Support for concurrent connections with tunnels (#7719)

* Support for concurrent connections with tunnels

* Updated history and incremented patch version

* disabling the broad exception

The code is consistent with the rest of the file.

src/bastion/HISTORY.rst

@@ -2,6 +2,10 @@
 
 Release History
 ===============
+1.0.1
++++++
+* Added support for concurrent connections.
+
 1.0.0
 ++++++
 * Removing preview flag and update MFA documentation.

src/bastion/azext_bastion/tunnel.py

@@ -18,7 +18,7 @@
 import logging as logs
 from contextlib import closing
 from datetime import datetime
-from threading import Thread
+from threading import Thread, Lock
 import requests
 import urllib3
 
@@ -54,6 +54,8 @@ def __init__(self, cli_ctx, local_addr, local_port, bastion, bastion_endpoint, r
         self.node_id = None
         self.host_name = None
         self.cli_ctx = cli_ctx
+        self.active_connections = 0
+        self.connection_lock = Lock()
         logger.info('Creating a socket on port: %s', self.local_port)
         self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         logger.info('Setting socket options')
@@ -118,8 +120,16 @@ def _listen(self):
         self.sock.listen(100)
         index = 0
         while True:
-            self.client, _address = self.sock.accept()
-
+            client, _address = self.sock.accept()
+            with self.connection_lock:
+                self.active_connections += 1
+            logger.info('Got a connection, starting a new thread')
+            thread = Thread(target=self._handle_client, args=(client, index))
+            thread.start()
+            index += 1
+
+    def _handle_client(self, client, index):
+        try:
             auth_token = self._get_auth_token()
             if self.bastion['sku']['name'] == BastionSku.QuickConnect.name or \
                self.bastion['sku']['name'] == BastionSku.Developer.name:
@@ -128,22 +138,27 @@ def _listen(self):
                 host = f"wss://{self.bastion_endpoint}/webtunnelv2/{auth_token}?X-Node-Id={self.node_id}"
 
             verify_mode = ssl.CERT_NONE if should_disable_connection_verify() else ssl.CERT_REQUIRED
-            self.ws = create_connection(host,
-                                        sockopt=((socket.IPPROTO_TCP, socket.TCP_NODELAY, 1),),
-                                        sslopt={'cert_reqs': verify_mode},
-                                        enable_multithread=True)
-            logger.info('Websocket, connected status: %s', self.ws.connected)
-            index = index + 1
+            ws = create_connection(host,
+                                   sockopt=((socket.IPPROTO_TCP, socket.TCP_NODELAY, 1),),
+                                   sslopt={'cert_reqs': verify_mode},
+                                   enable_multithread=True)
+            logger.info('Websocket, connected status: %s', ws.connected)
             logger.info('Got debugger connection... index: %s', index)
-            debugger_thread = Thread(target=self._listen_to_client, args=(self.client, self.ws, index))
-            web_socket_thread = Thread(target=self._listen_to_web_socket, args=(self.client, self.ws, index))
+            debugger_thread = Thread(target=self._listen_to_client, args=(client, ws, index))
+            web_socket_thread = Thread(target=self._listen_to_web_socket, args=(client, ws, index))
             debugger_thread.start()
             web_socket_thread.start()
             logger.info('Both debugger and websocket threads started...')
             logger.info('Successfully connected to local server..')
             debugger_thread.join()
             web_socket_thread.join()
-            self.cleanup()
+        except Exception as ex:  # pylint: disable=broad-except
+            logger.info('Exception in handling client: %s', ex)
+        finally:
+            with self.connection_lock:
+                self.active_connections -= 1
+                if self.active_connections == 0:
+                    self.cleanup()
             logger.info('Both debugger and websocket threads stopped...')
             logger.info('Stopped local server..')
 

src/bastion/setup.py

@@ -10,7 +10,7 @@
 
 
 # HISTORY.rst entry.
-VERSION = '1.0.0'
+VERSION = '1.0.1'
 
 # The full list of classifiers is available at
 # https://pypi.python.org/pypi?%3Aaction=list_classifiers