pypi cproto（chrome 调试客户端）在退出时挂起

Question

Using https://pypi.org/project/cproto/, attached to Chrome 运行ning headless in a Docker container，我发现它时不时会卡住（下面引用的例子不可靠——您可能需要运行几次):

$ python3
Python 3.6.8 (default, Jan 14 2019, 11:02:34) 
[GCC 8.0.1 20180414 (experimental) [trunk revision 259383]] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cproto
>>> cp = cproto.CProto()   # localhost:9222 == my Chrome container
>>> cp.close()
>>> exit()
^CException ignored in: <module 'threading' from '/usr/lib/python3.6/threading.py'>
Traceback (most recent call last):
  File "/usr/lib/python3.6/threading.py", line 1294, in _shutdown
    t.join()
  File "/usr/lib/python3.6/threading.py", line 1056, in join
    self._wait_for_tstate_lock()
  File "/usr/lib/python3.6/threading.py", line 1072, in _wait_for_tstate_lock
    elif lock.acquire(block, timeout):
KeyboardInterrupt
$

这也发生在 Chrome 运行ning 正常情况下，UI，在 Docker 之外。

不管 Chrome 可能处理的是什么问题，似乎 "off" cproto 库应该像这样陷入困境。

有没有办法强制退出cproto？（是我上面哪里做错了，还是bug？）

Answer 1

看起来一些非守护线程在主线程退出后仍然存在运行。这个解决方法对我有用（还没有找到根本原因，需要更多调查）：

diff -ur cproto.orig/core/websocket.py cproto/core/websocket.py
--- cproto.orig/core/websocket.py       2021-01-04 01:24:53.000000000 +0000
+++ cproto/core/websocket.py    2021-03-10 04:10:32.228436532 +0000
@@ -38,8 +38,16 @@
     def connect(self, *args, **kwargs):
         super(self.__class__, self).connect(*args, **kwargs)
 
-        threading.Thread(target=self._read_messages).start()
-        threading.Thread(target=self._process_events).start()
+        # threading.Thread(target=self._read_messages).start()
+        # threading.Thread(target=self._process_events).start()
+
+        t1 = threading.Thread(target=self._read_messages)
+        t1.setDaemon(True)
+        t1.start()
+
+        t2 = threading.Thread(target=self._process_events)
+        t2.setDaemon(True)
+        t2.start()
 
     def close(self):
         # Terminates blocking `get` call on events processing thread

pypi cproto（chrome 调试客户端）在退出时挂起

pypi cproto (chrome debugging client) hangs on exit

python

python-3.x

google-chrome-devtools

chrome-debugging