Ensure a single running instance of edit monitor
This cl ensures at most 1 instance of edit monitor running from the
same binary by killing any existing instance before starting.
Specifically, When an edit monitor process starts, it will write a pidfile containing its pid and if such pidfile already exists (which means there's another instance there), it will read the pid contained in that pidfile and kill the corresponding process first.
Test: atst daemon_manager_test
bug: 365617369
Change-Id: I76954344df649aa79a6ef07ce55a62985decdb53
diff --git a/tools/edit_monitor/daemon_manager_test.py b/tools/edit_monitor/daemon_manager_test.py
index 5be4bee..214b038 100644
--- a/tools/edit_monitor/daemon_manager_test.py
+++ b/tools/edit_monitor/daemon_manager_test.py
@@ -33,7 +33,7 @@
)
-def example_daemon(output_file):
+def simple_daemon(output_file):
with open(output_file, 'w') as f:
f.write('running daemon target')
@@ -69,29 +69,62 @@
tempfile.tempdir = self.original_tempdir
super().tearDown()
- def test_start_success(self):
- damone_output_file = tempfile.NamedTemporaryFile(
- dir=self.working_dir.name, delete=False
+ def test_start_success_with_no_existing_instance(self):
+ self.assert_run_simple_daemon_success()
+
+ def test_start_success_with_existing_instance_running(self):
+ # Create a long running subprocess
+ p = multiprocessing.Process(target=long_running_daemon)
+ p.start()
+
+ # Create a pidfile with the subprocess pid
+ pid_file_path_dir = pathlib.Path(self.working_dir.name).joinpath(
+ 'edit_monitor'
)
- dm = daemon_manager.DaemonManager(
- TEST_BINARY_FILE,
- daemon_target=example_daemon,
- daemon_args=(damone_output_file.name,),
+ pid_file_path_dir.mkdir(parents=True, exist_ok=True)
+ with open(pid_file_path_dir.joinpath(TEST_PID_FILE_PATH), 'w') as f:
+ f.write(str(p.pid))
+
+ self.assert_run_simple_daemon_success()
+ p.terminate()
+
+ def test_start_success_with_existing_instance_already_dead(self):
+ # Create a pidfile with pid that does not exist.
+ pid_file_path_dir = pathlib.Path(self.working_dir.name).joinpath(
+ 'edit_monitor'
)
+ pid_file_path_dir.mkdir(parents=True, exist_ok=True)
+ with open(pid_file_path_dir.joinpath(TEST_PID_FILE_PATH), 'w') as f:
+ f.write('123456')
+
+ self.assert_run_simple_daemon_success()
+
+ def test_start_success_with_existing_instance_from_different_binary(self):
+ # First start an instance based on "some_binary_path"
+ existing_dm = daemon_manager.DaemonManager(
+ "some_binary_path",
+ daemon_target=long_running_daemon,
+ )
+ existing_dm.start()
+
+ self.assert_run_simple_daemon_success()
+ existing_dm.stop()
+
+ @mock.patch('os.kill')
+ def test_start_failed_to_kill_existing_instance(self, mock_kill):
+ mock_kill.side_effect = OSError('Unknown OSError')
+ pid_file_path_dir = pathlib.Path(self.working_dir.name).joinpath(
+ 'edit_monitor'
+ )
+ pid_file_path_dir.mkdir(parents=True, exist_ok=True)
+ with open(pid_file_path_dir.joinpath(TEST_PID_FILE_PATH), 'w') as f:
+ f.write('123456')
+
+ dm = daemon_manager.DaemonManager(TEST_BINARY_FILE)
dm.start()
- dm.daemon_process.join()
- # Verifies the expected pid file is created.
- expected_pid_file_path = pathlib.Path(self.working_dir.name).joinpath(
- 'edit_monitor', TEST_PID_FILE_PATH
- )
- self.assertEqual(dm.pid_file_path, expected_pid_file_path)
- self.assertTrue(expected_pid_file_path.exists())
-
- # Verifies the daemon process is executed successfully.
- with open(damone_output_file.name, 'r') as f:
- contents = f.read()
- self.assertEqual(contents, 'running daemon target')
+ # Verify no daemon process is started.
+ self.assertIsNone(dm.daemon_process)
def test_start_failed_to_write_pidfile(self):
pid_file_path_dir = pathlib.Path(self.working_dir.name).joinpath(
@@ -151,6 +184,29 @@
self.assert_no_subprocess_running()
self.assertTrue(dm.pid_file_path.exists())
+ def assert_run_simple_daemon_success(self):
+ damone_output_file = tempfile.NamedTemporaryFile(
+ dir=self.working_dir.name, delete=False
+ )
+ dm = daemon_manager.DaemonManager(
+ TEST_BINARY_FILE,
+ daemon_target=simple_daemon,
+ daemon_args=(damone_output_file.name,),
+ )
+ dm.start()
+ dm.daemon_process.join()
+
+ # Verifies the expected pid file is created.
+ expected_pid_file_path = pathlib.Path(self.working_dir.name).joinpath(
+ 'edit_monitor', TEST_PID_FILE_PATH
+ )
+ self.assertTrue(expected_pid_file_path.exists())
+
+ # Verify the daemon process is executed successfully.
+ with open(damone_output_file.name, 'r') as f:
+ contents = f.read()
+ self.assertEqual(contents, 'running daemon target')
+
def assert_no_subprocess_running(self):
child_pids = self._get_child_processes(os.getpid())
for child_pid in child_pids: