Add extra mqtt3 callbacks (#476)

* add extra mqtt3 callbacks `on_connection_success`, `on_connection_failure`, `on_connection_closed`

Author: sbSteveK

awsiot/mqtt_connection_builder.py

@@ -39,6 +39,27 @@
 
             *   `**kwargs` (dict): Forward-compatibility kwargs.
 
+    **on_connection_success** (`Callable`): Optional callback invoked whenever the connection successfully connects.
+        The function should take the following arguments and return nothing:
+
+            *   `connection` (:class:`awscrt.mqtt.Connection`): This MQTT Connection.
+
+            *   `callback_data` (:class:`awscrt.mqtt.OnConnectionSuccessData`): The data returned from the connection success.
+
+    **on_connection_failure** (`Callable`): Optional callback invoked whenever the connection fails to connect.
+        The function should take the following arguments and return nothing:
+
+            *   `connection` (:class:`awscrt.mqtt.Connection`): This MQTT Connection.
+
+            *   `callback_data` (:class:`awscrt.mqtt.OnConnectionFailureData`): The data returned from the connection failure.
+
+    **on_connection_closed** (`Callable`): Optional callback invoked whenever the connection has been disconnected and shutdown successfully.
+        The function should take the following arguments and return nothing:
+
+            *   `connection` (:class:`awscrt.mqtt.Connection`): This MQTT Connection.
+
+            *   `callback_data` (:class:`awscrt.mqtt.OnConnectionClosedData`): The data returned from the connection close.
+
     **clean_session** (`bool`): Whether or not to start a clean session with each reconnect.
         If True, the server will forget all subscriptions with each reconnect.
         Set False to request that the server resume an existing session
@@ -230,6 +251,9 @@ def _builder(
         use_websockets=use_websockets,
         websocket_handshake_transform=websocket_handshake_transform,
         proxy_options=proxy_options,
+        on_connection_success=_get(kwargs, 'on_connection_success'),
+        on_connection_failure=_get(kwargs, 'on_connection_failure'),
+        on_connection_closed=_get(kwargs, 'on_connection_closed'),
     )
 
 

samples/pubsub.py

@@ -58,6 +58,19 @@ def on_message_received(topic, payload, dup, qos, retain, **kwargs):
     if received_count == cmdData.input_count:
         received_all_event.set()
 
+# Callback when the connection successfully connects
+def on_connection_success(connection, callback_data):
+    assert isinstance(callback_data, mqtt.OnConnectionSuccessData)
+    print("Connection Successful with return code: {} session present: {}".format(callback_data.return_code, callback_data.session_present))
+
+# Callback when a connection attempt fails
+def on_connection_failure(connection, callback_data):
+    assert isinstance(callback_data, mqtt.OnConnectionFailuredata)
+    print("Connection failed with error code: {}".format(callback_data.error))
+
+# Callback when a connection has been disconnected or shutdown successfully
+def on_connection_closed(connection, callback_data):
+    print("Connection closed")
 
 if __name__ == '__main__':
     # Create the proxy options if the data is present in cmdData
@@ -79,7 +92,10 @@ def on_message_received(topic, payload, dup, qos, retain, **kwargs):
         client_id=cmdData.input_clientId,
         clean_session=False,
         keep_alive_secs=30,
-        http_proxy_options=proxy_options)
+        http_proxy_options=proxy_options,
+        on_connection_success=on_connection_success,
+        on_connection_failure=on_connection_failure,
+        on_connection_closed=on_connection_closed)
 
     if not cmdData.input_is_ci:
         print(f"Connecting to {cmdData.input_endpoint} with client ID '{cmdData.input_clientId}'...")