Fix shutdown deprecation, #63

Author: T4rk1n

jupyter_dash/_stoppable_thread.py

@@ -0,0 +1,22 @@
+import ctypes
+import threading
+
+
+class StoppableThread(threading.Thread):
+    def get_id(self):
+        if hasattr(self, "_thread_id"):
+            return self._thread_id
+        for thread_id, thread in threading._active.items():
+            if thread is self:
+                return thread_id
+
+    def kill(self):
+        thread_id = self.get_id()
+        res = ctypes.pythonapi.PyThreadState_SetAsyncExc(
+            ctypes.c_long(thread_id), ctypes.py_object(SystemExit)
+        )
+        if res == 0:
+            raise ValueError(f"Invalid thread id: {thread_id}")
+        if res > 1:
+            ctypes.pythonapi.PyThreadState_SetAsyncExc(ctypes.c_long(thread_id), None)
+            raise SystemExit("Stopping thread failure")

jupyter_dash/jupyter_app.py

@@ -1,9 +1,7 @@
 import dash
 import os
 import requests
-from flask import request
 import flask.cli
-from threading import Thread
 from retrying import retry
 import io
 import re
@@ -19,6 +17,7 @@
 import uuid
 
 from .comms import _dash_comm, _jupyter_config, _request_jupyter_config
+from ._stoppable_thread import StoppableThread
 
 
 def _get_skip(error: Exception):
@@ -49,6 +48,8 @@ class JupyterDash(dash.Dash):
     _in_colab = "google.colab" in sys.modules
     _token = str(uuid.uuid4())
 
+    _server_threads = {}
+
     @classmethod
     def infer_jupyter_proxy_config(cls):
         """
@@ -138,15 +139,6 @@ def __init__(self, name=None, server_url=None, **kwargs):
 
         self.server_url = server_url
 
-        # Register route to shut down server
-        @self.server.route('/_shutdown_' + JupyterDash._token, methods=['GET'])
-        def shutdown():
-            func = request.environ.get('werkzeug.server.shutdown')
-            if func is None:
-                raise RuntimeError('Not running with the Werkzeug Server')
-            func()
-            return 'Server shutting down...'
-
         # Register route that we can use to poll to see when server is running
         @self.server.route('/_alive_' + JupyterDash._token, methods=['GET'])
         def alive():
@@ -225,7 +217,9 @@ def run_server(
             inline_exceptions = mode == "inline"
 
         # Terminate any existing server using this port
-        self._terminate_server_for_port(host, port)
+        old_server = self._server_threads.get((host, port))
+        if old_server:
+            old_server.kill()
 
         # Configure pathname prefix
         requests_pathname_prefix = self.config.get('requests_pathname_prefix', None)
@@ -297,12 +291,17 @@ def run_server(
             wait_exponential_max=1000
         )
         def run():
-            super_run_server(**kwargs)
+            try:
+                super_run_server(**kwargs)
+            except SystemExit:
+                pass
 
-        thread = Thread(target=run)
+        thread = StoppableThread(target=run)
         thread.setDaemon(True)
         thread.start()
 
+        self._server_threads[(host, port)] = thread
+
         # Wait for server to start up
         alive_url = "http://{host}:{port}/_alive_{token}".format(
             host=host, port=port, token=JupyterDash._token
@@ -414,16 +413,6 @@ def _wrap_errors(error):
 
             return html_str, 500
 
-    @classmethod
-    def _terminate_server_for_port(cls, host, port):
-        shutdown_url = "http://{host}:{port}/_shutdown_{token}".format(
-            host=host, port=port, token=JupyterDash._token
-        )
-        try:
-            response = requests.get(shutdown_url)
-        except Exception as e:
-            pass
-
 
 def _custom_formatargvalues(
         args, varargs, varkw, locals,