[watchmedo] Avoid zombie sub-processes when running shell-command without --wait (#897)
* [watchmedo] Avoid zombie sub-processes when running shell-command without --wait
* lint
* reference the issue rather than PR in the changelog
* avoid shlex.join which was added in Python 3.8
* increase test wait time
* try further increasing wait time to get tests passing on Windows
* fix is_process_running()
* still debugging on Windows...
* apparently Windows doesn't like shell-quoted Python executables
diff --git a/changelog.rst b/changelog.rst
index 747645c..7549fec 100644
--- a/changelog.rst
+++ b/changelog.rst
@@ -9,7 +9,8 @@
2022-xx-xx • `full history <https://github.com/gorakhargosh/watchdog/compare/v2.1.8...HEAD>`__
- [fsevents] Fix flakey test to assert that there are no errors when stopping the emitter.
-- [watchmedo] Make auto-restart restart the sub-process if it terminates. (`#896 <https://github.com/gorakhargosh/watchdog/pull/896>`__)
+- [watchmedo] Make ``auto-restart`` restart the sub-process if it terminates. (`#896 <https://github.com/gorakhargosh/watchdog/pull/896>`__)
+- [watchmedo] Avoid zombie sub-processes when running ``shell-command`` without ``--wait``. (`#405 <https://github.com/gorakhargosh/watchdog/issues/405>`__)
- Thanks to our beloved contributors: @samschott, @taleinat
2.1.8
diff --git a/src/watchdog/tricks/__init__.py b/src/watchdog/tricks/__init__.py
index 3303924..6e7eaf6 100644
--- a/src/watchdog/tricks/__init__.py
+++ b/src/watchdog/tricks/__init__.py
@@ -116,12 +116,14 @@
self.shell_command = shell_command
self.wait_for_process = wait_for_process
self.drop_during_process = drop_during_process
+
self.process = None
+ self._process_watchers = set()
def on_any_event(self, event):
from string import Template
- if self.drop_during_process and self.process and self.process.poll() is None:
+ if self.drop_during_process and self.is_process_running():
return
if event.is_directory:
@@ -151,6 +153,15 @@
self.process = subprocess.Popen(command, shell=True)
if self.wait_for_process:
self.process.wait()
+ else:
+ process_watcher = ProcessWatcher(self.process, None)
+ self._process_watchers.add(process_watcher)
+ process_watcher.process_termination_callback = \
+ functools.partial(self._process_watchers.discard, process_watcher)
+ process_watcher.start()
+
+ def is_process_running(self):
+ return self._process_watchers or (self.process is not None and self.process.poll() is None)
class AutoRestartTrick(Trick):
diff --git a/src/watchdog/utils/process_watcher.py b/src/watchdog/utils/process_watcher.py
index 800d7f8..f195764 100644
--- a/src/watchdog/utils/process_watcher.py
+++ b/src/watchdog/utils/process_watcher.py
@@ -1,5 +1,4 @@
import logging
-import time
from watchdog.utils import BaseThread
@@ -15,11 +14,10 @@
def run(self):
while True:
- if self.stopped_event.is_set():
- return
if self.popen_obj.poll() is not None:
break
- time.sleep(0.1)
+ if self.stopped_event.wait(timeout=0.1):
+ return
try:
self.process_termination_callback()
diff --git a/tests/test_0_watchmedo.py b/tests/test_0_watchmedo.py
index d9aaf3f..0f76e98 100644
--- a/tests/test_0_watchmedo.py
+++ b/tests/test_0_watchmedo.py
@@ -65,7 +65,7 @@
script = make_dummy_script(tmpdir)
a = AutoRestartTrick([sys.executable, script])
a.start()
- time.sleep(5)
+ time.sleep(3)
a.stop()
cap = capfd.readouterr()
assert '+++++ 0' in cap.out
@@ -74,6 +74,38 @@
# assert 'KeyboardInterrupt' in cap.err
+def test_shell_command_wait_for_completion(tmpdir, capfd):
+ from watchdog.events import FileModifiedEvent
+ from watchdog.tricks import ShellCommandTrick
+ import sys
+ import time
+ script = make_dummy_script(tmpdir, n=1)
+ command = " ".join([sys.executable, script])
+ trick = ShellCommandTrick(command, wait_for_process=True)
+ assert not trick.is_process_running()
+ start_time = time.monotonic()
+ trick.on_any_event(FileModifiedEvent("foo/bar.baz"))
+ elapsed = time.monotonic() - start_time
+ print(capfd.readouterr())
+ assert not trick.is_process_running()
+ assert elapsed >= 1
+
+
+def test_shell_command_subprocess_termination_nowait(tmpdir):
+ from watchdog.events import FileModifiedEvent
+ from watchdog.tricks import ShellCommandTrick
+ import sys
+ import time
+ script = make_dummy_script(tmpdir, n=1)
+ command = " ".join([sys.executable, script])
+ trick = ShellCommandTrick(command, wait_for_process=False)
+ assert not trick.is_process_running()
+ trick.on_any_event(FileModifiedEvent("foo/bar.baz"))
+ assert trick.is_process_running()
+ time.sleep(5)
+ assert not trick.is_process_running()
+
+
def test_auto_restart_subprocess_termination(tmpdir, capfd):
from watchdog.tricks import AutoRestartTrick
import sys
