dhclient-hook: cleanups, tests and fix a bug on 'down' event.

I noticed a bug in dhclient_hook on the 'down' event, using 'is'
operator rather than '==' (if self.net_action is 'down').

This refactors/simplifies the code a bit for easier testing and adds
tests.  The reason for the rename of 'action' to 'event' is to just
be internally consistent.  The word and Namespace 'action' is used
by cloud-init main, so it was not really usable here.

Also adds a main which can easily be debugged with:
  CI_DHCP_HOOK_DATA_D=./my.d python -m cloudinit.dhclient_hook up eth0

1 files changed, 105 insertions, 0 deletions

diff --git a/cloudinit/tests/test_dhclient_hook.py b/cloudinit/tests/test_dhclient_hook.py
new file mode 100644
index 00000000..7aab8dd5
--- /dev/null
+++ b/cloudinit/tests/test_dhclient_hook.py
@@ -0,0 +1,105 @@
+# This file is part of cloud-init. See LICENSE file for license information.
+
+"""Tests for cloudinit.dhclient_hook."""
+
+from cloudinit import dhclient_hook as dhc
+from cloudinit.tests.helpers import CiTestCase, dir2dict, populate_dir
+
+import argparse
+import json
+import mock
+import os
+
+
+class TestDhclientHook(CiTestCase):
+
+    ex_env = {
+        'interface': 'eth0',
+        'new_dhcp_lease_time': '3600',
+        'new_host_name': 'x1',
+        'new_ip_address': '10.145.210.163',
+        'new_subnet_mask': '255.255.255.0',
+        'old_host_name': 'x1',
+        'PATH': '/usr/sbin:/usr/bin:/sbin:/bin',
+        'pid': '614',
+        'reason': 'BOUND',
+    }
+
+    # some older versions of dhclient put the same content,
+    # but in upper case with DHCP4_ instead of new_
+    ex_env_dhcp4 = {
+        'REASON': 'BOUND',
+        'DHCP4_dhcp_lease_time': '3600',
+        'DHCP4_host_name': 'x1',
+        'DHCP4_ip_address': '10.145.210.163',
+        'DHCP4_subnet_mask': '255.255.255.0',
+        'INTERFACE': 'eth0',
+        'PATH': '/usr/sbin:/usr/bin:/sbin:/bin',
+        'pid': '614',
+    }
+
+    expected = {
+        'dhcp_lease_time': '3600',
+        'host_name': 'x1',
+        'ip_address': '10.145.210.163',
+        'subnet_mask': '255.255.255.0'}
+
+    def setUp(self):
+        super(TestDhclientHook, self).setUp()
+        self.tmp = self.tmp_dir()
+
+    def test_handle_args(self):
+        """quick test of call to handle_args."""
+        nic = 'eth0'
+        args = argparse.Namespace(event=dhc.UP, interface=nic)
+        with mock.patch.dict("os.environ", clear=True, values=self.ex_env):
+            dhc.handle_args(dhc.NAME, args, data_d=self.tmp)
+        found = dir2dict(self.tmp + os.path.sep)
+        self.assertEqual([nic + ".json"], list(found.keys()))
+        self.assertEqual(self.expected, json.loads(found[nic + ".json"]))
+
+    def test_run_hook_up_creates_dir(self):
+        """If dir does not exist, run_hook should create it."""
+        subd = self.tmp_path("subdir", self.tmp)
+        nic = 'eth1'
+        dhc.run_hook(nic, 'up', data_d=subd, env=self.ex_env)
+        self.assertEqual(
+            set([nic + ".json"]), set(dir2dict(subd + os.path.sep)))
+
+    def test_run_hook_up(self):
+        """Test expected use of run_hook_up."""
+        nic = 'eth0'
+        dhc.run_hook(nic, 'up', data_d=self.tmp, env=self.ex_env)
+        found = dir2dict(self.tmp + os.path.sep)
+        self.assertEqual([nic + ".json"], list(found.keys()))
+        self.assertEqual(self.expected, json.loads(found[nic + ".json"]))
+
+    def test_run_hook_up_dhcp4_prefix(self):
+        """Test run_hook filters correctly with older DHCP4_ data."""
+        nic = 'eth0'
+        dhc.run_hook(nic, 'up', data_d=self.tmp, env=self.ex_env_dhcp4)
+        found = dir2dict(self.tmp + os.path.sep)
+        self.assertEqual([nic + ".json"], list(found.keys()))
+        self.assertEqual(self.expected, json.loads(found[nic + ".json"]))
+
+    def test_run_hook_down_deletes(self):
+        """down should delete the created json file."""
+        nic = 'eth1'
+        populate_dir(
+            self.tmp, {nic + ".json": "{'abcd'}", 'myfile.txt': 'text'})
+        dhc.run_hook(nic, 'down', data_d=self.tmp, env={'old_host_name': 'x1'})
+        self.assertEqual(
+            set(['myfile.txt']),
+            set(dir2dict(self.tmp + os.path.sep)))
+
+    def test_get_parser(self):
+        """Smoke test creation of get_parser."""
+        # cloud-init main uses 'action'.
+        event, interface = (dhc.UP, 'mynic0')
+        self.assertEqual(
+            argparse.Namespace(event=event, interface=interface,
+                               action=(dhc.NAME, dhc.handle_args)),
+            dhc.get_parser().parse_args([event, interface]))
+
+
+# vi: ts=4 expandtab