Merge "Remove psutil dependency"

neutron/agent/linux/async_process.py

@@ -18,7 +18,6 @@ import eventlet
 import eventlet.event
 import eventlet.queue
 import eventlet.timeout
-import psutil
 
 from neutron.agent.linux import utils
 from neutron.openstack.common import log as logging
@@ -141,12 +140,18 @@ class AsyncProcess(object):
         # die is to target the child process directly.
         if self.root_helper:
             try:
-                # This assumes that there are not multiple children in any
-                # level of the process tree under the parent process.
-                pid = psutil.Process(
-                    self._process.pid).get_children(recursive=True)[-1].pid
-            except (psutil.NoSuchProcess, IndexError):
-                pid = None
+                pid = utils.find_child_pids(pid)[0]
+            except IndexError:
+                # Process is already dead
+                return None
+            while True:
+                try:
+                    # We shouldn't have more than one child per process
+                    # so keep getting the children of the first one
+                    pid = utils.find_child_pids(pid)[0]
+                except IndexError:
+                    # Last process in the tree, return it
+                    break
         return pid
 
     def _kill_process(self, pid):

neutron/agent/linux/utils.py

@@ -108,3 +108,18 @@ def replace_file(file_name, data):
     tmp_file.close()
     os.chmod(tmp_file.name, 0o644)
     os.rename(tmp_file.name, file_name)
+
+
+def find_child_pids(pid):
+    """Retrieve a list of the pids of child processes of the given pid."""
+
+    try:
+        raw_pids = execute(['ps', '--ppid', pid, '-o', 'pid='])
+    except RuntimeError as e:
+        # Exception has already been logged by execute
+        no_children_found = 'Exit code: 1' in str(e)
+        if no_children_found:
+            return []
+        # Unexpected errors are the responsibility of the caller
+        raise
+    return [x.strip() for x in raw_pids.split('\n') if x.strip()]

neutron/tests/unit/agent/linux/test_async_process.py

@@ -14,8 +14,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import collections
-
 import eventlet.event
 import eventlet.queue
 import eventlet.timeout
@@ -187,19 +185,20 @@ class TestAsyncProcess(base.BaseTestCase):
 
     def _test__get_pid_to_kill(self, expected=_marker,
                                root_helper=None, pids=None):
+        def _find_child_pids(x):
+            if not pids:
+                return []
+            pids.pop(0)
+            return pids
+
         if root_helper:
             self.proc.root_helper = root_helper
 
-        xpid = collections.namedtuple('xpid', ['pid'])
-        xpids = [xpid(pid) for pid in pids or []]
-
         with mock.patch.object(self.proc, '_process') as mock_process:
             with mock.patch.object(mock_process, 'pid') as mock_pid:
-                with mock.patch('psutil.Process') as mock_ps_process:
-                    instance = mock_ps_process.return_value
-                    instance.get_children.return_value = xpids
+                with mock.patch.object(utils, 'find_child_pids',
+                                       side_effect=_find_child_pids):
                     actual = self.proc._get_pid_to_kill()
-
         if expected is _marker:
             expected = mock_pid
         self.assertEqual(expected, actual)
@@ -208,7 +207,8 @@ class TestAsyncProcess(base.BaseTestCase):
         self._test__get_pid_to_kill()
 
     def test__get_pid_to_kill_returns_child_pid_with_root_helper(self):
-        self._test__get_pid_to_kill(expected='1', pids=['1'], root_helper='a')
+        self._test__get_pid_to_kill(expected='2', pids=['1', '2'],
+                                    root_helper='a')
 
     def test__get_pid_to_kill_returns_last_child_pid_with_root_Helper(self):
         self._test__get_pid_to_kill(expected='3', pids=['1', '2', '3'],

neutron/tests/unit/test_agent_linux_utils.py

@@ -17,6 +17,7 @@
 
 import fixtures
 import mock
+import testtools
 
 from neutron.agent.linux import utils
 from neutron.tests import base
@@ -106,3 +107,25 @@ class AgentUtilsReplaceFile(base.BaseTestCase):
                     ntf.assert_has_calls(expected)
                     chmod.assert_called_once_with('/baz', 0o644)
                     rename.assert_called_once_with('/baz', '/foo')
+
+
+class TestFindChildPids(base.BaseTestCase):
+
+    def test_returns_empty_list_for_exit_code_1(self):
+        with mock.patch.object(utils, 'execute',
+                               side_effect=RuntimeError('Exit code: 1')):
+            self.assertEqual(utils.find_child_pids(-1), [])
+
+    def test_returns_empty_list_for_no_output(self):
+        with mock.patch.object(utils, 'execute', return_value=''):
+            self.assertEqual(utils.find_child_pids(-1), [])
+
+    def test_returns_list_of_child_process_ids_for_good_ouput(self):
+        with mock.patch.object(utils, 'execute', return_value=' 123 \n 185\n'):
+            self.assertEqual(utils.find_child_pids(-1), ['123', '185'])
+
+    def test_raises_unknown_exception(self):
+        with testtools.ExpectedException(RuntimeError):
+            with mock.patch.object(utils, 'execute',
+                                   side_effect=RuntimeError()):
+                utils.find_child_pids(-1)

requirements.txt

@@ -16,7 +16,6 @@ jsonrpclib
 Jinja2
 kombu>=2.4.8
 netaddr>=0.7.6
-psutil>=0.6.1,<1.0
 python-neutronclient>=2.3.0,<3
 SQLAlchemy>=0.7.8,<=0.7.99
 WebOb>=1.2.3,<1.3