Merge lp:~wenjianhn/charm-helpers/get-addr-in-net into lp:charm-helpers

[Jian Wen]

This patch adds a networking helper to get an IPv4 address in a
specified network.

[James Page (james-page)]

review: Approve

=== added file 'charmhelpers/contrib/network/ip.py'
--- charmhelpers/contrib/network/ip.py	1970-01-01 00:00:00 +0000
+++ charmhelpers/contrib/network/ip.py	2013-12-18 05:53:32 +0000
@@ -0,0 +1,69 @@
+import sys
+
+from charmhelpers.fetch import apt_install
+from charmhelpers.core.hookenv import (
+    ERROR, log,
+)
+
+try:
+    import netifaces
+except ImportError:
+    apt_install('python-netifaces')
+    import netifaces
+
+try:
+    import netaddr
+except ImportError:
+    apt_install('python-netaddr')
+    import netaddr
+
+
+def _validate_cidr(network):
+    try:
+        netaddr.IPNetwork(network)
+    except (netaddr.core.AddrFormatError, ValueError):
+        raise ValueError("Network (%s) is not in CIDR presentation format" %
+                         network)
+
+
+def get_address_in_network(network, fallback=None, fatal=False):
+    """
+    Get an IPv4 address within the network from the host.
+
+    Args:
+        network (str): CIDR presentation format. For example,
+                       '192.168.1.0/24'.
+        fallback (str): If no address is found, return fallback.
+        fatal (boolean): If no address is found, fallback is not
+                         set and fatal is True then exit(1).
+    """
+
+    def not_found_error_out():
+        log("No IP address found in network: %s" % network,
+            level=ERROR)
+        sys.exit(1)
+
+    if network is None:
+        if fallback is not None:
+            return fallback
+        else:
+            if fatal:
+                not_found_error_out()
+
+    _validate_cidr(network)
+    for iface in netifaces.interfaces():
+        addresses = netifaces.ifaddresses(iface)
+        if netifaces.AF_INET in addresses:
+            addr = addresses[netifaces.AF_INET][0]['addr']
+            netmask = addresses[netifaces.AF_INET][0]['netmask']
+            cidr = netaddr.IPNetwork("%s/%s" % (addr, netmask))
+            if cidr in netaddr.IPNetwork(network):
+                return str(cidr.ip)
+
+    if fallback is not None:
+        return fallback
+
+    if fatal:
+        not_found_error_out()
+
+    return None
 
=== modified file 'test_requirements.txt'
--- test_requirements.txt	2013-05-22 08:12:53 +0000
+++ test_requirements.txt	2013-12-18 05:53:32 +0000
@@ -16,3 +16,5 @@
 testtools==0.9.31
 Tempita==0.5.1
 bzr+http://bazaar.launchpad.net/~yellow/python-shelltoolbox/trunk@17#egg=shelltoolbox
+netifaces==0.6
+netaddr==0.7.5
 
=== added file 'tests/contrib/network/test_ip.py'
--- tests/contrib/network/test_ip.py	1970-01-01 00:00:00 +0000
+++ tests/contrib/network/test_ip.py	2013-12-18 05:53:32 +0000
@@ -0,0 +1,81 @@
+import subprocess
+import unittest
+
+import mock
+import netifaces
+
+import charmhelpers.contrib.network.ip as net_ip
+
+
+class IPTest(unittest.TestCase):
+
+    def test_get_address_in_network_with_invalid_net(self):
+        for net in ['192.168.300/22', '192.168.1.0/2a', '2.a']:
+            self.assertRaises(ValueError,
+                              net_ip.get_address_in_network,
+                              net)
+
+    def _test_get_address_in_network(self, expect_ip_addr,
+                                     network, fallback=None, fatal=False):
+
+        def side_effect(iface):
+            ffff = 'ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff'
+            results = {'lo': {17: [{'peer': '00:00:00:00:00:00',
+                                    'addr': '00:00:00:00:00:00'}],
+                              2: [{'peer': '127.0.0.1', 'netmask':
+                                   '255.0.0.0', 'addr': '127.0.0.1'}],
+                              10: [{'netmask': ffff,
+                                    'addr': '::1'}]
+                          },
+                       'eth0': {17: [{'broadcast': 'ff:ff:ff:ff:ff:ff',
+                                      'addr': '28:92:4a:19:8c:e8'}]
+                            },
+                       'eth2': {17: [{'broadcast': 'ff:ff:ff:ff:ff:ff',
+                                      'addr': 'e0:06:e6:41:dd:dd'}],
+                                2: [{'broadcast': '192.168.1.255',
+                                     'netmask': '255.255.255.0',
+                                     'addr': '192.168.1.108'}],
+                                10: [{'netmask': 'ffff:ffff:ffff:ffff::',
+                                      'addr': 'fe80::e206:e6ff:fe41:dddd%eth2'}
+                                 ]
+                            },
+            }
+            return results[iface]
+
+        with mock.patch.object(netifaces, 'interfaces') as interfaces:
+            interfaces.return_value = ['lo', 'eth0', 'eth2']
+            with mock.patch.object(netifaces, 'ifaddresses') as ifaddresses:
+                ifaddresses.side_effect = side_effect
+                if not fatal:
+                    self.assertEqual(expect_ip_addr,
+                                     net_ip.get_address_in_network(
+                                         network, fallback, fatal))
+                else:
+                    net_ip.get_address_in_network(network, fallback, fatal)
+
+    @mock.patch.object(subprocess, 'call')
+    def test_get_address_in_network_with_none(self, popen):
+        fallback = '10.10.10.10'
+        self.assertEqual(fallback,
+                         net_ip.get_address_in_network(None, fallback))
+
+        self.assertRaises(SystemExit, self._test_get_address_in_network,
+                          None, None, fatal=True)
+
+    def test_get_address_in_network_works(self):
+        self._test_get_address_in_network('192.168.1.108', '192.168.1.0/24')
+
+    def test_get_address_in_network_with_non_existent_net(self):
+        self._test_get_address_in_network(None, '172.16.0.0/16')
+
+    def test_get_address_in_network_fallback_works(self):
+        fallback = '10.10.0.0'
+        self._test_get_address_in_network(fallback, '172.16.0.0/16', fallback)
+
+    @mock.patch.object(subprocess, 'call')
+    def test_get_address_in_network_not_found_fatal(self, popen):
+        self.assertRaises(SystemExit, self._test_get_address_in_network,
+                          None, '172.16.0.0/16', fatal=True)
+
+    def test_get_address_in_network_not_found_not_fatal(self):
+        self._test_get_address_in_network(None, '172.16.0.0/16', fatal=False)