power_state: support 'condition' argument

  
  if 'condition' is provided to config in power_state, then
  consult it before powering off.
  
  This allows the user to shut down only if a condition is met, and
  leave the system in a debuggable state otherwise.
  
  An example is as simple as:
   power_state:
     mode: poweroff
     condition: ['sh', '-c', '[ -f /disable-poweroff ]']

1 files changed, 44 insertions, 4 deletions

diff --git a/tests/unittests/test_handler/test_handler_power_state.py b/tests/unittests/test_handler/test_handler_power_state.py
index 2f86b8f8..5687b10d 100644
--- a/tests/unittests/test_handler/test_handler_power_state.py
+++ b/tests/unittests/test_handler/test_handler_power_state.py
@@ -1,6 +1,9 @@
+import sys
+
 from cloudinit.config import cc_power_state_change as psc
 
 from .. import helpers as t_help
+from ..helpers import mock
 
 
 class TestLoadPowerState(t_help.TestCase):
@@ -9,12 +12,12 @@ class TestLoadPowerState(t_help.TestCase):
 
     def test_no_config(self):
         # completely empty config should mean do nothing
-        (cmd, _timeout) = psc.load_power_state({})
+        (cmd, _timeout, _condition) = psc.load_power_state({})
         self.assertEqual(cmd, None)
 
     def test_irrelevant_config(self):
         # no power_state field in config should return None for cmd
-        (cmd, _timeout) = psc.load_power_state({'foo': 'bar'})
+        (cmd, _timeout, _condition) = psc.load_power_state({'foo': 'bar'})
         self.assertEqual(cmd, None)
 
     def test_invalid_mode(self):
@@ -53,23 +56,60 @@ class TestLoadPowerState(t_help.TestCase):
     def test_no_message(self):
         # if message is not present, then no argument should be passed for it
         cfg = {'power_state': {'mode': 'poweroff'}}
-        (cmd, _timeout) = psc.load_power_state(cfg)
+        (cmd, _timeout, _condition) = psc.load_power_state(cfg)
         self.assertNotIn("", cmd)
         check_lps_ret(psc.load_power_state(cfg))
         self.assertTrue(len(cmd) == 3)
 
+    def test_condition_null_raises(self):
+        cfg = {'power_state': {'mode': 'poweroff', 'condition': None}}
+        self.assertRaises(TypeError, psc.load_power_state, cfg)
+
+    def test_condition_default_is_true(self):
+        cfg = {'power_state': {'mode': 'poweroff'}}
+        _cmd, _timeout, cond = psc.load_power_state(cfg)
+        self.assertEqual(cond, True)
+
+
+class TestCheckCondition(t_help.TestCase):
+    def cmd_with_exit(self, rc):
+        return([sys.executable, '-c', 'import sys; sys.exit(%s)' % rc])
+        
+    def test_true_is_true(self):
+        self.assertEqual(psc.check_condition(True), True)
+
+    def test_false_is_false(self):
+        self.assertEqual(psc.check_condition(False), False)
+
+    def test_cmd_exit_zero_true(self):
+        self.assertEqual(psc.check_condition(self.cmd_with_exit(0)), True)
+
+    def test_cmd_exit_one_false(self):
+        self.assertEqual(psc.check_condition(self.cmd_with_exit(1)), False)
+
+    def test_cmd_exit_nonzero_warns(self):
+        mocklog = mock.Mock()
+        self.assertEqual(
+            psc.check_condition(self.cmd_with_exit(2), mocklog), False)
+        self.assertEqual(mocklog.warn.call_count, 1)
+
+
 
 def check_lps_ret(psc_return, mode=None):
-    if len(psc_return) != 2:
+    if len(psc_return) != 3:
         raise TypeError("length returned = %d" % len(psc_return))
 
     errs = []
     cmd = psc_return[0]
     timeout = psc_return[1]
+    condition = psc_return[2]
 
     if 'shutdown' not in psc_return[0][0]:
         errs.append("string 'shutdown' not in cmd")
 
+    if 'condition' is None:
+        errs.append("condition was not returned")
+
     if mode is not None:
         opt = {'halt': '-H', 'poweroff': '-P', 'reboot': '-r'}[mode]
         if opt not in psc_return[0]: