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The latest stable version is available in the Python Package Index (PyPi) and can be installed using

pip3 install gmqtt

Here is a very simple example that subscribes to the broker TOPIC topic and prints out the resulting messages:

importasyncioimportosimportsignalimporttimefromgmqttimportClientasMQTTClient# gmqtt also compatibility with uvloopimportuvloopasyncio.set_event_loop_policy(uvloop.EventLoopPolicy())STOP=asyncio.Event()defon_connect(client,flags,rc,properties):print('Connected')client.subscribe('TEST/#',qos=0)defon_message(client,topic,payload,qos,properties):print('RECV MSG:',payload)defon_disconnect(client,packet,exc=None):print('Disconnected')defon_subscribe(client,mid,qos,properties):print('SUBSCRIBED')defask_exit(*args):STOP.set()asyncdefmain(broker_host,token):client=MQTTClient("client-id")client.on_connect=on_connectclient.on_message=on_messageclient.on_disconnect=on_disconnectclient.on_subscribe=on_subscribeclient.set_auth_credentials(token,None)awaitclient.connect(broker_host)client.publish('TEST/TIME',str(time.time()),qos=1)awaitSTOP.wait()awaitclient.disconnect()if__name__=='__main__':loop=asyncio.get_event_loop()host='mqtt.flespi.io'token=os.environ.get('FLESPI_TOKEN')loop.add_signal_handler(signal.SIGINT,ask_exit)loop.add_signal_handler(signal.SIGTERM,ask_exit)loop.run_until_complete(main(host,token))

gmqtt supports MQTT version 5.0 protocol

Version 5.0 is used by default. If your broker does not support 5.0 protocol version and responds with proper CONNACK reason code, client will downgrade to 3.1 and reconnect automatically. Note, that some brokers just fail to parse the 5.0 format CONNECT packet, so first check manually if your broker handles this properly.You can also force version in connect method:

fromgmqtt.mqtt.constantsimportMQTTv311client=MQTTClient('clientid')client.set_auth_credentials(token,None)awaitclient.connect(broker_host,1883,keepalive=60,version=MQTTv311)

MQTT 5.0 protocol allows to include custom properties into packages, here is example of passing response topic property in published message:

TOPIC='testtopic/TOPIC'defon_connect(client,flags,rc,properties):client.subscribe(TOPIC,qos=1)print('Connected')defon_message(client,topic,payload,qos,properties):print('RECV MSG:',topic,payload.decode(),properties)asyncdefmain(broker_host,token):client=MQTTClient('asdfghjk')client.on_message=on_messageclient.on_connect=on_connectclient.set_auth_credentials(token,None)awaitclient.connect(broker_host,1883,keepalive=60)client.publish(TOPIC,'Message payload',response_topic='RESPONSE/TOPIC')awaitSTOP.wait()awaitclient.disconnect()

Connect properties are passed toClient object as kwargs (later they are stored together with properties received from broker inclient.properties field). See example below.

• session_expiry_interval -int Session expiry interval in seconds. If the Session Expiry Interval is absent the value 0 is used. If it is set to 0, or is absent, the Session ends when the Network Connection is closed. If the Session Expiry Interval is 0xFFFFFFFF (max possible value), the Session does not expire.
• receive_maximum -int The Client uses this value to limit the number of QoS 1 and QoS 2 publications that it is willing to process concurrently.
• user_property -tuple(str, str) This property may be used to provide additional diagnostic or other information (key-value pairs).
• maximum_packet_size -int The Client uses the Maximum Packet Size (in bytes) to inform the Server that it will not process packets exceeding this limit.

Example:

client=gmqtt.Client("lenkaklient",receive_maximum=24000,session_expiry_interval=60,user_property=('myid','12345'))

This properties will be also sent in publish packet from broker, they will be passed toon_message callback.

• message_expiry_interval -int If present, the value is the lifetime of the Application Message in seconds.
• content_type -unicode UTF-8 Encoded String describing the content of the Application Message. The value of the Content Type is defined by the sending and receiving application.
• user_property -tuple(str, str)
• subscription_identifier -int (see subscribe properties) sent by broker
• topic_alias -int First client publishes messages with topic string and kwarg topic_alias. After this initial message client can publish message with empty string topic and same topic_alias kwarg.

Example:

defon_message(client,topic,payload,qos,properties):# properties example here: {'content_type': ['json'], 'user_property': [('timestamp', '1524235334.881058')], 'message_expiry_interval': [60], 'subscription_identifier': [42, 64]}print('RECV MSG:',topic,payload,properties)client.publish('TEST/TIME',str(time.time()),qos=1,retain=True,message_expiry_interval=60,content_type='json')

• subscription_identifier -int If the Client specified a Subscription Identifier for any of the overlapping subscriptions the Server MUST send those Subscription Identifiers in the message which is published as the result of the subscriptions.

By default, connected MQTT client will always try to reconnect in case of lost connections. Number of reconnect attempts is unlimited.If you want to change this behaviour, do the following:

client=MQTTClient("client-id")client.set_config({'reconnect_retries':10,'reconnect_delay':60})

Code above will set number of reconnect attempts to 10 and delay between reconnect attempts to 1min (60s). By defaultreconnect_delay=6 andreconnect_retries=-1 which stands for infinity.Note that manually callingawait client.disconnect() will setreconnect_retries for 0, which will stop auto reconnect.

You can define asynchronous on_message callback.Note that it must return valid PUBACK code (0 is success code, see full list inconstants)

asyncdefon_message(client,topic,payload,qos,properties):passreturn0

Checkexamples directory for more use cases.