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[Chad Smith <chad.smith@xxxxxxxxxxxxx>]

Chad Smith has proposed merging ~chad.smith/cloud-init:aws-ipv6-dhcp-support into cloud-init:master.

Requested reviews:
  cloud-init commiters (cloud-init-dev)

For more details, see:
https://code.launchpad.net/~chad.smith/cloud-init/+git/cloud-init/+merge/329499

ec2: Add IPv6 dhcp support to Ec2DataSource.

DataSourceEc2 now parses the metadata for each nic to determine if configured for ipv6 and/or ipv4 addresses. In AWS for metadata version 2016-09-02, nics configured for ipv4 or ipv6 addresses will have non-zero values stored in metadata at network/interfaces/macs/<MAC>/vpc-ipv4-cidr-blocks or vpc-ipv6-cidr-blocks respectively. A new DataSourceEc2.network_config property is added which parses the metadata and renders a network version 1 dictionary representing both dhcp4 and dhcp6 configuration for associated nics.

The network configuration returned from the datasource will also 'pin' the nic name to the name presented on the instance for each nic.
-- 
Your team cloud-init commiters is requested to review the proposed merge of ~chad.smith/cloud-init:aws-ipv6-dhcp-support into cloud-init:master.

diff --git a/cloudinit/sources/DataSourceEc2.py b/cloudinit/sources/DataSourceEc2.py
index 8e5f8ee..5d717ad 100644
--- a/cloudinit/sources/DataSourceEc2.py
+++ b/cloudinit/sources/DataSourceEc2.py
@@ -57,6 +57,8 @@ class DataSourceEc2(sources.DataSource):
 
     _cloud_platform = None
 
+    _network_config = None  # Used for caching calculated network config v1
+
     # Whether we want to get network configuration from the metadata service.
     get_network_metadata = False
 
@@ -279,6 +281,15 @@ class DataSourceEc2(sources.DataSource):
                 util.get_cfg_by_path(cfg, STRICT_ID_PATH, STRICT_ID_DEFAULT),
                 cfg)
 
+    @property
+    def network_config(self):
+        """Return a network config dict for rendering ENI or netplan files."""
+        if self._network_config is None:
+            if self.metadata is not None:
+                self._network_config = convert_ec2_metadata_network_config(
+                    self.metadata)
+        return self._network_config
+
     def _crawl_metadata(self):
         """Crawl metadata service when available.
 
@@ -423,6 +434,33 @@ def _collect_platform_data():
     return data
 
 
+def convert_ec2_metadata_network_config(metadata=None, macs_to_nics=None):
+    """Convert ec2 metadata to network config version 1 data dict.
+
+    @param: metadata: Dictionary of metadata crawled from EC2 metadata url.
+    @param: macs_to_name: Optional dict mac addresses and the nic name. If
+       not provided, get_interfaces_by_mac is called to get it from the OS.
+
+    @return A dict of network config version 1 based on the metadata and macs.
+    """
+    netcfg = {'version': 1, 'config': []}
+    if not macs_to_nics:
+        macs_to_nics = net.get_interfaces_by_mac()
+    macs_metadata = metadata['network']['interfaces']['macs']
+    for mac, nic_name in macs_to_nics.items():
+        nic_metadata = macs_metadata.get(mac)
+        if not nic_metadata:
+            continue  # Not a physical nic represented in metadata
+        nic_cfg = {'type': 'physical', 'name': nic_name, 'subnets': []}
+        nic_cfg['mac_address'] = mac
+        if nic_metadata.get('vpc-ipv4-cidr-blocks'):
+            nic_cfg['subnets'].append({'type': 'dhcp4'})
+        if nic_metadata.get('vpc-ipv6-cidr-blocks'):
+            nic_cfg['subnets'].append({'type': 'dhcp6'})
+        netcfg['config'].append(nic_cfg)
+    return netcfg
+
+
 # Used to match classes to dependencies
 datasources = [
     (DataSourceEc2Local, (sources.DEP_FILESYSTEM,)),  # Run at init-local
diff --git a/tests/unittests/test_datasource/test_ec2.py b/tests/unittests/test_datasource/test_ec2.py
index 33d0261..6d62449 100644
--- a/tests/unittests/test_datasource/test_ec2.py
+++ b/tests/unittests/test_datasource/test_ec2.py
@@ -1,5 +1,6 @@
 # This file is part of cloud-init. See LICENSE file for license information.
 
+import copy
 import httpretty
 import mock
 
@@ -195,6 +196,34 @@ class TestEc2(test_helpers.HttprettyTestCase):
         return ds
 
     @httpretty.activate
+    def test_network_config_property_returns_version_1_network_data(self):
+        """network_config property returns network version 1 for metadata."""
+        ds = self._setup_ds(
+            platform_data=self.valid_platform_data,
+            sys_cfg={'datasource': {'Ec2': {'strict_id': True}}},
+            md=DEFAULT_METADATA)
+        ds.get_data()
+        mac1 = '06:17:04:d7:26:09'  # Defined in DEFAULT_METADATA
+        expected = {'version': 1, 'config': [
+            {'mac_address': '06:17:04:d7:26:09', 'name': 'eth9',
+             'subnets': [{'type': 'dhcp4'}, {'type': 'dhcp6'}],
+             'type': 'physical'}]}
+        patch_path = (
+            'cloudinit.sources.DataSourceEc2.net.get_interfaces_by_mac')
+        with mock.patch(patch_path) as m_get_interfaces_by_mac:
+            m_get_interfaces_by_mac.return_value = {mac1: 'eth9'}
+            self.assertEqual(expected, ds.network_config)
+
+    def test_network_config_property_is_cached_in_datasource(self):
+        """network_config property is cached in DataSourceEc2."""
+        ds = self._setup_ds(
+            platform_data=self.valid_platform_data,
+            sys_cfg={'datasource': {'Ec2': {'strict_id': True}}},
+            md=DEFAULT_METADATA)
+        ds._network_config = {'cached': 'data'}
+        self.assertEqual({'cached': 'data'}, ds.network_config)
+
+    @httpretty.activate
     @mock.patch('cloudinit.net.dhcp.maybe_perform_dhcp_discovery')
     def test_valid_platform_with_strict_true(self, m_dhcp):
         """Valid platform data should return true with strict_id true."""
@@ -287,4 +316,72 @@ class TestEc2(test_helpers.HttprettyTestCase):
         self.assertIn('Crawl of metadata service took', self.logs.getvalue())
 
 
+class TestConvertEc2MetadataNetworkConfig(test_helpers.CiTestCase):
+
+    def setUp(self):
+        super(TestConvertEc2MetadataNetworkConfig, self).setUp()
+        self.mac1 = '06:17:04:d7:26:09'
+        self.network_metadata = {
+            'network': {'interfaces': {'macs': {
+                self.mac1: {'vpc-ipv4-cidr-blocks': '172.31.0.0/16'}}}}}
+
+    def test_convert_ec2_metadata_network_config_skips_absent_macs(self):
+        """Any mac absent from metadata is skipped by network config."""
+        macs_to_nics = {self.mac1: 'eth9', 'DE:AD:BE:EF:FF:FF': 'vitualnic2'}
+
+        # DE:AD:BE:EF:FF:FF represented by OS but not in metadata
+        expected = {'version': 1, 'config': [
+            {'mac_address': self.mac1, 'type': 'physical',
+             'name': 'eth9', 'subnets': [{'type': 'dhcp4'}]}]}
+        self.assertEqual(
+            expected,
+            ec2.convert_ec2_metadata_network_config(
+                self.network_metadata, macs_to_nics))
+
+    def test_convert_ec2_metadata_network_config_handles_only_dhcp6(self):
+        """Config dhcp6 when vpc-ipv6-cidr-blocks is in metadata for a mac."""
+        macs_to_nics = {self.mac1: 'eth9'}
+        network_metadata_ipv6 = copy.deepcopy(self.network_metadata)
+        nic1_metadata = (
+            network_metadata_ipv6['network']['interfaces']['macs'][self.mac1])
+        nic1_metadata['vpc-ipv6-cidr-blocks'] = '2600:1f16:aeb:b20b::/64'
+        nic1_metadata.pop('vpc-ipv4-cidr-blocks')
+        expected = {'version': 1, 'config': [
+            {'mac_address': self.mac1, 'type': 'physical',
+             'name': 'eth9', 'subnets': [{'type': 'dhcp6'}]}]}
+        self.assertEqual(
+            expected,
+            ec2.convert_ec2_metadata_network_config(
+                network_metadata_ipv6, macs_to_nics))
+
+    def test_convert_ec2_metadata_network_config_handles_dhcp4_and_dhcp6(self):
+        """Config both dhcp4 and dhcp6 when both vpc-ipv6 and ipv4 exists."""
+        macs_to_nics = {self.mac1: 'eth9'}
+        network_metadata_both = copy.deepcopy(self.network_metadata)
+        nic1_metadata = (
+            network_metadata_both['network']['interfaces']['macs'][self.mac1])
+        nic1_metadata['vpc-ipv6-cidr-blocks'] = '2600:1f16:aeb:b20b::/64'
+        expected = {'version': 1, 'config': [
+            {'mac_address': self.mac1, 'type': 'physical',
+             'name': 'eth9',
+             'subnets': [{'type': 'dhcp4'}, {'type': 'dhcp6'}]}]}
+        self.assertEqual(
+            expected,
+            ec2.convert_ec2_metadata_network_config(
+                network_metadata_both, macs_to_nics))
+
+    def test_convert_ec2_metadata_gets_macs_from_get_interfaces_by_mac(self):
+        """Convert Ec2 Metadata calls get_interfaces_by_mac by default."""
+        expected = {'version': 1, 'config': [
+            {'mac_address': self.mac1, 'type': 'physical',
+             'name': 'eth9',
+             'subnets': [{'type': 'dhcp4'}]}]}
+        patch_path = (
+            'cloudinit.sources.DataSourceEc2.net.get_interfaces_by_mac')
+        with mock.patch(patch_path) as m_get_interfaces_by_mac:
+            m_get_interfaces_by_mac.return_value = {self.mac1: 'eth9'}
+            self.assertEqual(
+                expected,
+                ec2.convert_ec2_metadata_network_config(self.network_metadata))
+
 # vi: ts=4 expandtab