asyncconnection: raise handle_error on connect exception

This happens for DNS errors.
Requires agents locks to be re-entrant as event_close will be called in start.

iotlabmqtt/asyncconnection.py

@@ -5,6 +5,10 @@
 Implement a class for AsyncoreService and a NodeConnection with handlers.
 """
 
+from __future__ import (absolute_import, division, print_function,
+                        unicode_literals)
+from builtins import *  # pylint:disable=W0401,W0614,W0622
+
 import socket
 import threading
 import asyncore
@@ -48,11 +52,12 @@ def handle_data(self, data):
 
     def start(self):
         """Connects to node serial port:"""
+
         self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
         try:
             self.connect(self.address)
-        except (IOError, OverflowError):
-            self.handle_close()
+        except:  # pylint:disable=broad-except,bare-except
+            self.handle_error()
 
     def handle_connect(self):
         """Node connected."""

iotlabmqtt/serial.py

@@ -354,7 +354,8 @@ def __init__(self, archi, num,  # pylint:disable=too-many-arguments
         self.connection = SerialConnection(archi, num, self.conn_event_handler,
                                            service=asyncoreservice)
 
-        self._lock = threading.Lock()
+        # Required Rlock, connection socket errors calls event_handler('close')
+        self._rlock = threading.RLock()
 
     @staticmethod
     def hostname(archi, num):
@@ -386,7 +387,7 @@ def _reply_request(self, reply, newstate=None):
         self.reply_publisher(reply.encode('utf-8'))
         self.reply_publisher = None
 
-    @common.synchronized('_lock')
+    @common.synchronized('_rlock')
     def close(self):
         """Close connection and state."""
         self._close()
@@ -401,7 +402,7 @@ def _close(self):
         self.closed_cb(self)
         return previous_state
 
-    @common.synchronized('_lock')
+    @common.synchronized('_rlock')
     def conn_event_handler(self, event):
         """Handler for connection events."""
         event_handler = {
@@ -433,7 +434,7 @@ def _event_close(self):
         # Jumps to event error
         raise Exception('Connection closed in state %s' % self.state)
 
-    @common.synchronized('_lock')
+    @common.synchronized('_rlock')
     def req_linestart(self, reply_publisher, line_handler):
         """Request to start line."""
 
@@ -453,7 +454,7 @@ def req_linestart(self, reply_publisher, line_handler):
         self.connection.start()
         return None
 
-    @common.synchronized('_lock')
+    @common.synchronized('_rlock')
     def lineinput(self, payload):
         """Send ``payload`` with a newline to the node connection."""
         if self.state != 'line':

iotlabmqtt/tests/integration_tests/serial_integration_test.py

@@ -151,6 +151,27 @@ def _test_serial_agent_no_port(self, client, stdout):
         stdout.seek(0)
         stdout.truncate(0)
 
+    def test_serial_agent_dns_fail(self):
+        """Test connecting on non existing dns node."""
+        with self.start_client_and_server(self.BROKERPORT) as (client, stdout):
+            self._test_serial_agent_dns_fail(client, stdout)
+
+    def _test_serial_agent_dns_fail(self, client, stdout):
+        """This dns error is raised directly by connect.
+
+        So it triggers a different path than an async failure.
+        """
+
+        # Start line non existing dns entry (even on IoT-LAB, raises DNS fail)
+        client.onecmd('linestart m3 1234')
+
+        # Error message
+        err = ('Connection failed: '
+               '[Errno -5] No address associated with hostname\n')
+        self.assertEqual(stdout.getvalue(), err)
+        stdout.seek(0)
+        stdout.truncate(0)
+
     def test_serial_agent_conn_stop(self):
         """Connection stops on one node, and stopall."""
         with self.start_client_and_server(self.BROKERPORT) as (client, stdout):