allow to set socket timeout

fixes #112

Author: vladak

adafruit_minimqtt/adafruit_minimqtt.py

@@ -129,6 +129,7 @@ class MQTT:
     :param socket socket_pool: A pool of socket resources available for the given radio.
     :param ssl_context: SSL context for long-lived SSL connections.
     :param bool use_binary_mode: Messages are passed as bytearray instead of string to callbacks.
+    :param int socket_timeout: socket timeout, in seconds
 
     """
 
@@ -145,13 +146,15 @@ def __init__(
         socket_pool=None,
         ssl_context=None,
         use_binary_mode=False,
+        socket_timeout=1,
     ):
 
         self._socket_pool = socket_pool
         self._ssl_context = ssl_context
         self._sock = None
         self._backwards_compatible_sock = False
         self._use_binary_mode = use_binary_mode
+        self._socket_timeout = socket_timeout
 
         self.keep_alive = keep_alive
         self._user_data = None
@@ -209,12 +212,12 @@ def __init__(
         self.on_unsubscribe = None
 
     # pylint: disable=too-many-branches
-    def _get_connect_socket(self, host, port, *, timeout=1):
+    def _get_connect_socket(self, host, port, *, timeout):
         """Obtains a new socket and connects to a broker.
 
         :param str host: Desired broker hostname
         :param int port: Desired broker port
-        :param int timeout: Desired socket timeout
+        :param int timeout: Desired socket timeout in seconds
         """
         # For reconnections - check if we're using a socket already and close it
         if self._sock:
@@ -444,7 +447,9 @@ def connect(self, clean_session=True, host=None, port=None, keep_alive=None):
             self.logger.debug("Attempting to establish MQTT connection...")
 
         # Get a new socket
-        self._sock = self._get_connect_socket(self.broker, self.port)
+        self._sock = self._get_connect_socket(
+            self.broker, self.port, timeout=self._socket_timeout
+        )
 
         # Fixed Header
         fixed_header = bytearray([0x10])