MQTT: make usage of connect_async optional

environment.yml

@@ -0,0 +1,79 @@
+name: Flask-MQTT
+channels:
+  - conda-forge
+  - pytorch
+  - defaults
+dependencies:
+  - attrs=19.3.0=py_0
+  - bleach=3.1.0=py_0
+  - ca-certificates=2019.11.28=hecc5488_0
+  - certifi=2019.11.28=py37_0
+  - cffi=1.13.2=py37h33e799b_0
+  - chardet=3.0.4=py_1004
+  - click=7.0=py_0
+  - cmarkgfm=0.4.2=py37h0b31af3_2
+  - cryptography=2.8=py37hafa8578_1
+  - dnspython=1.16.0=py_1
+  - docutils=0.16=py37_0
+  - ecdsa=0.13=py_0
+  - entrypoints=0.3=py37_1000
+  - eventlet=0.25.1=py37_0
+  - filelock=3.0.10=py_0
+  - flask=1.1.1=py_1
+  - flask-socketio=3.3.2=py_0
+  - future=0.18.2=py37_0
+  - gmp=6.2.0=h4a8c4bd_1
+  - greenlet=0.4.15=py37h0b31af3_0
+  - idna=2.8=py37_1000
+  - importlib_metadata=0.23=py37_0
+  - inflect=4.1.0=py37_0
+  - itsdangerous=1.1.0=py_0
+  - jaraco.itertools=5.0.0=py_0
+  - jinja2=2.11.1=py_0
+  - keyring=21.1.0=py37_0
+  - libcxx=9.0.1=1
+  - libffi=3.2.1=h6de7cb9_1006
+  - markupsafe=1.1.1=py37h0b31af3_0
+  - monotonic=1.5=py_0
+  - more-itertools=8.2.0=py_0
+  - ncurses=6.1=h0a44026_1002
+  - openssl=1.1.1d=h0b31af3_0
+  - packaging=20.1=py_0
+  - paho-mqtt=1.5.0=py_0
+  - pip=20.0.2=py_2
+  - pkginfo=1.5.0.1=py_0
+  - pluggy=0.12.0=py_0
+  - py=1.8.1=py_0
+  - pycparser=2.19=py37_1
+  - pycryptodome=3.9.6=py37h65ac59c_0
+  - pygments=2.5.2=py_0
+  - pyopenssl=19.1.0=py37_0
+  - pyparsing=2.4.6=py_0
+  - pysocks=1.7.1=py37_0
+  - pytest=5.3.5=py37_0
+  - python=3.7.6=h5c2c468_2
+  - python-engineio=3.0.0=py_0
+  - python-socketio=3.1.2=py_0
+  - readline=8.0=hcfe32e1_0
+  - readme_renderer=24.0=py_0
+  - requests=2.22.0=py37_1
+  - requests-toolbelt=0.9.1=py_0
+  - setuptools=45.1.0=py37_0
+  - six=1.14.0=py37_0
+  - sqlite=3.30.1=h93121df_0
+  - tk=8.6.10=hbbe82c9_0
+  - toml=0.10.0=py_0
+  - tox=3.14.3=py_0
+  - tqdm=4.42.1=py_0
+  - twine=3.1.1=py37_0
+  - urllib3=1.25.7=py37_0
+  - virtualenv=16.7.5=py_0
+  - wcwidth=0.1.8=py_0
+  - webencodings=0.5.1=py_1
+  - werkzeug=1.0.0=py_0
+  - wheel=0.34.2=py_1
+  - xz=5.2.4=h1de35cc_1001
+  - zipp=2.1.0=py_0
+  - zlib=1.2.11=h0b31af3_1006
+prefix: /Users/stefan/.pyenv/versions/anaconda3-2019.07/envs/Flask-MQTT
+

flask_mqtt/__init__.py

@@ -63,9 +63,10 @@
 class Mqtt():
     """Main Mqtt class."""
 
-    def __init__(self, app=None, mqtt_logging=False):
-        # type: (Flask) -> None
+    def __init__(self, app=None, connect_async=False, mqtt_logging=False):
+        # type: (Flask, bool, bool) -> None
         self.app = app
+        self._connect_async = connect_async  # type: bool
         self._connect_handler = None  # type: Optional[Callable]
         self._disconnect_handler = None  # type: Optional[Callable]
         self.topics = {}  # type: Dict[str, TopicQos]
@@ -147,20 +148,25 @@ def _connect(self):
             if self.tls_insecure:
                 self.client.tls_insecure_set(self.tls_insecure)
 
-        res = self.client.connect_async(
-            self.broker_url, self.broker_port, keepalive=self.keepalive
-        )
-
-        if res == 0:
-            logger.debug(
-                "Connected client '{0}' to broker {1}:{2}"
-                .format(self.client_id, self.broker_url, self.broker_port)
+        if self._connect_async:
+            # if connect_async is used
+            self.client.connect_async(
+                self.broker_url, self.broker_port, keepalive=self.keepalive
             )
         else:
-            logger.error(
-                "Could not connect to MQTT Broker, Error Code: {0}".format(res)
+            res = self.client.connect(
+                self.broker_url, self.broker_port, keepalive=self.keepalive
             )
 
+            if res == 0:
+                logger.debug(
+                    "Connected client '{0}' to broker {1}:{2}"
+                    .format(self.client_id, self.broker_url, self.broker_port)
+                )
+            else:
+                logger.error(
+                    "Could not connect to MQTT Broker, Error Code: {0}".format(res)
+                )
         self.client.loop_start()
 
     def _disconnect(self):