SangamAngre SangamAngre - 3 months ago 20
Python Question

How to troubleshoot mqtt and AWS iot

I am newbie to AWS IoT and MQTT as well. I am trying with simple example to read payload from AWS and publish payload to AWS. I am able to read payload on device but not able to publish. When I update shadow state from AWS console my raspberry pi able to receive the message but when I am publishing nothing happening. Not even state is changing on AWS console.

Code is attached. Please suggest.



def on_connect(mqttc, obj, flags, rc):
if rc==0:
print ("Subscriber Connection status code: "+str(rc)+" | Connection status: successful")
elif rc==1:
print ("Subscriber Connection status code: "+str(rc)+" | Connection status: Connection refused")

def on_subscribe(mqttc, obj, mid, granted_qos):
print("Subscribed: "+str(mid)+" "+str(granted_qos)+"data"+str(obj))
first_message()

def on_message(mqttc, obj, msg):
print("Received message from topic: "+msg.topic+" | QoS: "+str(msg.qos)+" | Data Received: "+str(msg.payload))

def on_publish(client, userdata, mid):
print("Message is published")

def first_message():
data = {} data['r'] = 2 data['g'] = 255 data['b'] = 95 data2 = {} data2['color'] = data data3 = {} data3['reported'] = data2 data4 = {}
data4['state'] = data3 json_data = json.dumps(data4) print(str(json_data))
(rc, mid) = mqttc.publish("$aws/things/thirdthing/shadow/update/", str(json_data), 1)

mqttc = mqtt.Client(client_id="thirdthing1")
mqttc.on_connect = on_connect
mqttc.on_subscribe = on_subscribe
mqttc.on_message = on_message
mqttc.on_publish = on_publish
mqttc.tls_set("/home/pi/deviceSDK/root-CA.crt",
certfile="/home/pi/deviceSDK/7391d7d21d-certificate.pem.crt",
keyfile="/home/pi/deviceSDK/7391d7d21d-private.pem.key",
tls_version=ssl.PROTOCOL_TLSv1_2,
ciphers=None)
mqttc.connect("AYYCW0HM971XS.iot.us-west-2.amazonaws.com", port=8883) #AWS IoT service hostname and portno
mqttc.subscribe("$aws/things/thirdthing/shadow/update/#", qos=1) #The names of these topics start with $aws/things/thingName/shadow."
mqttc.loop_forever()




Answer

Ok I solved this on myself.

Error in above code is json data formalization which I was sending. If I replace first_message() function with given code then this example works perfectly.

def first_message():
    payload = json.dumps({
        "state":{
            "reported":{
                "this_thing_is_alive":True,
                "color":{
                    "r":255,
                    "g":1,
                    "b":255
                }
            }
        }
    })

    mqttc.publish("$aws/things/thirdthing/shadow/update", payload)