net/cmdline: split interfaces_by_mac and init network config determination

Previously "cmdline" network configuration could be either
user-specified network-config=... configuration data, or
initramfs-provided configuration data.  Before data sources could modify
the order in which network config sources were considered, this
conflation didn't matter (and, indeed, in the default data source
configuration it will continue to not matter).

However, it _is_ desirable for a data source to be able to specify that
its network configuration should be preferred over the
initramfs-provided network configuration but still allow explicit
network-config=... configuration passed to the kernel cmdline to
continue to override both of those sources.

(This also modifies the Oracle data source to use read_initramfs_config
directly, which is effectively what it was using
read_kernel_cmdline_config for previously.)

3 files changed, 15 insertions, 17 deletions

diff --git a/cloudinit/sources/DataSourceOracle.py b/cloudinit/sources/DataSourceOracle.py
index 70b9c58a..76cfa38c 100644
--- a/cloudinit/sources/DataSourceOracle.py
+++ b/cloudinit/sources/DataSourceOracle.py
@@ -48,7 +48,7 @@ class DataSourceOracle(sources.DataSource):
             return False
 
         # network may be configured if iscsi root.  If that is the case
-        # then read_kernel_cmdline_config will return non-None.
+        # then read_initramfs_config will return non-None.
         if _is_iscsi_root():
             data = self.crawl_metadata()
         else:
@@ -118,10 +118,8 @@ class DataSourceOracle(sources.DataSource):
         We nonetheless return cmdline provided config if present
         and fallback to generate fallback."""
         if self._network_config == sources.UNSET:
-            cmdline_cfg = cmdline.read_kernel_cmdline_config()
-            if cmdline_cfg:
-                self._network_config = cmdline_cfg
-            else:
+            self._network_config = cmdline.read_initramfs_config()
+            if not self._network_config:
                 self._network_config = self.distro.generate_fallback_config()
         return self._network_config
 
@@ -137,7 +135,7 @@ def _is_platform_viable():
 
 
 def _is_iscsi_root():
-    return bool(cmdline.read_kernel_cmdline_config())
+    return bool(cmdline.read_initramfs_config())
 
 
 def _load_index(content):
diff --git a/cloudinit/sources/__init__.py b/cloudinit/sources/__init__.py
index 9d249366..c2baccd5 100644
--- a/cloudinit/sources/__init__.py
+++ b/cloudinit/sources/__init__.py
@@ -69,7 +69,7 @@ CLOUD_ID_REGION_PREFIX_MAP = {
 # NetworkConfigSource represents the canonical list of network config sources
 # that cloud-init knows about.  (Python 2.7 lacks PEP 435, so use a singleton
 # namedtuple as an enum; see https://stackoverflow.com/a/6971002)
-_NETCFG_SOURCE_NAMES = ('cmdline', 'ds', 'system_cfg', 'fallback')
+_NETCFG_SOURCE_NAMES = ('cmdline', 'ds', 'system_cfg', 'fallback', 'initramfs')
 NetworkConfigSource = namedtuple('NetworkConfigSource',
                                  _NETCFG_SOURCE_NAMES)(*_NETCFG_SOURCE_NAMES)
 
@@ -166,6 +166,7 @@ class DataSource(object):
     # should always be a subset of the members of NetworkConfigSource with no
     # duplicate entries.
     network_config_sources = (NetworkConfigSource.cmdline,
+                              NetworkConfigSource.initramfs,
                               NetworkConfigSource.system_cfg,
                               NetworkConfigSource.ds)
 
diff --git a/cloudinit/sources/tests/test_oracle.py b/cloudinit/sources/tests/test_oracle.py
index 97d62947..282382c5 100644
--- a/cloudinit/sources/tests/test_oracle.py
+++ b/cloudinit/sources/tests/test_oracle.py
@@ -133,9 +133,9 @@ class TestDataSourceOracle(test_helpers.CiTestCase):
         self.assertEqual(self.my_md['uuid'], ds.get_instance_id())
         self.assertEqual(my_userdata, ds.userdata_raw)
 
-    @mock.patch(DS_PATH + ".cmdline.read_kernel_cmdline_config")
+    @mock.patch(DS_PATH + ".cmdline.read_initramfs_config")
     @mock.patch(DS_PATH + "._is_iscsi_root", return_value=True)
-    def test_network_cmdline(self, m_is_iscsi_root, m_cmdline_config):
+    def test_network_cmdline(self, m_is_iscsi_root, m_initramfs_config):
         """network_config should read kernel cmdline."""
         distro = mock.MagicMock()
         ds, _ = self._get_ds(distro=distro, patches={
@@ -145,15 +145,15 @@ class TestDataSourceOracle(test_helpers.CiTestCase):
                     MD_VER: {'system_uuid': self.my_uuid,
                              'meta_data': self.my_md}}}})
         ncfg = {'version': 1, 'config': [{'a': 'b'}]}
-        m_cmdline_config.return_value = ncfg
+        m_initramfs_config.return_value = ncfg
         self.assertTrue(ds._get_data())
         self.assertEqual(ncfg, ds.network_config)
-        m_cmdline_config.assert_called_once_with()
+        self.assertEqual([mock.call()], m_initramfs_config.call_args_list)
         self.assertFalse(distro.generate_fallback_config.called)
 
-    @mock.patch(DS_PATH + ".cmdline.read_kernel_cmdline_config")
+    @mock.patch(DS_PATH + ".cmdline.read_initramfs_config")
     @mock.patch(DS_PATH + "._is_iscsi_root", return_value=True)
-    def test_network_fallback(self, m_is_iscsi_root, m_cmdline_config):
+    def test_network_fallback(self, m_is_iscsi_root, m_initramfs_config):
         """test that fallback network is generated if no kernel cmdline."""
         distro = mock.MagicMock()
         ds, _ = self._get_ds(distro=distro, patches={
@@ -163,18 +163,17 @@ class TestDataSourceOracle(test_helpers.CiTestCase):
                     MD_VER: {'system_uuid': self.my_uuid,
                              'meta_data': self.my_md}}}})
         ncfg = {'version': 1, 'config': [{'a': 'b'}]}
-        m_cmdline_config.return_value = None
+        m_initramfs_config.return_value = None
         self.assertTrue(ds._get_data())
         ncfg = {'version': 1, 'config': [{'distro1': 'value'}]}
         distro.generate_fallback_config.return_value = ncfg
         self.assertEqual(ncfg, ds.network_config)
-        m_cmdline_config.assert_called_once_with()
+        self.assertEqual([mock.call()], m_initramfs_config.call_args_list)
         distro.generate_fallback_config.assert_called_once_with()
-        self.assertEqual(1, m_cmdline_config.call_count)
 
         # test that the result got cached, and the methods not re-called.
         self.assertEqual(ncfg, ds.network_config)
-        self.assertEqual(1, m_cmdline_config.call_count)
+        self.assertEqual(1, m_initramfs_config.call_count)
 
 
 @mock.patch(DS_PATH + "._read_system_uuid", return_value=str(uuid.uuid4()))