):
+            search_activator(priority=['spam', 'eggs'])
+        with pytest.raises(ValueError):
+            select_activator(priority=['spam', 'eggs'])
+
+    def test_none_available(self, unavailable_mocks):
+        resp = search_activator()
+        assert resp == []
+
+        with pytest.raises(RuntimeError):
+            select_activator()
+
+
+@pytest.mark.parametrize('activator, available_calls, expected_call_list', [
+    (IfUpDownActivator, IF_UP_DOWN_AVAILABLE_CALLS, IF_UP_DOWN_CALL_LIST),
+    (NetplanActivator, NETPLAN_AVAILABLE_CALLS, NETPLAN_CALL_LIST),
+    (NetworkManagerActivator, NETWORK_MANAGER_AVAILABLE_CALLS,
+     NETWORK_MANAGER_CALL_LIST),
+])
+class TestIfUpDownActivator:
+    def test_available(
+        self, activator, available_calls, expected_call_list, available_mocks
+    ):
+        activator.available()
+        assert available_mocks.m_which.call_args_list == available_calls
+
+    @patch('cloudinit.subp.subp', return_value=('', ''))
+    def test_bring_up_interface(
+        self, m_subp, activator, available_calls, expected_call_list,
+        available_mocks
+    ):
+        activator.bring_up_interface('eth0')
+        assert len(m_subp.call_args_list) == 1
+        assert m_subp.call_args_list[0] == expected_call_list[0]
+
+    @patch('cloudinit.subp.subp', return_value=('', ''))
+    def test_bring_up_interfaces(
+        self, m_subp, activator, available_calls, expected_call_list,
+        available_mocks
+    ):
+        activator.bring_up_interfaces(['eth0', 'eth1'])
+        assert expected_call_list == m_subp.call_args_list
+
+    @patch('cloudinit.subp.subp', return_value=('', ''))
+    def test_bring_up_all_interfaces_v1(
+        self, m_subp, activator, available_calls, expected_call_list,
+        available_mocks
+    ):
+        network_state = parse_net_config_data(load(V1_CONFIG))
+        activator.bring_up_all_interfaces(network_state)
+        for call in m_subp.call_args_list:
+            assert call in expected_call_list
+
+    @patch('cloudinit.subp.subp', return_value=('', ''))
+    def test_bring_up_all_interfaces_v2(
+        self, m_subp, activator, available_calls, expected_call_list,
+        available_mocks
+    ):
+        network_state = parse_net_config_data(load(V2_CONFIG))
+        activator.bring_up_all_interfaces(network_state)
+        for call in m_subp.call_args_list:
+            assert call in expected_call_list