ConfigDrive: fix writing of 'injected' files and legacy networking

Previous commit inadvertently disabled the consumption of 'injected' files
in configdrive (openstack server boot --file=/target/file=local-file)
unless the datasource was in 'pass' mode. The default mode is 'net' so
that was not likely to happen.

Also here are:
a.) some comments to apply_network_config

b.) add backwards compatibility for distros that do not yet implement
    apply_network_config by converting the network config into ENI format
    and calling apply_network.

    This is required because prior to the previous commit, those distros
    would have had 'apply_network' called with the openstack provided
    ENI file. But after this change they will have apply_network_config
    called by cloudinit's main.

c.) add network_state_to_eni for converting net config to eni
    it supports the not-actually-correct 'hwaddress' field in ENI

LP: #1602373

2 files changed, 91 insertions, 0 deletions

diff --git a/tests/unittests/test_distros/test_netconfig.py b/tests/unittests/test_distros/test_netconfig.py
index 9172e3aa..36eae2dc 100644
--- a/tests/unittests/test_distros/test_netconfig.py
+++ b/tests/unittests/test_distros/test_netconfig.py
@@ -319,3 +319,63 @@ defaultrouter="192.168.1.254"
 '''
             self.assertCfgEquals(expected_buf, str(write_buf))
             self.assertEqual(write_buf.mode, 0o644)
+
+    def test_apply_network_config_fallback(self):
+        fbsd_distro = self._get_distro('freebsd')
+
+        # a weak attempt to verify that we don't have an implementation
+        # of _write_network_config or apply_network_config in fbsd now,
+        # which would make this test not actually test the fallback.
+        self.assertRaises(
+            NotImplementedError, fbsd_distro._write_network_config,
+            BASE_NET_CFG)
+
+        # now run
+        mynetcfg = {
+            'config': [{"type": "physical", "name": "eth0",
+                        "mac_address": "c0:d6:9f:2c:e8:80",
+                        "subnets": [{"type": "dhcp"}]}],
+            'version': 1}
+
+        write_bufs = {}
+        read_bufs = {
+            '/etc/rc.conf': '',
+            '/etc/resolv.conf': '',
+        }
+
+        def replace_write(filename, content, mode=0o644, omode="wb"):
+            buf = WriteBuffer()
+            buf.mode = mode
+            buf.omode = omode
+            buf.write(content)
+            write_bufs[filename] = buf
+
+        def replace_read(fname, read_cb=None, quiet=False):
+            if fname not in read_bufs:
+                if fname in write_bufs:
+                    return str(write_bufs[fname])
+                raise IOError("%s not found" % fname)
+            else:
+                if fname in write_bufs:
+                    return str(write_bufs[fname])
+                return read_bufs[fname]
+
+        with ExitStack() as mocks:
+            mocks.enter_context(
+                mock.patch.object(util, 'subp', return_value=('vtnet0', '')))
+            mocks.enter_context(
+                mock.patch.object(os.path, 'exists', return_value=False))
+            mocks.enter_context(
+                mock.patch.object(util, 'write_file', replace_write))
+            mocks.enter_context(
+                mock.patch.object(util, 'load_file', replace_read))
+
+            fbsd_distro.apply_network_config(mynetcfg, bring_up=False)
+
+            self.assertIn('/etc/rc.conf', write_bufs)
+            write_buf = write_bufs['/etc/rc.conf']
+            expected_buf = '''
+ifconfig_vtnet0="DHCP"
+'''
+            self.assertCfgEquals(expected_buf, str(write_buf))
+            self.assertEqual(write_buf.mode, 0o644)
diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
index 3ae00fc6..6f4dad13 100644
--- a/tests/unittests/test_net.py
+++ b/tests/unittests/test_net.py
@@ -269,6 +269,37 @@ iface eth1000 inet dhcp
         self.assertEqual(expected.lstrip(), contents.lstrip())
 
 
+class TestEniNetworkStateToEni(TestCase):
+    mycfg = {
+        'config': [{"type": "physical", "name": "eth0",
+                    "mac_address": "c0:d6:9f:2c:e8:80",
+                    "subnets": [{"type": "dhcp"}]}],
+        'version': 1}
+    my_mac = 'c0:d6:9f:2c:e8:80'
+
+    def test_no_header(self):
+        rendered = eni.network_state_to_eni(
+            network_state=network_state.parse_net_config_data(self.mycfg),
+            render_hwaddress=True)
+        self.assertIn(self.my_mac, rendered)
+        self.assertIn("hwaddress", rendered)
+
+    def test_with_header(self):
+        header = "# hello world\n"
+        rendered = eni.network_state_to_eni(
+            network_state=network_state.parse_net_config_data(self.mycfg),
+            header=header, render_hwaddress=True)
+        self.assertIn(header, rendered)
+        self.assertIn(self.my_mac, rendered)
+
+    def test_no_hwaddress(self):
+        rendered = eni.network_state_to_eni(
+            network_state=network_state.parse_net_config_data(self.mycfg),
+            render_hwaddress=False)
+        self.assertNotIn(self.my_mac, rendered)
+        self.assertNotIn("hwaddress", rendered)
+
+
 class TestCmdlineConfigParsing(TestCase):
     simple_cfg = {
         'config': [{"type": "physical", "name": "eth0",