Make cleanup more robust

Author: gnodar01

CP5/active_plugins/cpforeign/zmq_server.ipynb

@@ -35,6 +35,25 @@
     "DENIED = \"Denied\""
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def cleanup(context, socket):\n",
+    "    print(\"destroying existing context\")\n",
+    "    if socket:\n",
+    "        socket.close()\n",
+    "    if context:\n",
+    "        context.term()\n",
+    "        # destroy is more destructive\n",
+    "        # doesn't require sockets closed first\n",
+    "        # may leave them hanging if managed by other threads\n",
+    "        context.destroy()\n",
+    "    print(\"socket closed\", socket.closed, \"context closed\", context.closed)\n"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -43,11 +62,20 @@
    "source": [
     "context = zmq.Context()\n",
     "socket = context.socket(zmq.PAIR)\n",
-    "socket.copy_threshold = 0\n",
+    "#socket.copy_threshold = 0\n",
     "b = socket.bind(SOCKET_ADDR)\n",
     "b"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "cleanup(context, socket)"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -345,6 +373,15 @@
    "source": [
     "# socket.send_string(\"Cancel\")"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "cleanup(context, socket)"
+   ]
   }
  ],
  "metadata": {

CP5/active_plugins/runforeignnb.py

@@ -114,23 +114,29 @@ def run(self, workspace):
     def do_server_handshake(self):
         def cleanup():
             LOGGER.debug("destroying existing context")
-            if self.server_socket:
+            if self.server_socket is not None:
                 self.server_socket.close()
+                LOGGER.debug(f"socket closed: {self.server_socket.closed}")
                 self.server_socket = None
-            if self.context:
+            if self.context is not None:
                 self.context.term()
+                # destroy is more destructive
+                # doesn't require sockets closed first
+                # may leave them hanging if managed by other threads
                 self.context.destroy()
+                LOGGER.debug(f"context closed: {self.context.closed}")
+                self.context = None
 
         port = str(self.server_port.value)
         domain = "localhost"
         socket_addr = f"tcp://{domain}:{port}"
 
-        if self.context:
+        if self.context is not None or self.server_socket is not None:
             cleanup()
 
         self.context = zmq.Context()
         self.server_socket = self.context.socket(zmq.PAIR)
-        self.server_socket.copy_threshold = 0
+        #self.server_socket.copy_threshold = 0
 
         LOGGER.debug(f"connecting to {socket_addr}")