cloud-init-dev team mailing list archive

[Igor Galić <i.galic@xxxxxxxxxxxxxx>]

Igor Galić has proposed merging ~i.galic/cloud-init:feax/ephemeral_connectivity into cloud-init:master.

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

For more details, see:
https://code.launchpad.net/~i.galic/cloud-init/+git/cloud-init/+merge/358876
-- 
Your team cloud-init commiters is requested to review the proposed merge of ~i.galic/cloud-init:feax/ephemeral_connectivity into cloud-init:master.

diff --git a/cloudinit/net/__init__.py b/cloudinit/net/__init__.py
index ad98a59..c1f9c13 100644
--- a/cloudinit/net/__init__.py
+++ b/cloudinit/net/__init__.py
@@ -12,6 +12,7 @@ import re
 
 from cloudinit.net.network_state import mask_to_net_prefix
 from cloudinit import util
+from cloudinit.url_helper import readurl
 
 LOG = logging.getLogger(__name__)
 SYS_CLASS_NET = "/sys/class/net/"
@@ -647,16 +648,28 @@ def get_ib_hwaddrs_by_interface():
     return ret
 
 
+def has_url_connectivity(url):
+    """Return true when the instance has access to the provided URL"""
+    try:
+        readurl(url, timeout=5)
+    except UrlError:
+        return False
+    return True
+
+
 class EphemeralIPv4Network(object):
     """Context manager which sets up temporary static network configuration.
 
-    No operations are performed if the provided interface is already connected.
+    No operations are performed if the provided interface already has the
+    specified configuration.
+    This can be verified with the connectivity_url.
     If unconnected, bring up the interface with valid ip, prefix and broadcast.
     If router is provided setup a default route for that interface. Upon
     context exit, clean up the interface leaving no configuration behind.
     """
 
-    def __init__(self, interface, ip, prefix_or_mask, broadcast, router=None):
+    def __init__(self, interface, ip, prefix_or_mask, broadcast, router=None,
+                 connectivity_url=None):
         """Setup context manager and validate call signature.
 
         @param interface: Name of the network interface to bring up.
@@ -665,6 +678,8 @@ class EphemeralIPv4Network(object):
             prefix.
         @param broadcast: Broadcast address for the IPv4 network.
         @param router: Optionally the default gateway IP.
+        @param connectivity_url: Optionally, a URL to verify if a usable
+           connection already exists.
         """
         if not all([interface, ip, prefix_or_mask, broadcast]):
             raise ValueError(
@@ -675,6 +690,8 @@ class EphemeralIPv4Network(object):
         except ValueError as e:
             raise ValueError(
                 'Cannot setup network: {0}'.format(e))
+
+        self.connectivity_url = connectivity_url
         self.interface = interface
         self.ip = ip
         self.broadcast = broadcast
@@ -683,6 +700,13 @@ class EphemeralIPv4Network(object):
 
     def __enter__(self):
         """Perform ephemeral network setup if interface is not connected."""
+        if self.connectivity_url:
+            if has_url_connectivity(self.connectivity_url):
+                LOG.debug(
+                    'Skip ephemeral network setup, instance has connectivity'
+                    ' to %s', self.connectivity_url)
+                return
+
         self._bringup_device()
         if self.router:
             self._bringup_router()
@@ -692,6 +716,9 @@ class EphemeralIPv4Network(object):
         for cmd in self.cleanup_cmds:
             util.subp(cmd, capture=True)
 
+    def _connectivity_ceck():
+        """Perform connectivity check using connectivity_url"""
+
     def _delete_address(self, address, prefix):
         """Perform the ip command to remove the specified address."""
         util.subp(
diff --git a/cloudinit/net/tests/test_init.py b/cloudinit/net/tests/test_init.py
index 58e0a59..996296f 100644
--- a/cloudinit/net/tests/test_init.py
+++ b/cloudinit/net/tests/test_init.py
@@ -458,6 +458,22 @@ class TestEphemeralIPV4Network(CiTestCase):
             self.assertEqual(expected_setup_calls, m_subp.call_args_list)
         m_subp.assert_has_calls(expected_teardown_calls)
 
+    @mock.patch('cloudinit.config.cc_chef.url_helper.readurl')
+    def test_ephemeral_ipv4_no_network_if_url_connectivity(
+            self, m_readurl, m_subp):
+        """No network setup is performed if we can successfully connect to
+        connectivity_url."""
+        params = {
+            'interface': 'eth0', 'ip': '192.168.2.2',
+            'prefix_or_mask': '255.255.255.0', 'broadcast': '192.168.2.255',
+            'connectivity_url': 'http://example.org/index.html'}
+
+        with net.EphemeralIPv4Network(**params):
+            self.assertEqual([mock.call('http://example.org/index.html',
+                                        timeout=5)], m_readurl.call_args_list)
+        # Ensure that no teardown happens:
+        m_subp.assert_has_calls([])
+
     def test_ephemeral_ipv4_network_noop_when_configured(self, m_subp):
         """EphemeralIPv4Network handles exception when address is setup.